The most elementary quality control efforts one full-time technician with a slump cone, air meter, scale and thermometer assure the concrete producer and his customers that he is providing the level of quality expected. During this early stage the economics of quality control lie in saving money, primarily by avoiding as many problems as possible. A side benefit to checking air content, measuring slump and making cylinders: the producer begins to see where he can make improvements in both the manufacture and the product. Part of profitability can be directly related to efficiency of production and to efficiency, or optimization, of mix designs.
To some people optimization means reducing cement content and that might very well be what is needed. The object of optimizing a design is to produce the best possible concrete for the least amount of money. The concern of many users is that the producer may "over optimize," leaving no room for normal variations in materials or job conditions. This would soon prove to be counterproductive and nonprofitable. The partner of optimization is consistency. Without consistency in materials and production, optimizing should not even be considered. Hence, the next stage of quality control becomes testing of the concrete making materials. Gradations of aggregates must be determined, cement must be tested, laboratory mixes must be made and evaluated, and cylinders must be cast and broken.
Regardless of how hard the ready mixed concrete producer tries, not all the problems go away. The only satisfaction is that fewer are caused by ignorance and that when problems do occur, his personnel are better able to deal with them technically. The cost of removing concrete from the fiftieth floor of a high-rise can be tens or even hundreds of thousands of dollars. In such cases the concrete supplier cannot afford to merely accept the findings of an engineer or independent laboratory. The expertise of his technical staff together with the records he has kept on the consistency and performance of his materials must provide the ability to determine the extent of his involvement, if any.