Predicting the flexural behavior and experimental investigation of low carbon sea sand engineered cementitious composites (LSECCs)

Abstract

This paper presents an experimental and theoretical investigation on the flexural behavior of low-carbon sea sand engineered cementitious composites (LSECCs). Four-point bending tests and drying shrinkage tests were conducted. Combined with thermogravimetric (TG) analysis and scanning electron microscopy (SEM), the influence of water-to-binder (W/B) ratio (0.16, 0.18, 0.20, 0.25) and fly ash (FA)/ground granulated blast-furnace slag (GGBS) ratio (1, 0.5, 0) on the flexural performance of LSECCs was systematically investigated. The results indicate that all prepared LSECCs exhibited significant deflection-hardening and multiple cracking characteristics. The crack width control capacity was correlated with the ductility index; a higher ductility index led to smaller average crack widths. Decreasing the FA/GGBS ratio reduced the crack width control capacity of LSECCs, while increasing the W/B ratio had the opposite effect. Increasing the W/B ratio could increase the ductility index of LSECCs by approximately 60 %. Furthermore, reducing either the FA/GGBS ratio or the W/B ratio enhanced both first-crack strength and flexural strength of LCECCs, and contributed to mitigating drying shrinkage. Finally, based on a trilinear tensile constitutive model, both an analytical and an approximate solution for predicting the flexural performance of LSECCs were proposed. The accuracy of the proposed prediction method was validated by comparing the predicted curves with the experimental curves. This model can be used for the optimized design of the flexural performance of ECCs.