The effect of sand to cement proportion and size of sands on mechanical properties of reactive powder concrete (RPC)

In this study, the effect of sand to cement ratio and size of sands on compressive strength of reactive powder concrete was examined. Reactive powder concrete (RPC) has homogeneous microstructure, low porosity, and high durability. Mechanical properties of RPCs can be modified by changing ratio of sand to cement and the size of fine aggregates. This study contains two phases based on changing the size of sands. The size of sands in the first phase is 0.15-0.6 mm (passing sieve No. 30 and remaining on sieve No. 100) and in the second one is smaller than 0.6mm. In all of mix designs weight of sand and cement is 2Kg. Also the proportion of sand weight to cement weight varies from 1.75 to 2.6. The amount of plasticizer applied in two phases is 2% of cement weight.After curing of specimens, they tested for compressive strength of concrete in specific days. It is observed that workability of mixture decreased in high proportions of sand to cement and mixtures needed more water. In general, the usage of sands grain below the size of 0.15mm has no substantial effect on compressive strength of the samples. Furthermore, in terms of expenses, replacing cement with sand in high S/C ratios has economic benefits which slightly increase compressive strength.

Keywords:

RPC , Compressive strength , Microstructures , Size effect , Sand to cement ratio