Many researchers believe that the test methods used to characterize aggregates do not give producers the tools they need to correctly predict how those aggregates will impact concrete performance. The criteria producers have used to purchase their aggregates are about to dramatically change. While proper grading of the individual particles will still be important, producers will soon be reviewing other properties. The equidimensionality and angularity of coarse and fine aggregate particles and the degree and shape of the relief on their surfaces will become closely watched criteria.
The cement paste volume plays a major role in both hardened and plastic concrete and is the most expensive component of the concrete mix. Obviously, the lower the volume of cement paste in a concrete mix, the lower the cost of the total raw material content. Concretes batched with angular, rough, and irregularly shaped aggregates require a higher volume of cement paste because fewer coarse aggregate particles can be packed into a given volume compared with cubical aggregate.
The best particle size distribution for an aggregate is a result of optimizing the void content by having smaller aggregate particles fit between the larger aggregate particles. Most producers still approve their aggregate based solely on meeting broad gradation band requirements. Perhaps the producer would benefit by purchasing aggregate based on measurement of the specific surface.
