Mechanical properties of hybrid fiber reinforced coral aggregate seawater concrete based on scanning electron microscopy (SEM)

Based on the cubic compressive strength and flexural strength tests of 18 sets of hybrid fiber reinforced coral aggregate seawater concrete (HFRCASC) and 1 set of C40 grade benchmark CASC, the effects of different mixing methods of polypropylene fibers (PPF), basalt fibers (BF), and glass fibers (GF), as well as the mixing amounts, on the mechanical properties of HFRCASC were investigated. The results show that the cubic compressive strength and flexural strength of HFRCASC are higher than that of C40 benchmark CASC, and the maximum improvement of cubic compressive strength reaches 28.7 % and flexural strength increases by 26 % when the mixing amount of PPF and BF is 2 kg/m³. PPF is a significant factor affecting the compressive strength of HFRCASC, and with the increase of PPF dosage flexural strength showed a trend of increasing first and then decreasing, GF is not obvious to improve the compressive strength. Diversified regression analysis of the test results using SPSS resulted in a predictive model for the compressive strength of HFRCASC cubes with high model accuracy.