Category: Concrete Maintenance

As summer approaches us here at Kryton in Canada, we know that many of you will be planning your hot weather concreting. While the weather can be a joy to experience for yourself, it can also make concreting more challenging.

For one, high temperatures will accelerate the early-age strength gain of your concrete. This sounds like a great way to naturally expedite your schedule. But it’s hard to take advantage of that when you aren’t sure of how fast your concrete is developing.

Moreover, once high temperatures get excessively high, your concrete can develop a number of durability concerns. For instance, it can end up with delayed ettringite formation (DEF). And DEF can be quite a destructive force in moist environments as it can cause your concrete to prematurely deteriorate.

Outside of DEF, your concrete can also experience drying shrinkage. This happens when the concrete has suffered moisture loss after hardening. It increases the concrete’s tensile stress, raising the likelihood that the concrete will crack or warp.

All of which is terrible for constructing a solid, reliable structure. However, you can reduce the risk of this happening during hot weather concreting with our Maturix Smart Concrete Sensors.

So, How Do Maturix Sensors Help?

They give you an easy way to stay on top of your concrete’s thermal control plan. Once connected to type K thermocouple wires, which are positioned and attached to reinforcing rebar, the Maturix Sensors wirelessly transmit temperature data to a cloud-based platform every 10 minutes. Then, the platform takes that data and calculates the maturity based on the readings and a specific concrete calibration curve. In return, you get a result that accurately determines your concrete’s current strength. All of which allows you to tell exactly what temperature and strength your concrete has every day. And because this information is transmitted wirelessly, you can access it through any connected device, keeping you up-to-date on the situation, no matter where you are. Additionally, you can easily set up alarms to receive notifications via SMS or email when a certain temperature, strength, or maturity has been reached.

That in turn allows you to stick to the recommended temperatures for hot weather concreting and operate proactively as specified in ACI 305R: Guide to Hot Weather Concreting.

Of course, that’s just the start. There are a couple other advantages that come with Maturix. Let’s take a look at them.

They Enable You to Leverage Early Concrete Strength in Hot Temperatures

To start, with the insight they provide on strength development, you’ll notice right away when your concrete starts reacting to hotter temperatures. After all, you’ll see exactly when the concrete’s strength accelerates. So you’ll be able to plan your schedule to work with this expedited strength development. In turn, you’ll find yourself stripping forms at a faster rate, letting you keep up with any tight deadlines you have.

nd Their Real-Time Alert System Makes It Easy to Avoid Potential Temperature Concerns

You can set up this alert system to notify you and your team when the concrete meets, exceeds, or goes below critical thresholds. So long as you have a connected device, you’ll immediately know when your concrete is doing well and when it needs adjustments. That way, if your concrete ever exceeds recommended temperatures, you and your team can take the required actions to cool it down.

In short, Maturix empowers you to fix temperature concerns before they ever become a problem.

Why Choose Them Over Other Available Sensors for Hot Weather Concreting?

Still, there are other sensors out there. What makes Maturix worthy of more consideration?

Well, Maturix comes with a number of unique features you aren’t likely to find elsewhere. Some of which include the following.

You Get Local Weather Data as Well as Temperature and Strength Data

To further bolster your understanding of your concrete’s development, Maturix Sensors gather data about the local weather. That way, you don’t just know how your concrete is doing. You also get a sense for what conditions your concrete faces throughout your construction project. Whether you have to deal with hot weather and rain or any other weather combination, you get the weather data integrated in your reporting.

You’ll Even Be Able to Reuse Maturix Sensors for Multiple Projects

One of the best cost-effective measures of these devices is that they don’t work like single-use sensors. These aren’t disposable devices that remain within the concrete. Instead, they are connected to disposable thermocouple wires. As a result, once you complete a project, you are free to take the sensors with you and use them for other projects for as many times as you like. This allows you to take advantage of all the features Maturix offers at a low cost. After all, you don’t need to spend a big chunk of your budget on new sensors with Maturix.

In the end, Maturix is a worthwhile investment that cuts down on your costs and makes hot weather concreting much less risky.

So Why Not Give Them a Try for Your Next Hot Weather Concreting Project?

If you’re expecting to deal with such a project soon, then it might be time for you to find out how advantageous it can be to have Maturix with you. You’ll soon wonder how you could have gone so long without it! But don’t just take our word for it. Check out our Maturix page to see for yourself.

The post Reducing the Risk of Hot Weather Concreting with Maturix® Sensors appeared first on Kryton.

Providing the best results for clients: that’s what most contractors strive for. And Kruse Smith is no different. That’s why the Norwegian contractor has recently started digitalizing their work for the E39 highway project. As part of this process, they took a special focus on technological innovations and how those could improve their on-site performance. That has allowed them to minimize any repetition, time consumption, and labor costs associated with their work while producing more cost-effective and timely end results.

More specifically, it has allowed them to effectively develop the 19 km (11.8 mi) of the E39 project that they are responsible for.

However, the project as a whole is likely to be the largest coastal highway infrastructure Norway has ever conducted. At about 1,100 km (683.51 mi), the project is expected to replace multiple ferry travel points and cut down travel time from 21 hours to just 13.

To optimize their part in this extensive project, Kruse Smith conducted a digital pilot project, enacting innovative changes, such as replacing paper plans with 3D modeling and BIM and using wireless sensors for concrete monitoring.

These wireless sensors (also known as Maturix Smart Concrete Sensors) help optimize Kruse Smith’s work on-site by enabling the contractor to remotely monitor the temperature and strength development of multiple concrete structures in real time. It’s a method that saves them time and money that they would have otherwise spent on physically checking each concrete form.

For more details on how this innovative technology is helping the contractor move forward on the E39 project, the creator of Maturix, Sensohive Technologies ApS, conducted an interview with two members of Kruse Smith’s team, Marius Røksland, and Asbjørn Stålesen.

The interview gave great insight into the use of Maturix in the infrastructure project. And we are happy to add to the conversation, sharing additional interview details on how Maturix helped Kruse Smith in their everyday work.

To talk about Kruse Smith’s work on the E39 project and their use of Maturix, we have two members from their team. Can you tell us a little bit about yourselves?

Marius: My name is Marius Røksland, and I work for Kruse Smith as a project engineer.

Asbjørn: I am Asbjørn Stålesen, and I’m the project manager for the new E39 between Kristiansand and Mandal.

What are you currently working on?

Marius: At the moment, at this jobsite, we are building 19 bridges, completing the new E39 highway. It’s a four-speed, 110-kilometer [68-mile] highway on the coast of Norway, all the way south. It is one of many small stretches of roads that we have been constructing.

For this one, now, we have been working for a couple of years and still have one-and-a-half years to go.

This bridge is about 370 meters long. It’s a dual lane, so we are doing two at the same time.

How far are you with the bridge?

Asbjørn: Currently, we are 90-, 95-percent finished. We have cast all three bridges, but we have some of the small works around them left before we can hand them over to the client.

On this particular project, we have all cast-in-place. We have no precast, and we do this with quite big formworks.

These are 120-meter [393.71-foot] bridges, but we reuse the formworks from one to the other. So we try to do as much of that as we can, but it’s important for us to think industrial scale because we’ve been building so many bridges in such a short time. This is also why monitoring the curing process enables us to move on a lot faster as we know exactly when we can remove the formwork.

What are the challenges of this project?

Marius: The weather is a challenge as it is way too cold. We have problems with ice and snow here in Norway, especially now when it’s so cold. So it’s important for us to know the concrete temperature in the whole bridge and every cast. This has mostly to do with the maximum temperature, but also now in these conditions, we really have to be careful not to have anything freeze until we get the curing.

There are also different aspects, but mostly, that the temperature may not differ too much from the core to the outer edges as the structure can get damaged otherwise. In the current temperatures with the cold, it is a challenge. So we really need to monitor the temperature!

Did you always monitor the concrete temperature in mass concreting?

Asbjørn: It’s always been a requirement that we monitor, but the other systems we used were offline. That means that you go and collect the data and you come back and analyze it.

This also means that in real life, you do this more than one time — maybe once if you’re lucky — and directly get the required result.

Marius: Before Maturix, we used manual data loggers. They were digital, but not wireless. Then, you had to take the sensors, set them up, leave the sensors, cross your fingers, and hope for the best. And then, some days later or some hours later, you have to go back out to the form, check whatever reading there is, collect it, put it into the computer, and see what you actually get.

Asbjørn: So even with the data loggers, it is still very time-consuming to set them up and go get them. Also, you really don’t know what the data looks like until you actually finish the casts and do the analysis. (With Maturix, you get all the graphics and analysis on the screen — live.) And you don’t get any chance of doing something as you progress through the curing process.

That means that you’re not really actively using the data. You’re crossing your fingers and hoping that everything has gone well, and afterwards, you have documentation that it did. It’s a very passive way of working compared to having the data available at all times.

How do you actively use the data?

Asbjørn: So that’s one aspect of it — better active documentation and quality control. Another is, if we forgot something and suddenly there is a change like a temperature drop or some kind of temperature change or another concrete mixture — or if it gets too hot, for instance — or you were expecting to see this curing process start in, say, eight hours, but you didn’t get it until it was 14 hours? Then, we can investigate further why and potentially save time next time by adjusting the mixture or doing some additional work prior to casting.

So, are you using the monitoring data to optimize future casts? Has that influenced internal teamwork?

Asbjørn: Yes. We see that in everyday life, we’re using the data so much more, and discussions around it have been brought up. The temperature data becomes an everyday topic instead of being something that a quality engineer does and documents. And we see that the data has been actively used to improve how we build.

How important is the monitoring data for you, and how do you use it?

Asbjørn: It’s important for us at all levels. For me, as a project manager, it’s important to keep control of all the work going on. We have work in a lot of different sites, and this enables me to keep track of ongoing castings and how they are doing. So basically, we can monitor the situation in real time so that we know what’s going on.

But it’s also important for us in everyday work, where we have control over all the curing processes at a much better level now. And we can much more accurately predict when the concrete is cured and when we can go to the next step.

But it’s also good from a quality aspect. We can use it in meetings and discuss how the castings are going and which areas of concern there might be or how we can adjust for future casts.

Marius: We can check whatever the concrete is doing and share the information with the client. That creates a lot of transparency and trust.

Who has access to the monitoring data?

Asbjørn: Well, we have chosen to share the access to the software with both our clients and third-party members. So everybody has full access to all the data, and the feedback from that is very good! They check the data, and they discuss it with us. We have a very good dialogue with all parties, and we get to share the knowledge of how to improve our quality of work.

It gives a whole new level of trust, showing them that we have nothing to hide. And this is very good to have in a project like this!

So, how easy do you think it would be for someone who has not used Maturix before to get started?

Asbjørn: We’re finding now that it doesn’t take much training at all and that people are really on board. People are really interested and want to use it as much as possible here, and it’s certainly not a system we will go away from.  It has come to stay with us.

Marius: You just take the cable, connect it to the transmitter, start it in the software, and you are ready to go. It’s super easy to get started.

What would you tell someone who is considering Maturix?

Marius: I think it would be better to show them. You get everything that you need, plus a lot more! You get all the data and don’t need to be on-site or do the analysis, so it just is better and quick and easy.

Asbjørn: I’m firmly recommending using the system. It gives you much more insight into what you’re doing. Also, together with your client, it gives you better client relations and a higher quality of work. So in my mind, this is the way forward!

Thank you so much for taking the time to talk with us, and good luck with your work on the E39 project!

The post Interview: Why Maturix® Is Contractor Kruse Smith’s Chosen Concrete Sensor appeared first on Kryton.

When you think of concrete, it’s likely not long before you’re thinking about its durability. It’s one of the more well-known advantages of the material. And it’s why many choose to use concrete in construction. After all, no one wants to build with a material that couldn’t withstand the outside elements. So we turn to that concrete durability, relying on it enough to make concrete one of the most consumed materials on the planet, second only to water.

But concrete isn’t invulnerable. Depending on its mix, you could have a maintenance liability on your hands. Luckily, there is a way to avoid that. All it takes is being aware of how you can convert your concrete slab from a maintenance liability to an asset.

Keep in Mind That Slabs Can Be Prone to Wear and Tear

The first step in the right direction is to remind yourself that while durable, concrete slabs can still be prone to wear and tear.

It’s why you look for concrete hardening products. They’re meant to add an extra layer of protection to the concrete’s surface, sheltering it from abrasive and erosive forces that might otherwise degrade the concrete.

You can probably think of quite a few culprits responsible for this wear and tear. But as a refresher, let’s look into the specific types of abrasion and erosion you’re likely protecting your concrete from.

Number of Abrasive Forces Can Cause This

As noted in our latest e-book (which you can download and check out for yourself here), there are three specific types of abrasion-only wear:

Sliding abrasion — Also known as two-body abrasion, it’s what happens when a hard object slides across concrete. As it moves, the hard object will begin to gradually bore into the concrete, removing a bit of its surface each time. So if you have skids or some other item with a hard material moving back and forth over your concrete frequently, you’ll start to notice a rut in its surface.

 

Foreign particle abrasion — For any concrete projects that deal with vehicles, you’re sure to come across foreign particle abrasion. That’s because as the vehicles travel over the concrete, hard particles get trapped between the vehicle tires and concrete surface, and that wears down both materials simultaneously.

 

Rolling abrasion — A common sight in industrial spaces, rolling abrasion is what happens when wheels under a heavy load roll over a concrete surface. These wheels might come from carts, forklifts, or other wheeled equipment. But whichever one it is, over time, their movement over the concrete surface wears that surface out and creates noticeable dips in the concrete.

Erosive Forces Can Also Cause Similar Damage

One of the more common types of erosive wear is actually a combination of abrasion and erosion. And it’s often seen in hydraulic projects.

Why?

Well, these projects are typically ones that are surrounded by fast-moving water, such as dams and spillways. So they are more likely to encounter the abrasive effect of debris in the water grinding against their concrete surfaces. This debris might come in the form of silt, sand, gravel, rocks, or even ice. And while it’s roughing up the surface of the concrete, the surrounding water rushing by is gradually causing the concrete to erode.

That Can Open the Door to Various Costly Risks

If either abrasion or erosion starts to seriously affect your concrete to the point that you can see the damage, it can create a safety hazard, disrupt operations, and increase maintenance costs.

For Floor Slabs, That Can Involve an Increased Danger of Slipping, Tripping, and Falling

All those dips and ruts in concrete flooring caused by abrasive wear? They can pose a threat to your team’s personal safety.

While for a time, you might be able to work around the uneven flooring, you or someone else on your team is inevitably going to slip, trip, or fall. In fact, it’d be close to a statistical anomaly if you didn’t! Slips, trips, and falls make up a third of lost-workday injuries according to the Centers for Disease Control and Prevention. And as EHS Today notes, the primary cause for more than half of these injuries is due to an issue with a walking surface. So you can imagine the risk you take with keeping that uneven floor!

The cost of not implementing preventative measures for this kind of risk for businesses in the United States of America (USA) alone is about $70 billion a year overall in compensation and medical fees for workers.

For Road Slabs, That Means Traffic Accidents

Similar to how uneven flooring can pose a risk to people walking over it, uneven roads can be a risk to those driving.

Initially, that unevenness might be a slight difference in road surface from all that foreign particle abrasion. But eventually, that slight dip might lead to potholes or a fully uneven road. It also increases tire wear, making the vehicles on the road less efficient and safe to use.

All of which increases the risk for roadway accidents. Potholes on their own cause around $3 billion in vehicular repairs annually in the USA. And in Canada, each year, the cost for drivers as a whole is increasing by that same amount because of increased vehicular repairs and maintenance and general vehicular damage due to poorly maintained roads.

Hazards like potholes pose an even greater risk for those on motorcycles and bikes.

Those on motorcycles, according to the Motorcycle Safety Foundation, may crash when encountering potholes. That can be a significant concern as motorcycle incidents have a 29% higher fatality risk than ones that occur with automobiles and light trucks.

For cyclists, they can end up with permanent nerve damage. But that’s not the worst-case scenario. Much like those on motorcycles, cyclists have a higher fatality rate when it comes to crashing. For instance, since 2007, in Britain, potholes alone have killed at least 22 cyclists and seriously injured another 368.

The Potential Damage Doesn’t Stop There Either

Of course, worker injuries and vehicular damage aren’t the only costs to consider when facing abrasion and erosion damage. You also have productivity, equipment, and structural loss to worry about.

For instance, workers operating forklifts on an uneven surface are likely to drive more slowly to avoid tipping over, reducing worksite productivity. And if they don’t? You’ll likely be paying to repair or replace that forklift and any items it happened to be carrying.

Using fully automated equipment won’t do much to overcome this obstacle on its own either as an uneven surface can prevent it from operating properly.

And what about structures? With enough abrasion and erosion, owners will have to close down for repairs and replace large sections of concrete structures, from floors all the way to hydro dams. All of which is extremely costly to any business and doesn’t endear owners to the concrete they used.

But Your Concrete Slab Doesn’t Have to Be a Maintenance Liability

You just need an effective concrete hardening solution.

Your first thought might be to use conventional surface-applied concrete hardeners like dry shake hardeners or liquid hardeners. However, those come with a number of setbacks.

Dry shake hardeners, for one, come with a complex application process. It’s not a one-and-done deal. Instead, a worksite team has to prepare the worksite first. That means removing excess concrete and preparing the remaining concrete. Then, depending on your chosen hardener’s material, you may have to take an extra step and use a wood bull float and then a machine float. After that, the team can finally move on to actually applying the dry shake hardener, which will cover a couple millimeters of the concrete’s surface.

However, even that part isn’t without complications. Dry shake hardeners can only be applied during a specific time and type of weather. Pick the wrong time and you can end up with delaminated concrete or an inability to even apply the dry shake.

At the same time, this hardener makes use of a toxic material known as silica dust, which means a worksite team needs to meet the proper safety measures to keep workers safe and comply with legal restrictions.

On the other hand, while not as frustrating to apply or as hazardous as dry shake hardeners, liquid hardeners are often misrepresented. They were first sold as dust reducers to help with defective concrete slabs that had a dusty surface. But now, they’re expected to harden concrete, which they do very poorly.

(For more reasons and data on why these aren’t effective solutions and more, take a look at our e-book on the topic!)

So, what can you use instead?

pply Hard-Cem to Increase Your Concrete Slab’s Resistance to Wear and Tear

Unlike any other concrete hardener on the market, Hard-Cem is an integral hardener. That means it applies its hardening properties throughout a concrete mix to form one solid abrasion- and erosion-resistant material. Essentially, it’s an admixture that you add into the concrete mix during batching. At that time, the admixture will permeate the entirety of the mix, giving it a harder concrete paste and reducing fine and coarse aggregate exposure. It does all this to help the concrete effectively resist abrasion and erosion.

Your Concrete Slab Will Gain Many Other Benefits as Well

More specifically, when using Hard-Cem, you’ll double the wear life of your concrete.  Because it does last that long and can resist abrasion and erosion, Hard-Cem-treated concrete comes with fewer maintenance fees. So you won’t need to resurface or replace your concrete as often. And you won’t need to use as much cement. That can increase your savings on carbon emissions by as much as 40%!

In some cases, this has even helped construction teams earn LEED certifications.

All you need to do to get these advantages is to throw the admixture and its dissoluble bag into the concrete mix during batching. There are no extra application steps, toxic silica dust, or inefficiencies to worry about. So you don’t have to spend money or time on hiring extra labor or managing application errors. Hard-Cem does all the heavy lifting, giving your mix the thorough durability it needs as soon as it’s added.

Hard-Cem also offers incredible versatility. It can work for a variety of projects and help harden horizontal, vertical, and inclined concrete. And it is the only hardener capable of being used for air-entrained concrete.

In short, it increases your concrete’s durability, speeds up your construction, reduces application costs, provides universal compatibility for different concrete mixes, and makes it all more sustainable.

It Just Takes the Right Concrete Mix Ingredients

With Hard-Cem added into your concrete mix, your concrete slabs will be an asset to your project. They’ll need less maintenance over the years, help you reduce your carbon emissions, and most importantly, keep abrasion and erosion at bay to keep your concrete structures standing for as long as possible.

The post Convert Your Concrete Slab from a Maintenance Liability to an Asset appeared first on Kryton.

Did you miss our previous article…
https://cedarparkconcrete.org/?p=246

After last year, we can all use a little extra fun this summer.

Not ready to go out yet? No worries!

By adding a patio to your backyard or enhancing your current one, you can bring the party straight to your house.

A stamped concrete patio is one of the best investments you can make this summer for a few reasons:

1. The material is unmatched

Compared to other popular choices like wood or pavers, stamped concrete is substantially more durable, easier to install, and requires a lot less maintenance. Not to mention, it can mimic the appearance of any other material at the most budget-friendly price on the market. 

2. It can be made to match any style

The stamped concrete process is pretty self-explanatory. It gets its appearance through specially-designed rubber roller stamps that are pressed into the wet material. Whether you want your slab to look like tile, wood, brick, or precious stone, it’s all possible. 

The options are truly endless with this type of concrete. Using stains, dyes, colored epoxy finishes, engravings, and overlays, your patio can be made to match any color scheme and incorporate any special logos, designs, patterns, or other features. 

3.  It opens up the door to so many possibilities

A stamped concrete patio can transform your yard into the ultimate summer fun space. Have you always wanted an outdoor kitchen? Are your kids fantasizing about roasting marshmallows over an open fire this summer?

All of this is possible when you have a beautiful outdoor space to gather. No matter what your style or taste is, you can make your dreams come true with a stamped concrete patio. 

Don’t let COVID steal another summer. Turn your home into the ultimate staycation resort with decorative concrete! At Port Aggregates, we’re here to help you create the perfect concrete patio to match your unique taste.

With more than 40 years in business and 24 locations across Louisiana, our contractors are well-versed in decorative concrete installation and design. Contact Port Aggregates today to request a quote

The post 3 Benefits of a Stamped Concrete Patio appeared first on Port Aggregates.

When it comes to taking care of stamped concrete, summer is the best season to do so.

With temperatures rising in Louisiana, now is the time to start preparing your concrete for the warmer weather to come.

To increase the longevity of your decorative concrete, you must follow the following 4 steps when preparing your slab for summer.

1. Make sure you don’t need to strip your concrete

After a particularly harsh winter (like the record-breaking freeze of 2020), you may want to consider resealing your concrete. 

Before you do so, however, you may wonder whether or not it’s necessary to strip off the old sealer first.

Fortunately, as long as your slab has been around longer than the early 2000s and has been stripped once before, it will not need stripping prior to resealing.

2. Power wash your slab

Once you’ve concluded whether or not you need to strip your stamped concrete, you’ll want to power wash it before you proceed with anything else.

Pollen, leaf, and tire stains can create such an eyesore. Power washing your slab is ideal for clearing away all the dirt, grime, and stains that have built up over the past year.

If you’ve got tough stains from oil and tar, you should use neutral soap, a solvent cleaner, or a degreaser first. This will loosen the stain which can then be sprayed off with the power washer.

3. Check for cracks

After your stamped concrete has been fully cleaned, scan it with your eyes for cracks. Most hairline fractures can be fixed on your own, but long and deep cracks may require you to replace the slab altogether.

4. Seal your concrete

If you haven’t resealed your concrete in the past three years, now is the best time to do so. Sealer is most effectively applied during warm weather on dry concrete. If you’re planning on sealing your concrete this spring, be sure to check the weather ahead of time, as the sealer will need a couple of days with no rain in order to dry properly.

Looking for more concrete tips and tricks? Check out the Port Aggregates blog

The post 4 Steps to Prepare Your Stamped Concrete for Summer appeared first on Port Aggregates.

While concrete is extremely strong, it can also be very brittle if it’s not properly mixed and cured. Concrete failure can occur in a variety of ways because of the versatility of this material and all of its applications.

Each type of failure is different and has its own causes and solutions. It’s important to understand how these common types of failures occur so that your project is not negatively affected.

Keep reading to learn 5 tips for preventing concrete failure.

1. Avoid trapped air 

Trapped air bubbles in concrete can cause it to fail. Concrete is a mixture of gravel, sand, and cement (among other ingredients), and when this mix gets poured into forms or molds, trapped air bubbles can form. 

These bubbles result in weak spots that aren’t able to handle pressure.

To avoid trapped air when mixing concrete, ideally, you should hire a professional with a mixer truck rather than attempting to mix and pour on your own. 

When mixing on your own, you risk adding too much water to the mix or mixing it for too long. This can cause small cracks and fissures which will leave your concrete vulnerable as well. 

2. Don’t overload concrete forms

Overloading concrete is another common cause of concrete failure. While concrete is one of the strongest materials on the planet, different types have different limits. For example, reinforced concrete should be used if you anticipate supporting a large weight or structure.

Unfortunately, some cheap contractors like to cut corners here by using the wrong type of concrete to complete the job faster. Then, once heavy loads are placed on the concrete, it cracks.

3. Always use good quality raw materials

Using good quality raw materials is another way to avoid concrete failure. This goes for both the sand and gravel used in your mix as well as the cement itself.

If you’re not using a reputable supplier, there’s no telling what sorts of additives they may be including in their products (or if any at all). 

For example, recycled or fly ash cement can sometimes be used in place of traditional Portland cement. While this is cheaper, it also has a shorter lifespan and may not meet the standards you’re looking for.

The same goes for sand or gravel that doesn’t measure up to your specifications. If it’s too coarse, the concrete mix won’t have enough cohesion between particles which can cause the material to crumble.

If you want strong, durable, and long-lasting concrete, always make sure to use a reputable contractor and supplier for raw materials.

4. Use water treated with low levels of dissolved sulphate

Using water with low levels of dissolved sulphate is another way to avoid concrete failure. You see, metal ions (especially iron or steel) can lead to the formation of rust within your concrete mix which will make it vulnerable and prone to cracking.

The easiest thing you can do here is use deionized water in place of tap water. If this isn’t available, try to use water with low levels of dissolved sulphate. This will prevent the metal ions from being deposited into your concrete mix which will result in a stronger material overall.

5. Don’t use high-silica aggregates in areas with high humidity

If you’re using high-silica aggregates in areas with high humidity, you may run into concrete failure. This is because the aggregates will absorb moisture from the air, leading to cracks within your material over time.

For example, if you’re creating a sidewalk or patio in a high-humidity area like Louisiana, and you use this sort of aggregate without a waterproof coating, you may be in for a rude awakening.

6. Hire the professionals

Concrete failure is expensive. The best way to avoid it is by hiring the professionals at Port Aggregates.

At PAI, our professional concrete contractors are skilled in creating bubble-free, high-quality pours in high-humidity areas like Louisiana.  We use only the best quality materials for our mixes and never cut corners to save money or time. 

Contact us today to request a quote for your next residential or commercial project!

The post How to Avoid Concrete Failure appeared first on Port Aggregates.

Did you miss our previous article…
https://cedarparkconcrete.org/?p=197

Picture the last food scrap you threw away. Maybe you were dumping some potato peels in the trash, or composting the outer leaves of a cauliflower. Why did you throw it away? Was it for aesthetic reasons? Did you consider any of that food inedible? Did you have patience in that moment to think of a reason to keep it? Were you out of containers to store it in? There are a multitude of reasons why food ends up in the bin, but we hope this article can make it easier to give your food (waste) another chance.

Food waste, as we’ve explored in this series on food knowledge, is one of the most urgent yet avoidable contributors to climate change. Even a single apple that goes to waste due to poor storage strategies or aesthetic imperfections represents a loss of all its embodied energy. That is to say, all the water and land used to grow it, all the energy used to transport and store it, and all of the caloric energy it could have provided to someone are squandered. At such a small scale, it’s negligible, and yet when everyone believes that throwing away food is not a big deal, it leads to enormous quantities of waste that often end up in landfills, releasing methane (a potent greenhouse gas) into the atmosphere.

Reframing Fruit Scraps

One way to reduce food waste is to rethink what you consider food. Of course, this isn’t to say that you should go around eating nut shells and parts of food that leave you with indigestion, but some foods that we are taught to discard have great flavors and health benefits. 

On the most basic level, this applies to fruits with soft peels. Your apple, pear, peach, or nectarine skins can and should be eaten, but certain dessert recipes ask you to peel them, and in those cases, you can enjoy the peel by itself or use it in tea. Beyond those four, kiwi skin adds fiber and flavor when you eat it with the rest of the fruit, and dried pomegranate and hazelnut skin can be pulverized and added to smoothies or sprinkled on meals as a supplement. But fruit scraps don’t just have to be healthy; we highly recommend making treats out of your lemon and orange rinds. Although candied citrus rinds are great dipped in chocolate or sprinkled on cakes, the ones we made were devoured before they could make it to those stages.

More unusually, banana skins make a wonderful meat substitute in some recipes, like tacos or lasagna. Watermelon rinds make good pickles, but they can also be candied by cooking them in sugar syrup. If you make your own milk alternatives at home, you can use the strained almond, oat, rice, or cashew pulp for baking by replacing some of the flour in a recipe with pulp. (Be aware that milk pulp as a flour replacement will have an effect on the moisture and gluten content, so it only works in small ratios of pulp to flour and doesn’t work for difficult pastries, like croissants.) Another unusual recipe we tried was jam made out of passion fruit rinds. By boiling the rinds, taking the skin off, and mashing them with sugar, we cooked a slightly floral and astringent spread that goes well with bread or scones.

Vegetable Scrap Recipes

It’s helpful to rethink how you treat the scraps from your vegetables, too. Make sure not to waste delicious broccoli stalks or beet greens, and definitely don’t throw out the peels of your root vegetables. When a recipe requires peeled potatoes, the peels make a crispy snack or garnish when baked with some oil. Carrot greens transform into a delicious pesto when blended with oil, garlic, sunflower seeds, and salt.

Anything hard to chew can be blended into sauces, as is the case with kale stems and pea shells, and the stems of chard can be pickled. You can even sauté the tough green ends of leeks! The leaves of cauliflower, broccoli or romanesco broccoli should be cooked and eaten as well. Fava pods can be eaten whole, by grilling or sautéing them. When we tried out this recipe, we topped the pods with lemon juice, salt, chili flakes, and mint. 

It should go without mentioning that any vegetable scraps can be made into broth. Herb stems are superb for this purpose, but celery, onions, leeks, carrots, potatoes, and celery root all provide scraps to flavor your broth. Sometimes, there isn’t enough waste to produce broth, so these scraps can be stored in the freezer while you collect enough.

Similarly to broth, parts of some foods can be added to teas or infused on their own. This is most true for leaves, especially artichoke, persimmon, and strawberry leaves, and for dried or fresh citrus rind. 

Other Food Scrap Uses

Food scraps have purposes beyond just culinary! When making a vinegar-based cleaning solution for your house, lemon, orange and grapefruit rinds add a nice aroma. Banana skins serve as aphid repellents when they are chopped up and buried a couple inches deep around the base of a plant, and have anti-inflammatory properties when used on irritated skin. Coffee grounds and oat, almond and rice milk pulp are great body exfoliants, with rice and oat pulp having additional soothing properties when used on facial skin.

Many food scraps can be used to regrow foods, and these experiments double as educational projects as well. Root vegetables can be regrown by placing the tops of the root in water until new leaves begin to grow, at which point they can be planted in soil. Ginger pieces the size of an inch can be planted directly, and in very little time they will grow more ginger. Long, green vegetables such as celery, lemongrass, leeks, and green onions can be regrown by placing one inch of the bottom part of the plant (not counting the length of the roots) in a tray or glass of water until it begins to grow again. They can then be planted in soil. Leafy vegetables such as lettuce or endives undergo a similar process: the bottom parts are placed in water for several days or a few weeks until there is new growth and they can be moved to soil.

Scrap Dyes

We’ve saved the most exciting use for last: dyes! Many fruit and vegetable skins have tannins that help dyes bond well to natural fibers like cotton, linen, wool, or silk. The most well-known dyes made from food scraps are onion skins and avocado pits and skins. Yellow onion skins make yellow and orange dyes, red onion skins create colors between light lilac and deep magenta, and avocado scraps make a pink dye.

These dyes can be made stronger with alum powder, a mordant which helps dyes adhere to fabric better, but they can be used without it as well because of the presence of tannins in these food scraps. Some natural dyes, like the brown colors from chestnut and walnut shells, are vastly improved with the use of a mordant. Pomegranate rinds make a yellow dye and the leaves from loquat trees make a pink dye, both of which work best using a mordant.

Scraps in the Big Picture

Sometimes the scraps from your food just can’t be eaten or used, and that’s okay! When you get to this point, what’s most important is diverting your food waste from the landfill. If your city has a municipal composting program, you may have curbside compost pickup which is an easy way to reduce the emissions of your food waste, but you can also easily set up a compost in your own backyard, or get a small vermicomposting bin for your kitchen. Food waste can also be used to feed a biodigester, which produces biogas that you can use for energy. Both composts and biodigesters are part of our ongoing research at our production center, so you can expect an article soon about the merits and challenges of these systems in an urban setting. And lastly, if you do not have access to municipal or domestic compost where you live, you can see if any farmer’s markets or local gardens collect compost, and bring your food waste to them on a weekly basis. 

When it comes to food, there are so many systemic and cultural barriers to consuming it mindfully and avoiding waste. Overcoming preconceptions about food scraps that are seen as non-food is one part of working against these entrenched cultural beliefs that promote excessive waste. The problem, like any environmental issue, does not come down to just personal choices, but when these small changes are implemented at a wide scale, they can have significant effects, not just in the amount of food that goes to waste, but towards treating the food we have with respect. When we stop taking food for granted, we respect the seasonality of our produce, and stop letting vegetables go bad due to poor storage. You can read about these two related practices in the previous articles of our Knowing Our Food trilogy, and learn about how to preserve food for long or short periods.

The post Knowing Our Food: Scraps first appeared on Critical Concrete.

Though food nourishes us every day, there is still much that we can learn about it. At Critical Concrete, we aim to consume as much local, seasonal food as possible and we have recently started growing it ourselves in our food forest. Unfortunately, it is quite common that we as a society eat food without paying attention to its seasonal availability; it is easy to be influenced by a globalized system that makes practically any food available at any time in the year regardless of climate and the environmental impact. The production of food outside of its peak season can have 3-10 times the emissions as food imported from better climates, so it is important to not only support local farmers, but also to mind the seasonality of fruits and vegetables.[1] While some imported foods, such as almonds and avocados, are imported by boat and have a lower footprint than locally produced options, other more perishable foods are freighted by air, which creates 50 times the carbon emissions as boat transportation.[2] Aside from environmental friendliness, seasonal, local food can be more nutritious and flavorful as it has more time to ripen before harvest, and supports small farms and sustainable farming practices.

That being said, choosing local and seasonal produce means nothing if our food goes bad before we have the chance to eat it. That means that storing food to extend its lifespan is highly important. This research grew out of our curiosity to know more about alternative ways of storing food that are not energy consuming. However, as we encountered more information, the research evolved to focus more on food knowledge, with the aim of informing ourselves and our readers about the needs of our fruits and vegetables and how we can store and consume them. Our upcoming articles from this research will delve into the topics long-term storage, food production, and the use of food scraps, and in this article, we will discuss how to make use of conventional kitchen storage to keep food fresh. 

Food Waste and the Fridge

Food waste is an immense problem that worsens each year. In fact, fighting food waste has been determined to be one of the most urgent solutions to fighting climate change.[3] The production and disposal of wasted food results in water waste, land waste and deforestation, and greenhouse gas emissions. Although a tremendous amount of food waste is the result of industrial food practices, in Europe 42% of food is thrown out by the consumer, and only one third of that food wasted consists of inedible residuals (skin, shells, peels).[4] Regardless of whether climate change can be tackled through individual actions, consumers can still reduce the amount of food lost to spoilage in their own homes. Even if it does not solve environmental issues in and of itself, when we learn about proper food storage and reduce our waste, we save money and take the first steps toward better societal food practices.

At first we were inclined to look for alternatives to our usual house appliances like the fridges, as refrigerants like chlorofluorocarbons (CFCs) are the main cause of the depletion of the ozone layer.[5] This led us to a few methods of long-term storage, which we built as prototypes to evaluate their efficacy in the climate our research lab is located in. Keep an eye out for our next article, detailing these methods and their benefits for different foods and environments.

However, it can’t be ignored that storing food in the fridge and freezer is such common practice, so this article will describe the ways to reduce food waste in the context of conventional storage practices. Thus we first have to analyse the way the fridge is used, to know its strong and weak points and the way it works. Additionally, it is crucial to understand the process of food decay and the science behind it. Once it is understood how food decays, the same principles can be applied everywhere. In order to reach a balance in the system, minimizing waste and prolonging the life of food, we must first know the needs of fruits and vegetables and demystify their storage environments, both artificial and natural.

Where to store different fruits and vegetables

Food Decay

Knowledge about everyday storage of fruits and vegetables is essential. In order to better understand the proper storage of fresh vegetables and fruits, the first step is to clarify the biochemical characteristics and processes which occur after harvesting. This knowledge can help reveal why certain foods become rotten very fast whereas other foods last for a long time. This phenomenon is influenced by two factors: the speed of natural metabolism depending on the specific plant and the way it is stored. 

Enzymes are proteins which serve as catalysts to chemical changes in living organisms and there are thousands of different enzymes with varying functions. Enzymes in our food cause changes to fruit and vegetables which cause them to spoil. In cool temperatures, these enzymes slow their activity, and they can die when cooked above 60 degrees.[6] 

Aside from enzymes, three other rotting agents can reduce the life of food. These are mold, which is visible, yeasts, which convert sugars into alcohol through fermentation, and bacteria, some of which can poison food.[7] Using this information, we can determine how to avoid mold and bacteria, and slow down the process of decay.

Conditions for storage

The best storage method for a given food depends primarily on three parameters: temperature, humidity and ripening.

Temperature: Cooling down slows down the metabolic process and thus has an immense effect on preservation. Nevertheless, there are certain plants, such as bananas, tomatoes, eggplants or cucumber which are very sensitive to the cold and also others which lose vitamins and taste.[8] Moreover you should take into consideration where in the refrigerator to put things. The middle and the back are usually colder than the other areas of the fridge.[9] As there is no cooling on the bottom cold air coming from the middle can warm up and rise up which leads to the different temperatures levels.[10] 

Zones of the fridge and their temperatures

Humidity: Many fruits and vegetables, such as cucumbers, leafy greens, carrots and roots, are susceptible to humidity loss and shriveling.[11] For these, it is important to ensure a high level of atmospheric humidity. Many refrigerators have a crisper drawer for vegetables in order to keep a higher level of humidity. Some vegetables that should definitely be stored in the crisper drawer are spring onions, celery root, spinach, and leeks.[12] Otherwise, vegetables that are susceptible to moisture loss can be wrapped in damp towels and stored in other areas of the fridge.

Ripening: In basic terms, ripening can divide produce into two groups: the kind that continues the process of ripening after the harvest and the kind which abruptly stop ripening when harvested. This fact depends on the natural plant hormone ethylene. Ethylene is a gaseous hydrocarbon (C₂H₄) which speeds up the ripening process.[13] Some fruits and vegetables release ethylene gas in the process of becoming ripe.[14] Others, by contrast, are sensitive to ethylene and absorb it.[15] If you do not want to speed up the ripening and  spoiling effect, try to store ethylene-sensitive vegetables apart from those which release a lot of ethylene. 

Ethylene production and sensitivity in fruits and vegetables

According to their ethylene production, apples, tomatoes, peaches, apricots, avocados, kiwi, mango and bananas should be stored apart from other fruits and vegetables.[16] But you can also make use of this property when you want something to ripen faster. In that case, you purposefully store high ethylene producers together with ethylene sensitive ones.[17] When you have green tomatoes you can store them together with apples in order to get them to ripen faster.      

Referring to proper storage, there are some rules of thumb about food that should never be stored in the refrigerator. Fruits sensitive to cold are pineapples, avocados, bananas, mandarins, mango and melons.[18] Vegetables sensitive to cold are artichokes, tomatoes, potatoes, eggplants, garlic and onions.[19] Nevertheless, there are some real divas who cannot really decide whether they want to be stored in the fridge or in the room. Cucumbers and zucchinis for example are sensitive to cold but if too warm they lose humidity and start to shrivel fast.[19] Therefore, they should be stored in the crisper drawer or in the top part of the refrigerator, wrapped in a damp towel to avoid cold damage and humidity loss.[20]        

Additional Specific Storage Strategies 

With this knowledge of general food storage, we can delve into more specific ways to increase the lifespan of our fruits and vegetables. Berries and cherries are susceptible to mold, so they should not be washed until just before they are eaten.[21] Also, berries are often quite fragile and should be stored in a single layer, if possible.[22] Figs are sensitive to humidity, which makes paper bags good storage containers to absorb their excess moisture, but they can also be stored on plates in the fridge.[23]

As for vegetables, removing rubber bands from the stems is always the first step.[24] Radishes, beets, carrots, and turnips, should be separated from their greens to avoid losing moisture in the roots.[25] Then, the roots can be stored in an open container with a wet towel placed on top.[26] Greens are best in closed containers alongside a damp cloth to keep them from drying.[27] However, you can save room in the fridge by storing kale, chard, and collard greens upright in glasses of water on the counter.[28] Celery and fennel can be stored this way as well.[29] Asparagus is best stored upright in a water inside the fridge.[30] It should be noted that using paper bags, reusable containers, glasses, or damp cloths should make it easy to eliminate the need for any single-use plastic inside the fridge.

Conclusion      

Hopefully, being more cognisant of the needs of fruits and vegetables can limit food ending up in the trash or compost. Now that we understand how the chemical processes happening inside fruits and vegetables cause them to react to different conditions, we can store it in the right way. We can take advantage of the different areas inside your fridge, and organize our fridges to maximize the lifespan of our food. To help adjust to all this new information, we produced a chart to help understand fruits and vegetables and store them in the best way possible. Download it, print it, and put it on the wall in your kitchen! 

In our next article about food we will discuss different ways to store food for longer periods of time and the benefits of each method. Stay tuned to learn how fruits and vegetables can be enjoyed past the periods when they are in season, without forfeiting the nutritional value and flavor of eating seasonal food.

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Bibliography:

[1] https://ourworldindata.org/food-choice-vs-eating-local, opened 8.12.2020.

[2] Ibid.

[3] Hawken, Paul. Drawdown: The Most Comprehensive Plan Ever Proposed to Reverse Global Warming. New York, New York: Penguin Books, 2017.

[4] Principato, Ludovica. Food Waste at Consumer Level a Comprehensive Literature Review. Springer International Publishing, 2018. p. 5.

[5] https://www.conserve-energy-future.com/causes-and-effects-of-ozone-hole.php, opened 8th of December, 2020.

[6] Seymour, John. The Self-Sufficient Gardener: A Complete Guide to Growing and Preserving All Your Own Food. Dolphin Books, 1980. 

[7] Ibid.

[8] https://www.rollende-gemuesekiste.de/wp-content/uploads/Lagertipps.pdf, opened 24.11.2020.

[9] Ibid.

[10] Ibid.

[11] 

[12]https://myplasticfreelife.com/wp-content/uploads/images/Berkeley%20Farmers%20Market%20Tips%20for%20Storing%20Produce.pdf, opened 27.11.2020.

[13] https://www.theproducenerd.com/2018/02/what-is-ethylene-how-is-it-used/, opened 10.12.2020 December

[14] Ibid.

[15] Ibid.

[16] Sächsische Landesanstalt für Landwirtschaft. Verbraucherinformationen Obst Und Gemüse Richtig Lagern, 2003.

[17] https://www.rollende-gemuesekiste.de/wp-content/uploads/Lagertipps.pdf 

[18]https://myplasticfreelife.com/wp-content/uploads/images/Berkeley%20Farmers%20Market%20Tips%20for%20Storing%20Produce.pdf, opened 27.11.2020.

[19] Ibid.

[20] Ibid.

[21] Ibid.

[22] Ibid.

[23] Ibid.

[24] Ibid.

[25] Ibid.

[26] Ibid.

[27] Ibid.

[29] Ibid.

[30] Ibid.

The post Knowing Our Food: Storage first appeared on Critical Concrete.
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Concrete, as the most used building material worldwide has a huge impact on our cities, societies and environment. Much of our research is based on the idea to create an alternative solution for conventional methods of building, such as building with concrete. In this article, we will tackle basic and relevant knowledge and information about concrete, to understand why it is important to think about alternative solutions for the future of our building habits. This write-up will be part of a series of small papers related to meaningful knowledge, to understand why it’s urgent to rethink our conventional building approaches.

Concrete, cement & mortar – definitions

To give a brief overview of what we are talking about in specific, we will first define the most important terminologies that we will need to understand the whole topic around concrete.
Four important terms you should know about and understand their exact definitions: 

Typical composition of concrete

cement  // səˈment

Cement is the key ingredient to mix concrete. This product is mainly made out of crushed limestone mixed with shales and slates, shredded to a fine powder and heated up to approximately 1450°C. The heat causes a chemical reaction, also known as calcination.[1] That reaction along with the heating process causes a high amount of carbon-dioxide emissions, which makes cement production a big driver of greenhouse gas emissions. The entire process happens in a giant mixer, called a cement kiln. [2] The most popular kind of cement is portland cement, developed in England in the early 19th century. [3]

concrete // ˈkänˌkrēt

Concrete is an artificial building material, which consists of a binding agent like cement or lime, in addition to water and aggregates (sand and gravel) as well as potential  additives (like fly ash or plasticizers). The cementitious part gets liquified with water. By adding water to the cement a chemical reaction is caused and the process of crystallization begins. In the next step some additives such as gravel and sand are added. These aggregates are held together by the liquified cement. Once the whole mixture is cured, this process will finish with a solidified product, called concrete.

mortar // ˈmôrdər

Mortar is a workable paste, used to bind bricks, stones or to fill gaps and holes. The basis is made out of a binding agent (such as slaked lime, ash or, most commonly nowadays, cement) added with water and a fine aggregate, mainly sand. 

Mortar is one of the oldest building materials, used for many thousand years. For a long time, slaked lime, volcanic ashes or clay worked as a binding agent. During the nineteenth century portland cement was invented. From that time cementitious mortar rose in popularity and replaced the old binding products.

These two kinds of mortar differ in two ways. On the one hand cementitious mortars usually are more workable due to faster curing, higher water resistance and less cracking, on the other hand non-cementitious mortars significantly cut greenhouse emissions while processing. It even can absorb CO2, which appears to happen when lime mortar cracks, so that air (especially CO2) can be absorbed. By absorbing CO2, lime mortar is even molding and gets even stronger.[4] To put it plainly:  it’s an environmentally friendly and more sustainable alternative.

reinforced concrete // ˈˌrēinˈfôrst ˈkänˌkrēt

In most cases concrete is combined with steel rebars, to compensate for the low tensile strength. The capability of concrete to react on compressive load is ten times bigger than the capability to bear tension loads.[5]

A more advanced and further developed version of conventionally reinforced concrete is prestressed concrete. To make concrete structures more durable against tensile forces, tendons, a high performing kind of rebar gets tensioned. Mainly these tendons are wires or threaded rebars. When applying in the casted concrete, the concrete part gets compressed, which gives the structure a higher performance, while being in service. [6]

Why is cement concrete so popular?

There are many reasons for its popularity: its liquid stone characteristics were revolutionary and created the possibility to make nearly every form out of concrete.

Cement concrete structures can be segmented and precast, making it suitable for big construction projects; and once solidified, it is a very strong material with the ability to bear high amounts of load. Designers adopted the versatile material, and nowadays we find furniture and accessories made of this material, in every kind of shape.

The use of concrete can be dated back to the ancient times. Romans mastered the use of hydraulic lime as a binding agent, called “opus caementicium”. After the fall of the Roman empire, the use of concrete faded, till it got resurrected in the early 19th century. Instead of using hydraulic lime, portland cement, a further development of the ancient version, was invented and led to a big rise in popularity of concrete in building industries. The first buildings during this time were bridges, foundations and harbours, facilitated by the compressive strength and workability of the new material.[7] 

In the late 19th century iron rods, and later steel rebars, were added to poured concrete to increase tensile strength. It was mainly developed by the French Joseph Monier [8]  – an invention which is ubiquitous in building industries nowadays. This invention led to a big rise in popularity in the residential and social housing sector. In comparison to conventional houses in those days, new concrete based housing projects were more durable, termite and fire resistant. The workability of concrete made it fast and easy to use on site. Pre-castable and serial development of construction elements cut costs significantly. In the 50s of the last century, concrete played a major role in evolving the architectural style of Brutalism, a socio-aesthetically driven architecture movement of showing raw, honest constructions often used for big scale civic and public projects. This architectural style was a dominating force during the next two decades. [9]

In addition, the raw materials of concrete are available in large quantities around the globe, which makes concrete cheap to produce. Limestone, sand and gravel are quite cheap. The main processing costs are caused by the cement production. 

What quantity of resources are needed to produce cement concrete?

There are four main components of cement concrete (cement, water, sand and gravel). For reinforced concrete, there is an additional component – steel. Besides these materials, there are more raw resources needed to produce the main ingredients. To produce one tonne of cement, approximately two tonnes of raw limestone are necessary. [10] The production of cement is a high energy consuming process. One ton of cement takes about 120 kWh of energy in process heating. This energy is mainly obtained from fossil fuels and burning waste. [11]

The cement concrete recipe

There are several different recipes for making concrete. The recipes mainly differ in the ratio of cement and the added aggregates. Concrete can be mixed with different ratios to get a higher load bearing capacity or to get a higher ability to withstand different exposures, such as seawater, moisture or frost.

The following recipes just give you a basic overview about how a classic mixture of concrete could look like:
A standard concrete mix consists of 1 part water (7,7%), 2 parts cement (15,4%) , 4 parts sand (30,7%) and 6 parts gravel (46,1%). [12] 

The higher the load the more cement you’ll need (f.e. a concrete column, foundation needs 1 part water (11,1%), 2 parts cement (22,2%), 2 parts sand (22,2%) and 4 parts gravel (44,4%) ).
Around 70% of the built concrete constructions are reinforced with steel, so you would usually have to add a certain percentage of steel rebars to the produced concrete (60-80 kg/m3 of concrete).[13]

That means a ton of average concrete consists of:

77 kg of water (7,7%)154 kg of cement (15,4%)307 kg of sand (30,7%)461 kg of gravel (46,1%)

Components of 1 tonne of concrete

Where is concrete used?

The use of cement concrete has various fields of application in construction and design. Since it was developed in the early XIXth century as a powerful structural material, it can be found in several constructive elements. The constructive elements made out of concrete can be summed up in three main categories:

massive built horizontal and vertical load bearing elements such as foundations and walls, used for small to middle scale buildings, such as residential housing.filigree skeleton construction elements, such as pillars and beams, mainly found in high rise buildings and large scale commercial buildingsspecial construction elements for infrastructural and exceptional building typologies, such as bridges, tunnels, dams or bunkers.

Where is concrete useful?

Nowadays concrete is used in many different ways. All constructive elements can be made in concrete and in most cases they are realized with this material.
But is it really necessary to replace other common construction methods with concrete?
It makes sense to use concrete in constructions, where load bearing elements have to bear big compressive strengths. A high rise a few hundred meters high? A tunnel? A dam? For sure! – There are fields of application, where no other material performs as well as concrete but in many cases concrete is used in small scale projects, where it is unnecessary and over proportioned.

How sustainable is cement concrete?

Concrete is certainly one of the building materials which gives a nearly unlimited range of use. As mentioned before, there are many upsides to using concrete. But there are always two sides of the coin.

A general definition for sustainability is meeting the needs of the present without compromising the ability of future generations to meet their needs. Sustainability is often discussed in environmental terms. It can also be related to two other important topics: society and economy.

Obvious and hidden impacts on our environment

Pie chart comparison between countries CO2 emissions and cement production

The impact on our environment caused by the cement industry and by building with concrete is enormous. The production of cement is a high energy consuming process. This energy is mainly obtained from fossil fuels or burning waste [14] In addition the chemical process of producing cement releases one molecule of carbon-dioxide per each molecule of calcium silicate hydrate. For each ton of produced cement, one ton of CO2 is emitted just by chemically processing it [15] Besides the vast amount of carbon dioxide emitted, many other hazardous air pollutants such as NOX or PM10 are emitted during the process. [16]

Cement is just one part of concrete. The added aggregates, such as gravel and sand, are mined in humongous amounts to cover the demand of concrete industries. Many environmental systems are suffering from negative effects such as land loss by erosion, destruction of natural habitats, sealing and contamination of soil. Some of these aggregates, especially sand, have to be shipped around the world to service demands. [17] Just to give a short glimpse of one of the biggest cruxes in world of the concrete industries – new developing middle-east states, such as the United Arab Emirates or Qatar have to import big amounts of sand to service their huge demand in building industries, despite the fact that cities like Dubai or Qatar are located in the middle of sandy deserts. [18] However, not all of the sand we can find on the globe is suitable for concrete production; desert sand is too fine and round to be used as an aggregate. [19]
Furthermore, concrete production is a thirsty industry. It needs almost 10% of annual industrial water withdrawal, and 75% of the concrete production takes place in regions which are already facing water stress and drought. [20]

Beside this, the impact on society has to be emphasized. The internationalization of architecture and modern building technologies have a negative influence on vernacular building technologies and local architecture. New buildings tend to be built in a modern way with modern materials, such as concrete. Cost efficiency, the establishment of new building technologies and the time aspect are reasons for a significant decrease of traditionally built projects. 

Impact of globalization and industrialisation on building traditions.

Comparison between the use of concrete and other building materials

One of the main issues caused by that situation is the loss of building knowledge and traditions. Traditional building techniques are being replaced by modern approaches. Around the world, houses and cities have been built according to local tradition for centuries. Now, knowledge that was gained in a long and enduring process is about to get lost in a few decades. 

Main drivers for the loss of vernacular architecture are caused by the growing globalization and industrialization of the world. Innovations in building technologies can be spread easily around a fully connected world. Rare materials not locally available can be easily shipped from anywhere – and they get transferred in humongous amounts around the planet. 

Downcycling cement concrete

The economic sustainability of concrete is always mentioned as a big pro. Nonetheless there are a few facts which are not properly taken into consideration. The production of concrete is cheap in comparison to other materials. A main reason for this, is that the aggregates you need to mix concrete are available in large quantities almost everywhere around the planet. But in recent times the local availability of certain components, such as sand are diminishing. [21] Our resources on the planet are finite, so using and monetizing resources as if they are infinite is unsustainable. To address this, the concrete industry tries to emphasize their product as recyclable, but to make it clear – concrete is not recyclableRecycling means, returning a material into a previous stage of a cyclic process. In case of the mentioned material, this is not completely possible. During calcination, the processing of the raw resource of limestone comes to a point of no return. Once cement is made, the process is irreversible. There is no commercially viable process to recycle it.[22] Recent reusing methods of concrete consist of shredding it and mainly using it as gritting material for infrastructural projects. In some cases this crushed concrete can be used as an aggregate to partly substitute gravel in concrete. Nevertheless these substitutes are small in numbers and in the end new concrete still requires additional water, cement, sand and gravel [23] Technically, the recent approaches to recycling concrete can be better named downcycling processes or a kind of mitigation. Many experts criticize the bigger potential of reusing shredded concrete for new concrete projects, [24] an effort which should be broadened in the future. 

Contradictive durability of concrete structures

Many proponents often mention concretes’ durability as a big pro. The use of concrete without adding any other materials (such as rebars, made out of metal) technically creates a very durable building material. Despite, most of the applied concrete is reinforced to be able to react on tensile stress. But the application of reinforced concrete in terms of durability is a contradiction in terms. Here nature inevitably can shorten the life span of buildings built out of reinforced concrete. Due to different thermal expansions and the inevitable inheritation of oxidation of the used steel rebars, concrete constructions suffer fast deterioration during their lifespan. Recent studies have shown that there is a 50% chance of reinforced concrete structures to not fulfill their service in terms of load bearing after just 35 years of use. [25]

What can be used instead of cement based concrete?

Concrete as a kind of fluid stone has found use in all fields of construction. But is it always necessary to use concrete? There are new materials and also tried and trusted methods of building which have mostly been replaced by concrete solutions. The replacement of conventional portland cement based concrete can cut greenhouse gas emissions and other environmental impacts significantly. Basically there are two main ways to avoid a humongous use of classic portland cement based concrete. The first one is to substitute or avoid the most polluting ingredient of classic concrete, portland cement. In a second scenario different building approaches with alternating materials or other building techniques can be applied.

Cement substitutes

First of all, portland cement based concrete mostly can be substituted by pulverized fly ash (PFA), which is a side product of coal burning processes. Another substitute with a big potential is Ground Granulated Blast-furnace Slag (GGBS), which is able to replace portland cement up to 90%. GGBS substituted concrete sets more slowly than concrete made with ordinary portland cement. The higher the amount of GGBS in the cement mix the longer it takes to cure. Besides this, a positive side effect of using GGBS substituted concrete is that it continues to gain strength over a longer period leading to improved overall durability and life expectancy. [26] Nevertheless the mentioned substitutes are by-products of other industries, such as coal, steel or aluminium production, which also have an enormous negative impact on our environment.

Green concrete

During the last decade several scientists started working on green alternatives for concrete. The most advanced approaches use micro organisms such as algae, bacteria or fungi for biocement production (CaCO3) by using the metabolic activity of these microorganisms. [27,28] Some of these bioproducts achieve similar specifics as classic portland cement and present a feasible and viable alternative to conventional portland cement based concrete.

lternative construction methods

Besides an ingredient-related replacement of conventional concrete, there are many tried and trusted construction methods which were applied in vernacular building styles and local architecture traditions. There is no convincing evidence that justifies concrete as the ultimate building material for most building tasks.

This table aims to present a series of more ecologically friendly solutions for common uses of cement concrete:

construction elementclassic building material
to be replaced / substitutedeco friendly alternative (not exhaustive)foundationsreinforced concretetyre foundation (for point foundations) [29]
gabion foundations [30]pillarsreinforced concrete
steelwooden constructions (bamboo, pine, GLT – glue laminated timber)
cardboard tubeswalls(reinforced) concrete
bricks
steel sandwich panelswooden constructions (CLT – cross laminated timber, framework constructions)
rammed earth (clay)
hempcrete
bricksflooringcement based screedclay 
wooden planks roofsreinforced concrete (flat roofs)
steel sandwich panelswooden constructions
thatched roofs
green roofs
hempcretepathingcement based pavement
asphaltnatural stone :
cobblestone, granite plastergypsum based plaster
cement based plastercardboard + lime plaster [31]
hempcrete plaster
straw clay based plaster

Conclusion

Concrete plays a major role in building industries. The further development of newly industrializing economies with huge demands on concrete are driving the ongoing trend of a growing concrete industry. Beside its advantages and big popularity, concrete brings a lot of negative impacts on global warming, environmental systems, building culture and social city development. It is important to mention that concrete lacks recyclability. The present system around the concrete industry can be summed up as a cradle-to-grave system. Resources are extracted, used and then wasted and dumped or downcycled in the best case scenario. Due to the chemical process, cement, the most important ingredient of conventional concrete, will never be recyclable, which underlines the unsustainability of a whole industry. Its fast and wide availability and low costs in production make it popular for many large scale projects. 

Nevertheless there are recent approaches to develop more sustainable alternatives to the classic portland cement-based concrete by trying to avoid or minimize the use of cementitious components, aiming for a better reusability and recyclability of resources. 

In addition, investigating forgotten vernacular solutions reopens fields of research to move forward to a more environmentally respectful architecture. Stay tuned on our continuous research, on social media and if you can and feel like supporting the initiative, make a small donation on our Patreon! 

Sources

[1] https://www.sciencedirect.com/science/article/pii/B978008034720250023X , opened 12.08.2020

[2] https://www.britannica.com/technology/cement-building-material/Extraction-and-processing , opened 12.08.2020

[3] https://www.screedscientist.com/portland-cement-a-brief-history/ , opened 18.08.2020

[4]  Quantitative Analysis of CO2 Uptake and Mechanical … – MDPIwww.mdpi.com › pdf , opened 23.09.2020

[5] https://diglib.tugraz.at/download.php?id=576a7195cc9f9&location=browse , opened 11.08.2020

[6] 372R-13 Guide to Design and Construction of Circular Wire-and-Strand-Wrapped Prestressed Concrete Structures , 2013

[7] Historic Concrete in Scotland Part 1: history and Developmentpub-prod-sdk.azurewebsites.net › api , opened 13.08.2020

[8] https://www.britannica.com/biography/Joseph-Monier , opened 13.08.2020

[9] https://www.architectureanddesign.com.au/features/list/a-look-at-brutalist-architecture , opened 20.08.2020

[10] http://ecosmartconcrete.com/?page_id=208 , opened 12.08.2020

[11] https://global-recycling.info/pdf/GLOBAL-RECYCLING_2-2019 , opened 11.08.2020

[12] https://www.marshalls.co.uk/gardens-and-driveways/blog/how-to-mix-cement-to-make-mortar-or-concrete

[13] https://diglib.tugraz.at/download.php?id=576a7195cc9f9&location=browse , opened 26.07.2020

[14] https://global-recycling.info/pdf/GLOBAL-RECYCLING_2-2019 , opened 11.08.2020

[15] http://ecosmartconcrete.com/?page_id=208 , opened 12.08.2020

[16] http://ecosmartconcrete.com/?page_id=208 , opened 13.08.2020[1] http://ecosmartconcrete.com/?page_id=208 , opened 13.08.2020

[17] https://www.globalconstructionreview.com/news/shifting-sands-concrete-hungry-singapore-orders-mi/ , opened 28.07.2020

[18] https://www.bbc.com/worklife/article/20160502-even-desert-city-dubai-imports-its-sand-this-is-why , opened 19.08.2020

[19] https://www.bbc.com/worklife/article/20160502-even-desert-city-dubai-imports-its-sand-this-is-why , opened 19.08.2020

[20] https://www.nature.com/articles/s41893-017-0009-5.epdf , opened 26.07.2020

[21] https://www.globalconstructionreview.com/news/shifting-sands-concrete-hungry-singapore-orders-mi/ , opened 29.07.2020

[22] CSI-RecyclingConcrete-FullReport.pdf , opened 29.07.2020

[23] https://www.archdaily.com/933616/is-it-possible-to-recycle-concrete, opened 30.07.2020

[24] https://eu-recycling.com/Archive/22163 , opened 30.07.2020

[25] https://www.structuremag.org/?p=9459 , opened 18.08.2020

[26] https://www.greenspec.co.uk/building-design/concrete-cement-substitutes/ , opened 25.08.2020

[27] https://www.mdpi.com/2071-1050/10/11/4079#abstract , opened 25.08.2020

[28] https://www.sciencedirect.com/science/article/pii/S2215017X18302923 , opened 25.08.2020

[29] https://criticalconcrete.com/tyre-foundations/ , opened 25.08.2020

[30] http://bristolgreenhouse.co.uk/site/foundations.html , opened 25.08.2020

[31] https://criticalconcrete.com/out-of-the-box-vol-3/ , opened 25.08.2020

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In the former articles was explained some of the advantages to be found within these ancient  common methods of charring wood. Historically and within many cultures, there are a myriad of charring modalities. In this article you will find adapted and illustrate one of those methods using a small wood burning flash oven that can effectively provide the charring levels needed without overtly case timber that has been dried too rapidly. This leads to reversed stresses; compression stresses on the shell and tension stresses in the core. This results in unrelieved stress called case hardening.[1]) the wood items placed through it. In this article we explain how our charring station is built and how it works. Charring systems like this one have been commonly found in many cultures and this is an adapted version of several of those [2]. It is adaptable, is easy to operate and runs without the use of gas or special tools. All that is needed are some (fire) bricks and scrap wood for fuel.

Counter-intuitively, charring wood has several astonishing advantages without involving any chemicals or additional energy consumption. The idea is to sear the surface of the wood without combusting the whole piece nor damaging the interstitial aspects of the wood so it will not warp over time. Besides giving the material an interesting and unique look, the process leads to a triple protection, all without the need of repeating the process after some time has past:

fire protection – charring the surface starts a superficial carbonation of the material and thus lowers the thermal conductivity. termite and mold protection – charring wood destroys the wood’s nutritional value to insects and fungi.water protection – the enhanced carbonation gives the charred layer a waterproof resistance, as water slips on burned wood like over an oily surface.

The easiest and most popular way to char wood commonly found today is probably with a blow torch. This can work, but regrettably too often performed without the attention to detail not to stress the wood from within. It’s easy and practical,  especially for small or irregular pieces but has to be performed with caution. But when searing many big wooden pieces it is slow and uses a lot of gas. These searing modalities are not to be confused with traditional Japanese, 焼杉 (Yakisugi) which is often misrepresented as 焼き杉 (aka shou-sugi-ban”) [3] – us included, in our previous articles!.

Yakisugi can only be achieved with a limited range of Cypress species found on the islands of Japan[4] and is a very unique process found within several methods of crafting guilds. The most commonly seen being where three planks of wood get bound together to form a long triangle and a fire is started in the resulting tube. There are several other methods, but they are for very specific formats and within context to only yakisugi and not the charing modalities found within other cultures.This technique works well only when you have similar boards, as it’s complicated to set up when boards have different widths and lengths.

Terunobu Fujimori, Tea House, Barbican. Photo Ben Tynegate

The birth of the charring station

This contemporary oven is based on some of the principles of a rocket stove. The main idea is to create a fire within a brick tube, which will become very concentrated and strong due to the tube-generated draft-effect (for more explanation on this and general information, check our articles on rocket stoves). Just over the burning material, where the fire is very strong, there will be small slots on the opposing sides of the tunnel. The wood, which needs to be seared, can be passed easily through the fire and thus be charred fast and safely.

After this oven was created with commonly available materials which enables us to char planks and boards of different sizes in an effective manner. This oven also allows the operator safety by lowering the risk of burning their hands, while also providing more control of searing the wood and less waste of fuels which is then more environmentally friendly.

How does the charring station work

Author: Melana Jäckels

1 – The main part is a L-shaped tunnel. On the bottom it has an opening on the side, where the air goes in and it flows all the way through the tunnel up to the upper opening.

2 – Right after the curve, the fireplace is based on a second layer. Its bottom has two small gaps for the air to pass and to allow the finer ash to fall.

3 – It is important to have a tunnel that is at least 5 cm wider than the boards you plan to char. If a board fills the whole wide of the tunnel it stops the draft and decreases the fire.

4 – On the same level as the fire is also the stair-like firewood intake. The fire is started and fed from here. It’s important to have a brick to close the firewood intake so it does not disturb the air draft in the moments no wood is inserted.

5 – In the chimney, right above the fire, there are two vertical slots on opposing sides to insert the wood you want to char.

6 – Above the inserting slots the chimney narrows slowly. This is important to not happen in a sudden step, as it otherwise will decrease the draft and create a lot of smoke coming out of every small gap.

Building your own charring station

For our charring station we used 12 big bricks (ca. 29x18x9), around 70 medium-sized, red bricks (ca. 23x10x7) and 5 fireproof bricks (22x10x2). Depending on what is available, numbers and materials might be adjusted. Before starting the building process, it is important to choose a big outside space, which is not too windy and has a relatively leveled ground, with enough space on each side of the station to pass the board through.

Step by step:

First, we made a fire-resistant base which is leveled and flat. For this we used the big bricks

Afterwards we started to build a tunnel for the air intake with dimensions of 90 to 25cm. It is important that it is stable and possible to close with removable bricks on the sides

We covered the tunnel with the red bricks and left two gaps of about 1,5 cm each as seen in the picture.

The fireplace gets covered with fireproof bricks and the next line of bricks is put on all sides

To protect the walls, we also placed fireproof bricks around the fireplace

The next step is to build the J-shaped intake with steps made of bricks, towards the fireplace. It is important to make sure its height will match up with the next row of bricks

Now it is time to create the slots where the to be charred boards will be inserted. For that we put two bricks flat across from each other. This  station works  well for boards with a maximum width of 16 cm. If you plan to use a roller stand, make sure the height of your slots measured from the ground is adapted to the height of the roller stand)

Above the slots we continued building the chimney in the original diameter for a few more rows, but then we start to become narrower by changing the order of the bricks

In this timelapse video you can see how we built up the station in 10 seconds!

How to use the Charring Station

Before starting, make sure to have the right equipment (fire resistant gloves, a mask, a bucket of water / sand, and a fire extinguisher) and enough material to burn! If you want to char a big quantity of wood it is also quite handy to have rolling stands.

Starting the fire works best when you build a little teepee out of dry kidlings and put some sawdust on it, light up the tip of a rolled paper (A4 is enough), and move it slowly into the directions of the teepee. Besides you can put another burning paper over the chimney, to facilitate the draft-effect.

To avoid unnecessary interruptions, it is important to have a constant refilling of firewood. As soon as the fire burns strongly, the opening of the firewood intake can be closed and the boards can be inserted through the slots. Inside, the strong and concentrated fire will char the surface of the wood from below and the sides. The boards should be pushed through the fire in small steps to have a satisfying and regular result. After the first part of a board is charred, it can be taken out and pushed upturned through the fire again until both sides are completely charred. If the results are not satisfying, the pace should be adapted. Depending on the size, form and species of the wood it will take its respective time to finish one piece.

Once the board is charred it should be brushed with a metal brush and oiled. As the charring process dries the wood very rapidly, depending on its nature it might have a tendency to crack. The linseed oil will nurture the wood and compensate for this effect. For more information on this see our article on Natural Wood Protection.

Conclusion

We are using this method for a while now and we are super satisfied with the results. Not only we save time but also we are more independent of gas. The work with the charring station is safe and convenient. The station is easily adaptable and can be modified to different dimensions. We are looking forward to using the station in the future and improving it further.

Check our YouTube video for a step-by-step tutorial how to build up your own station!

We would like to sincerely thank Jay C. White Cloud for his time, valuable input and collaboration on this research.

Sources

[1] Wikipedia “Wood drying”, [Online] available at https://en.wikipedia.org/wiki/Wood_drying (Last accessed in July 2020)

[2] Jay C. White Cloud [Tosa Tomo Designs] https://about.me/tosatomo

[3] [4] Nakomoforestry “Yakisugi” Or “Shou Sugi Ban”? Learn What You Should Call It, And Why”, [Online] available at https://nakamotoforestry.com/yakisugi-or-shou-sugi-ban-learn-what-you-should-call-it-and-why (Last accessed in July 2020)

Picture: Terunobu Fujimori, Tea House, Barbican. Photo Ben Tynegate [Online] available at https://www.ben-tynegate.com/tea-house (Last accessed in July 2020)

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