What is the difference between cement and concrete?
Cement is actually an ingredient of concrete. Concrete is basically a mixture of aggregates and paste. The aggregates are sand and gravel or crushed stone: the paste is water and Portland cement. Cement compromises 10 to 15 percent of the concrete mix.
What does it mean to “cure” concrete?
Curing is one of the most important steps in concrete construction, because proper curing greatly increases concrete strength and durability. Concrete hardens as a result of hydration: the chemical reaction between cement and water.
What is air-entrained concrete?
Air-entrained concrete contains billions of microscopic air cells per cubic foot. These air pockets relieve internal pressure on the concrete by providing tiny chambers for water to expand into when it freezes.
Why does concrete crack?
Concrete, like all other materials, will slightly change in volume when it dries out. In typical concrete this change is about 1/16 of an inch in 10 feet. The use of joints is recommended to allow for the difference in volume changes due to shrinkage.
Why do concrete surfaces flake and spall?
In areas of the county that are subjected to freezing and thawing the concrete should be air-entrained to resist flaking and scaling of the surface. If air-entrained concrete is not used, there will be subsequent damage to the surface.
Another main reason for flaking and spalling is salt damage. Whether it is the salt from the streets that you drive on and then track it on to your driveway or the salt you put down yourself to melt the ice. This will damage your concrete.
What is a 3,000 pound concrete?
It is concrete that is strong enough to carry a compressive stress of 3,000 psi after 28 days.
How to protect your concrete surface?
The first line of defense against chemical attack is to use quality concrete. The second line of defense is the application of a good quality sealer which will keep your concrete from absorbing spills.