Experimental and 3D mesoscopic investigation of uniaxial compression performance on basic magnesium sulfate cement-coral aggregate concrete (BMSC-CAC)

The constitutive relationship of basic magnesium sulfate cement-coral aggregate concrete (BMSC-CAC) under uniaxial compression was investigated using cylindrical specimens. The equal strain monotonic loading method was applied to obtain the stress-strain curves. Mechanical parameters such as elastic modulus (E-c) and Poisson's ratio(mu) were calculated. A 3D random aggregate mesoscopic model was used to simulate the failure process and crack propagation. The results show that when the strain approximated to maximum value, BMSC-CAC was rapidly destroyed in the shape of splitting. Compared with ordinary cement, the brittleness of concrete can be effectively improved due to the high toughness of basic magnesium sulfate cement (BMSC). The segmented constitutive equation of BMSC-CAC was given, which could express all of the compression test characteristics. The relative error of the peak stress and strain between the experiments and simulations were small. Analysis of the failure process reveals that damage first appears in the mortar and ITZ of the concrete, with micro-cracks converging into huge oblique cracks through the aggregate.