Experimental study on dynamic compressive properties of early strength seawater and sea-sand ECC

Early strength seawater and sea sand engineered cementitious composites (ESSECC) are a new type of material with high early strength and strain-hardening behavior. In this study, the dynamic compressive tests of ESSECC were conducted employing the Split Hopkinson pressure bar (SHPB), with various strain rates and dosages of PVA fiber and CNTs considered. The failure patterns, dynamic stress-strain curves, dynamic peak stress, dynamic peak strain, dynamic increaser factor (DIF), and energy absorption capacity were systematically analyzed. Results indicated that the dynamic compressive behavior of ESSECC, including dynamic peak stress, dynamic peak strain, DIF and energy absorption capacity exhibited significant strain rate effect , with all parameters increased with the rising of strain rate . The incorporation of PVA fiber enhanced the crack propagation resistance, while CNTs filled nano pores in the matrix, resulting in a denser microstructure. The hybrid fibers at multiple scales exhibited a synergistic effect , effectively improving the dynamic compressive performance of ESSECC. Furthermore, the dynamic enhancement mechanism of ESSECC was analyzed by scanning electron microscope (SEM) images. • The dynamic behavior of PVA fiber and CNTs reinforced ESSECC has been investigated under different strain rates. • A new model has been proposed for the DIF of ESSECC. • The 3-day dynamic compressive strength of ESSECC reaches 85.3 % of 28-day strength. • The synergistic effect of PVA fiber and CNTs improves the dynamic behavior.