Ancient Roman Concrete’s Durability Finally Explained
I actually work for a cement and concrete manufacturer. I was thinking more along the lines of roads and large buildings in my comments above.
For individuals, I completely agree with you that stronger foundations and floors in homes would be a good thing. The problems of energy to generate heat and cost of transporting the materials are still there. But because it is on a much smaller scale it MIGHT be easier to overcome.
Availability of quick lime might be an issue, as well. At least in some locations.
For pouring a driveway or a garage floor though…I’m still not sold on it.
“Strength” for concrete is a measure of compressive force. It’s measured in PSI. Unfortunately, even a very high PSI concrete can break if its support is somehow undermined. The biggest thing for homeowners is making sure that the foundation is done properly with the correct support around the concrete and diverting water away so that it is not washing or damaging the support in some way.
That being said, there are several methods to avoid the kind of cracks you’re talking about. For anyone reading this… make sure your builders include rebar in your foundations. This goes for driveways, too, although it doesn’t have to be rebar in this case… a simple wire mesh or wire fence laid in the concrete (especially if you’re DYIing it) is probably enough. There is also a fiber that can be added to decrease the likelihood of cracks in driveways, etc. but that’s more for if you’re paying someone to do it. I don’t know that you can buy that kind of concrete unless you’re dealing directly with a seller with the mixer trucks and stuff.
You can also increase the thickness of the concrete. This adds significant cost, but a 9 inch thick driveway would be better than a 6 inch thick driveway. There is a diminishing return here though. Once you get to a certain point, the additional cost is not worth the additional “protection.”
For a foundation, especially, make sure they dig deeply enough to get good ground underneath the concrete. This is one thing I had to be careful of when we built our home. We have horrible dirt. I know it sounds funny, but the kind of dirt we have in this area is really bad for settling. It simply compresses too easily so the weight of a house is going to cause it to settle quickly. I had to make sure that the contractor building my foundation dug deeply enough to get past more of the bad stuff before putting in gravel and pouring concrete. I was fortunate in that the contractor was already doing this which made me feel good about using him for some other projects I had associated with the house.
Finally, do anything you can to ensure proper drainage. Water will erode soil even under your home or driveway or cause the soil to settle.
One thing I learned when I joined my current company is that there are hundreds of “recipes” for cement and that many more “recipes” for concrete. (Cement is essentially the “binder” that holds everything together in concrete.) I don’t know that anyone realized exactly how the Romans did it, but I do know that the manufacturers have MANY “levers” they can pull in order to achieve varying strengths and curing times. They are also constantly testing and experimenting with different additives and other cementitious (It’s a real word… honestly) materials in an effort to lower costs without sacrificing strength, etc.
It was more interesting than I thought it would be, honestly.