Ensuring the use of effective quality control measures in concrete projects prevents the addition of concrete to the project that fails to meet the regular standards attributed to quality concrete. In residential construction, several standards are used to define the expected quality of concrete. These quality standards are defined by the American Concrete Institute and the Concrete Foundation Association. Implementing quality control practices to ensure that concrete meets and exceeds the standards set by these organizations guarantees that concrete used has the strength to withstand the demands of the project.

Water and Concrete

Maintaining the proper ratio of water to the concrete mixture is the most vital issue of quality control for concrete. The ratio is commonly tested by measuring the slump of the concrete mixture. Concrete testing uses a cylindrical cone approved for testing water-cement ratios and a fresh batch of concrete. The cone is filled with concrete and then the cone is removed. The resulting sag that occurs is measured to determine the slump of the mixture, according to Joe Nasvic of Residential Concrete Magazine. In residential construction, the ideal slump measure is within 4 to 5 inches. Mixtures with slump indicating an excess of water in the mixture produces concrete that has less strength, increased shrinkage and less durability than properly mixed concrete.

Requirements for Residential Concrete Construction

In addition to preventing weakening of concrete by adding too much water to the mix, adherence to the standards of ACI 332-04, The Requirements for Residential Concrete Construction, is equally important. The ACI 332-04 provides recommendations and charts designed to ensure that concrete, when properly mixed and applied, will support the intended construction load. The recommendations take into account various environmental factors, such as weather and soil conditions at the building site, along with the intended load the concrete must support.

Timing and Curing

Even when the proper water mixture is utilized and the concrete is installed according to ACI standards, quality control requires knowledgeable concrete professionals that are aware of the necessary timing for concrete finishing to avoid trapping water below the surface. Improper finishing techniques that trap water below the surface lead to potential weakening of the system. As timing is affected by the conditions of individual job sites, such as humidity and temperature, professional concrete finishers are the best able to determine the proper timing for finishing and the time frame necessary for the full curing of the product after installation. Concrete subjected to a load prior to reaching a satisfactory level of curing can be compromised.