Concrete contains sand, gravel, and cement, and is used for a variety of finished products such as foundations, sidewalks, and road surfaces. 

Cement contains a special hardening ingredient (a gray powder) that makes it harden.

Like all other materials, concrete will slightly change in volume once it dries out. Joints are put into concrete pavements and floors to allow it to crack in a neat, straight line at the joint when the volume changes due to shrinkage.

Concrete is measured by the cubic yard. Therefore, concrete that measures 3 feet x 3 feet x 3 feet is 27 cubic feet. A cubic yard of concrete will weigh approximately 4,000 pounds. To determine the amount of concrete mix you need, simply use the Roadrunner Ready-Mix calculator. This will ensure that you have the right amount of concrete for your upcoming project.