Concrete is everywhere. In fact, concrete is the most-used building material in the entire world. When you compare the amount of concrete tonnage used to other materials, more concrete is used than wood, plastics, aluminum, and steel combined. So if so much of it is used, why are crumbling foundations still a thing? If concrete is a multi-billion dollar industry, why are foundations still cracking and falling apart?
As strong as concrete is — concrete buildings from thousands of years ago are still standing, and they didn’t even have rebar — there are still situations in which it can crumble. Sometimes this happens right away, and other times it takes decades. People everywhere can have concrete foundation problems, and it’s often affected by the knowledge and experience of the concrete contractor. Today we’re going to take a look at the most common reasons that crumbling foundation occur, and talk about house lifting and foundation replacement can help.
Facts About Concrete
Before we talk about why concrete fails, we think it’s important to describe what concrete is. Knowing a bit more about it can help you understand the points below when we tell you how it fails.
Concrete is a composite building tool, meaning that it is made up of more than one material. While there are varying extras added to concrete in order to make it proprietary, it is typically made up of:
- A coarse aggregate – The basis of concrete is a coarse substance, usually rock and sand.
- Cement – Cement works as the binding and hardening agent that keeps the coarse material bound together.
- Water – Water activates the cement dust and chemically joins with it.
There are two things to keep in mind. First, concrete is sometimes mistakenly called cement, even though cement is just one component of concrete. Second, cement does not dry; it cures, meaning that the water molecules continue to bond with the cement molecules over time. Most of this curing takes place in just a few days, but can continue to happen for decades after the concrete is poured.
What Can Go Wrong?
So, with just three standard ingredients, it doesn’t seem like much could go wrong. Indeed, most concrete lasts for decades before some outside force causes it to crack. But there are a few specific problems that can make concrete weaker. Let’s take a look.
Incorrect Ingredient Ratios and Mixing
While most people don’t mix concrete, many of us have baked a cake. If you put too much water in, it’s going to be too soupy. If you don’t mix it properly, there’s going to be patches of flour. And if you’re at a high altitude and don’t follow the high-altitude directions, the cake isn’t going to rise properly.
Similar problems can arise with concrete mixing. When mixing concrete, it’s very important to get the right amount of each material. Yes, there are only three basic ingredients in concrete, but these ingredients may have to be altered considering the weather, the amount of reinforcement used, the turnaround time until building begins, the soil conditions, and the type of building that will be built upon the foundation. Getting any of these wrong could result in foundations that will eventually crumble.
If you remember middle-school science, there are many ways to get water to evaporate more quickly than it usually would. You can increase the temperature, increase the surface area, or, in the case of wind, blow air across the surface.
The ratio of water in the mixture is vitally important to how concrete cures. Unfortunately, high winds can cause the water to evaporate before it can bond with the cement. This often affects the top layer of the concrete most, which wouldn’t be a problem except that that’s the part of the concrete on which the foundation of a building rests! If winds are too great, it’s possible that the pouring of the concrete will have to be delayed.
Rain can cause the opposite problem that wind presents: too much water. Again, the ratio of cement to water is very important, because the water needs cement to bond with. If rain introduces too much water into the wet concrete mixture, the concrete could be considerably weaker than concrete poured with the proper mixture of water.
The amount of time it takes to show problems will vary depending on the point the mixture was at when it started raining. If most of the concrete is cured and the water only penetrates the topmost layer, you could get surface scaling. Surface scaling makes the uppermost layer of the concrete crack, which exposes the underlying parts and allows water to settle in the rougher grooves of lower layers.
In general, concrete shouldn’t be poured when rain is predicted. Unless the area can be completely protected by tarps, it’s best to delay the concrete pouring until the weather cooperates.
Temperature plays a bigger part in how concrete cures than most people realize. When the weather is too hot, water evaporation can lead to surface shrinkage and the problems we discussed above.
When it’s too cold, the curing time increases exponentially. For instance, a 70-degree day is just about perfect for pouring concrete. But if you drop the temperature just 20 degrees, it’s going to double the amount of time it takes to cure. Drop it another 20 degrees and the water freezes!
In general, this increased time doesn’t harm the concrete (unless the water does freeze). But problems do show up when the foundation is used too soon after it’s poured. For instance, if you have your house lifted in order to build a new foundation underneath, you don’t want to rush the process of setting it back on the new foundation if it’s been cold out.
Contact Payne Construction Services To Replace Your Foundation!
These aren’t the only problems that can affect concrete and lead to crumbling foundations, but they are some of the most common reasons that concrete fails. A good concrete contractor will know how to adjust for the problems we mentioned above, and know when — and when not to — pour the concrete.
If you have a crumbling foundation and need a new one built while your house is lifted, Payne construction is ready to help. Contact us today with questions or to get the process started!