A concrete mixer (often colloquially called a cement mixer) is a devicethat homogeneously combines cement, aggregate such as sand or gravel, and water to form concrete. A typical concrete mixer uses a revolving drumto mix the components. For smaller volume works, portable concretemixers are often used so that the concrete can be made at the constructionsite, giving the workers ample time to use the concrete before it hardens. An alternative to a machine is mixing concrete by hand. This is usuallydone in a wheelbarrow; however, several companies have recently begunto sell modified tarps for this purpose
