Analysis of microstructure and compressive properties of full coral concrete under fiber reinforcement

Abstract

Based on the compressive tests of 120 cubes in 10 groups, the effects of different chopped fibers (polypropylene fiber PPF, glass fiber GF, basalt fiber BF) and their content on the compressive properties of coral aggregate seawater concrete (CASC) were studied. The microstructure of CASC was analyzed by scanning electron microscopy (SEM), and the relationship between microstructure and macroscopic properties was established. The results show that the growth rate of compressive strength of fiber CASC is fast in the early stage and slow in the late stage. When 1 kg/m3, 2 kg/m3 and 3 kg/m3 of PPF were added to the CASC, the compressive strength increased by 6.2 %, 17.4 % and 9.9 %, respectively. SEM images show that PPF forms a dense, chaotic three-dimensional mesh structure in the matrix, which can effectively inhibit crack extension within a certain doping range. Compared with BF and GF, PPF has a more significant effect on improving the mechanical properties of CASC, and the optimal PPF content is 2 kg/m3. Adding PPF could improve the brittleness of concrete and make it show good ductility when it is destroyed.