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

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. (C) 2019 Published by Elsevier Ltd.