One purpose of optimum mix proportioning is to obtain a product that will perform according to certain predetermined requirements, the most essential requirements being the workability of fresh concrete and the strength of hardened concrete at a speci...
One purpose of optimum mix proportioning is to obtain a product that will perform according to certain predetermined requirements, the most essential requirements being the workability of fresh concrete and the strength of hardened concrete at a specified age. Workability is the property that determines the ease with which a concrete mixture can be placed, compacted, and finished. Durability is another important property, but it is generally assumed that under normal exposure conditions durability will be satisfactory if the concrete mixture will require special attention. Another purpose of optimum mix proportioning is to obtain a concrete mixture satisfying the performance requirements as the lowest possible cost. In this study, the properties of fresh concrete and the compressive strength of hardened concrete have been investigated, which included 16 different types of mix proportions and 3 to 5 stage reduction of unit cement content based on Cement Concrete Standard Mix Proportioning for Highway Construction. Measured properties of the fresh concretes satisfied the specified requirements. All the tested concretes showed a higher compressive strength than the specified one after the reduction of unit cement content, although there are differences in the reduced amount of unit cement content for different mix proportions. Such results indicate that the admixture and cement contents in the existing mix proportions are somewhat higher than the optimum amount conforming to the specifications. Therefore, all possible steps should be taken to reduce the cement and admixture contents of the concrete mixture within range without sacrificing the desirable properties of concrete, such as strength and durability.