Maybe you’ve heard from our blog or somewhere else that precast concrete lasts a long time. Now, this might lead you to the question: just how long does it last? 10 years? 30 years? 100 years? The short answer is concrete has a life span of around 50 to 100 years – but there’s a catch.
Precast Concrete Must Be Built Right to Last
The quality and durability of concrete products depend a lot on the way the product is made. Why? Well, concrete goes through a curing process. During curing, the concrete dries and hardens.
In a perfect world, concrete would always cure at the right temperature and moisture level. The ideal level is around 80% to 85% moisture and 50 degrees Fahrenheit.
In reality, concrete is poured in whatever conditions are available to the workers. There is a limit to how high and low the temperature and humidity can be, but this range is pretty large.
For most projects, it’s most important to just get the job done. But this makes for concrete that can’t reach its full potential.
In conditions that are too hot, wet, cold, or dry, the concrete cures too fast or unevenly. In this case, since concrete shrinks as it cures, the uneven curing could cause internal stress and micro cracks. These cracks severely limit the strength of the concrete.
What makes precast concrete different? Well, precast concrete is built in as near a perfect environment as we can get.
Since precast concrete can be built indoors, we get to control the humidity and temperature. When the temperature is ideal, we can create the best possible product.
We also get to inspect every part that leaves our warehouse. If it doesn’t meet our standards, we don’t ship it out.
With cast-in-place concrete, replacing weak parts isn’t that easy. This often results in poor products being used because the process of removal and replacement is too much.
Increase Strength and Durability Through Additives
Many precast concrete manufacturers have been adding additives to the concrete to increase its strength and durability.
The additives help raise the compressive strength while still maintaining low water to concrete ratio. How does it do that?
In general, the more water added to concrete, the weaker the end product will be. But, since precast concrete has lots of small cracks and narrow spaces for the concrete to flow through, it benefits the quality of the final product to have more easily flowable concrete. Otherwise, the concrete can’t reach those hard-to-reach places in the forms.
We used to increase the water content, which limited the strength. Now, the use of additives helps make the concrete flow more efficiently without extra water. So, we end up with a higher quality product, with a much higher strength than was possible without additives.
How much has this increased the strength? When precast concrete was first invented it was common to get a 28 day compressive strength of 3,000 psi. Now 28 day compressive strengths can get as high as 6,000 psi. And the concrete mix designs are making advancements that could reach strengths even higher than that.
What does this mean for the lifespan of precast concrete? The higher the strength, the longer the product lasts. We could soon see precast concrete with a standard life span that is longer than 100 years.
Contact us today to get a free estimate. We can’t wait to help you bring your projects to life.