Feasibility of using high-volume pozzolanic fillers to develop sustainable engineered cementitious composites (ECC)

To decrease the environmental load caused by the cement production, high volume of supplementary cementitious materials (SCMs) are adopted to prepare the engineered cementitious composites (ECC). This work prepares an eco-friendly ECC mixed with high-volume SCM (HSECC) by incorporating silica fume, fly ash and diatomite powder (DP) to reduce the cement dosage. The mechanical properties, volume deformation, microstructure, and environmental benefit of HSECC are investigated. Experimental results present that with increasing the DP replacement ratio, the compressive strength of the HSECC gradually reduces, whereas its autogenous shrinkage deformation increases. Furthermore, with increasing the DP content, tensile strain capacity and crack number of HSECC increase, but the tensile strength reduces. The tensile strain capacity of HSECC containing 20% DP increases by 67.8% compared with the HSECC without DP. Utilizing DP to replace the cement reduces the amount of hydration production, but it optimizes the pore structure of sample because of the filling effect, pozzolanic reaction and internal curing effect of DP. Moreover, the HSECC containing DP has a lower carbon emission and cost compared to the HSECC without DP. This study gives a new strategy and theoretical support for producing the eco-friendly high-ductility ECC.