Effect of water to binder ratio and sand to binder ratio on shrinkage and mechanical properties of High-strength Engineered Cementitious Composite

Abstract

• Total shrinkage of HSECC decreases along with the increase of W/B and S/B. • Magnitude of autogenous shrinkage approaches that of drying shrinkage along with the increase of S/B. • Summit of tensile strength and compressive strength appeared with the increase of S/B. • Ductility of HSECC is injured with the increase of S/B, especially when S/B greater than 0.6. • Decreased mortar workability and fiber distribution quality injures HSECC strength and ductility. High-strength Engineered Cementitious Composite (HSECC) usually features with low water-to-binder ratio (W/B) and low sand-to-binder ratio (S/B), for obtaining expected workability, mechanical property and multi-crack behavior. However, the low W/B and low S/B of HSECC can cause high shrinkage, which will jeopardize its volume stability and durability. In this paper, the influence of W/B and S/B on HSECC volume stability including chemical shrinkage, autogenous shrinkage and drying shrinkage, mechanical properties including compressive strength , tensile strength , tensile strain and tensile strain energy were investigated. Experiment results showed that in the W/B range of 0.13–0.24, S/B range of 0.3–0.9, the magnitude of chemical shrinkage overwhelms autogenous shrinkage and drying shrinkage; meanwhile, along with the increase of W/B and S/B, the total shrinkage is lowed and the magnitude of autogenous shrinkage tends to be comparable with drying shrinkage. In the W/B range of 0.13–0.24, along with the increase of S/B from 0.3 up to 0.8, the compressive strength and tensile strength was enhanced, however, the ductility of HSECC was lowed especially when S/B was greater than 0.6; when S/B was enhanced to 0.9, all the mechanical properties and ductility was severely injured. So, the optimum S/B of HSECC should be decided by systematically considering its influence on volume stability, mechanical strength and ductility.