Compressive performance and analytical modeling of early strength seawater sea sand engineered cementitious composites

Early strength seawater and sea sand engineered cementitious composites (ESSECC) are novel fiber -reinforced cementitious composites that exhibit strain -hardening behavior and a high early strength. The compressive properties of ESSECC with different polyvinyl alcohol (PVA) fiber content, carbon nanotubes (CNTs) content, and water-binder ratios were investigated at different curing ages in this study. Experimental evaluations were conducted to assess compressive strength, elastic modulus, Poisson's ratio, peak strain, energy dissipation capacity, toughness index, and stress -strain curves. The experimental results showed that early strength of ESSECC reached 58.0 %, 81.6 %, and 86.7 % of its 28 -day compressive strength after 2 h, 3 days, and 7 days of curing, respectively. An increase in the PVA fiber volume fraction from 0 to 2 % resulted in a 32.8 % increase in average peak strain. Incorporating 0.15 % CNTs into ESSECC led to an average enhancement of compressive strength by 7.2 %. Based on these experimental results, an analytical model considering the effects of curing age and the addition of PVA fibers and CNTs was developed to describe the compressive stress-strain behavior of ESSECC. This model showed strong consistency with the experimental results.