Investigation of fresh, shrinkage, and mechanical properties in iron sand high-strength engineered cementitious composites: Effects of water-to-binder ratio and fiber volume fraction

Abstract

High-strength engineered cementitious composites (HS-ECC) provide remarkable advantages in the construction industry by reducing specimen size and improving material utilization, leveraging the benefits of engineered cementitious composites (ECC) and ultra-high-performance concrete (UHPC). However, challenges such as material scarcity, low elastic modulus, and high shrinkage limit the widespread application of HS-ECC. This research addresses these issues by developing HS-ECC through substituting quartz sand with iron sand under different water-to-binder (w/b) ratios to achieve high elastic modulus, low shrinkage, and varying compressive strength levels. Ten HS-ECC mixtures were produced with various w/b ratios, aggregate types, and fiber volume fractions to assess their impacts on fresh, shrinkage, and mechanical properties. The experimental results demonstrated that substituting quartz sand with iron sand decreased shrinkage. Specifically, iron sand HS-ECC showed a decrease in autogenous and drying shrinkage by 22.5 % and 23.6 %, respectively, compared to quartz sand HS-ECC at 0.14 w/b ratio. Additionally, as the w/b ratio increased from 0.14 to 0.20, autogenous and total shrinkage decreased by more than 14.0 %, while drying shrinkage increased by more than 74.7 %. For workability tests, slump flow and consistency increased with higher w/b ratios, albeit with a concurrent reduction in mechanical strength. Notably, the elastic modulus increased by 6.8 % at 0.16 w/b ratio with iron sand substitution. This study lays the groundwork for the developing HS-ECC with higher elastic modulus and lower shrinkage, contributing to advancement of this promising material in civil engineering applications.