Optimisation of rheological parameters and mechanical properties of Engineered Cementitious Composites (ECC) using regression-based models

Engineered Cementitious Composites (ECC) have superior mechanical and durability performance than conventional concrete. One of the major challenges of producing ECC is to ensure appropriate rheology for uniform fibre distribution, which is the prerequisite of its strain-hardening robustness. In this study, the combined and interactive effects of polycarboxylate-based superplasticisers (SP) and viscosity modifying admixtures (VMA) on the rheological behaviour of ECC were systematically investigated. The evolution trends of yield stress and plastic viscosity were characterised in detail with a rheometer. The most desirable range of rheological condition for uniform fibre distribution was identified and the optimal SP-VMA combinations were predicted by regression modelling. Results showed that ECC produced with the optimised dosages of SP and VMA exhibited 200% enhancement in deflection under four-point bending. This study provides effective guidance on rheology control and optimisation of ECC materials and could further benefit for more extensive ECC development and applications.