The Aggregate in Concrete

The Conco Companies offer a range of services that include quality concrete formwork, reinforcing, place and finish, and shotcrete.  We also own a fleet of construction hauling trucks and operate one of the largest pumping companies in the U.S.  Our many years in the industry and extensive experience mean we have dealt with all types of concrete mixes.

Concrete is a mixture of cement, aggregates, and water and it is important to use the right type of aggregate as it influences the concrete mix in strength, durability, workability, hardening, and ultimately the cost.  The aggregate is an inert material that accounts for 60 to 75% of the volume, 70 to 85% of the weight and originates from sand, gravel or crushed stones.   Fine aggregate is typically defined as a mix of natural sand or crushed stones with a majority of particles smaller than 3/16^th of an inch or 5mm (although some define it as less than 4.75mm).  Coarse aggregate is crushed stones or gravel particles that are larger than 3/16^th of an inch or 5mm (or as some define it as larger than 4.75mm.).  

Generally the aggregate used in concrete mixes comes from natural sand or gravel pits, rivers, seas or lake beds, hard-rock quarries, or underground mines.  The type of materials used as the aggregate effect the concrete more when it is wet than once it has cured.  When the gravel is extremely rough or irregularly shaped, it requires more water in the mix as well as more cement to give it the proper consistency. 

Aggregate is prepared by crushing, washing, and putting it through a grading process.  Grading is important as it determines the paste requirements for the concrete and regulates how much of the costly cement will be needed.  According to the Portland Cement Association, “Although some variation in aggregate properties is expected, characteristics that are considered include: grading, durability, particle shape and surface texture, abrasion and skid resistance, unit weights and voids, and absorption and surface moisture.”

Source: cement.org/cement-concrete-basics/concrete-materials/aggregate

When your project demands exceptional services and the best value, Conco can deliver.  We have been offering premium concrete services throughout the Western U.S. since 1959, and have four regional offices serving California, Washington, Oregon, Nevada and Colorado. With state-of-the-art equipment and modern facilities, we work diligently to meet goals and stay within budget.