High-strength high-ductility seawater sea-sand Engineered Cementitious Composites: Mechanical properties, cracking behavior and micro-mechanics

This study developed strain-hardening seawater sea-sand engineered cementitious composites (SS-ECC) with both high-strength and ultra-high tensile ductility for the first time using CaCO 3 whiskers (CW). The developed SS-ECC exhibited a compressive strength of 132.7 MPa and successfully pushed the ultimate tensile strain capacity over 10 %. Investigations into crack characteristics and micro-mechanics were conducted to analyze in depth the obtained tensile performance. The results showed that the incorporation of 0.3 vol% CW increased the degree of crack saturation and decreased the crack width, leading to a further increase in the ultimate tensile strain capacity. With CW dosage increasing from 0.3 vol% to 0.8 vol%, the compressive strength increased significantly, but the ultimate tensile ductility decreased. In addition, this study took into account the effects of CW and PE fibers in the micro-mechanical model and theoretically explained the synergistic effect of CW and PE fibers on the enhancement of tensile performance of SS-ECC through the obtained PSH indices. The finding provides new insights into the production of high-cost efficiency and high overall performance index ( f c f t epsilon / w ) for ultra-high ductility SS-ECC, with promising applications in sustainable marine infrastructures.