What is concrete?
The most widely used man made product in the world, concrete comes only second to water as the worlds most consumed resource. Concrete provides the literal building blocks for homes, transportation, and water systems. It is essential for healthy living.
What is cement?
Cement is a fine powder that is made by first crushing and heating limestone along with clay or shale. The milled raw materials are then fired in a rotating kiln. The cement emerges from the kiln as a powdery material; that is the glue which binds the ingredients of cement, water, and aggregate, resulting in concrete.
How much concrete to use?
Measure the length and width that you’d like to cover. Multiply the length by the width to determine the square footage. Convert the thickness from inches to feet. Multiply the thickness in feet by the square footage to determine the amount of concrete you will need to order in cubic yards, the standard measurement by which contractors order concrete.
Why does concrete crack?
Concrete, like all other materials, will slightly change in volume when it dries out. In typical concrete this change amounts to about 500 millionths. Translated into dimensions-this is about 1/16 of an inch in 10 feet. The reason that contractors put joints in concrete pavements and floors is to allow the concrete to crack in a neat, straight line at the joint when the volume of the concrete changes due to shrinkage.
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. However, hydration occurs only if water is available and if the concrete’s temperature stays within a suitable range. During the curing period (from five to seven days after placement for conventional concrete) the concrete surface needs to be kept moist to permit the hydration process. New concrete can be wet with soaking hoses, sprinklers or covered with wet burlap, or can be coated with commercially available curing compounds, which seal in moisture.