Optimum mix design of concrete made with dune sand as fine aggregate

The use of dune sand for replacing ordinary fine aggregate in concrete has environmental benefits and the feasibility has been demonstrated in China and some Middle East countries. However, the use of dune sand tends to decrease the engineering properties (compressive strength and workability) of concrete. To improve engineering properties of dune sand concrete (DSC), the current paper is to check which strength and slump levels can be obtained by optimization of mix proportions. Results show that the ratio of cement to sand (C/S) has significant influence on the engineering properties of DSC. At low C/S ratio, the engineering properties of DSC are inferior to those of concretes made with normal sand (NSC). However, when C/S ratio exceeds 0.75, DSC has comparable or even better engineering properties compared to NSC. In the range of investigated C/S ratio, DSC has comparable tensile splitting strength and elastic modulus to its reference NSC. Based on the experimental results, the Australia dune sand can be used as fine aggregate whenever mix proportions are properly controlled.