Mechanical properties tests and multiscale numerical simulations for basalt fiber reinforced concrete

Basalt fiber reinforced concrete (BFRC) can be regarded as a composite of cement mortar, aggregate and basalt fiber. In this paper, the influences of the basalt fiber’s length and content on the fundamental mechanical properties of concrete were investigated by multi-scale simulation. At the mesoscopic scale, a damage constitutive model was developed in accordance with the Mori-Tanaka homogenization theory and progressive damage theory to predict the composited material properties of BFRC. At the macroscopic scale, the obtained material properties of BFRC from mesoscopic were input into the finite element specimen model to simulate the mechanical performance of BFRC. By coupling the mesoscopic material model with the finite element macroscopic model, the effects of basalt fiber on the mechanical performance of BFRC specimen at macroscopic scale can be investigated. The compressive, splitting tensile, and bending performances of BFRC were studied by both experiments and numerical simulation. The predicted results from the proposed multiscale model show a good agreement with the experimental results. It is also found that with the increase of fiber content, the compressive and splitting tensile strengths of concrete increase first followed by decrease while the bending strength keeps increase. For the different lengths of basalt fiber, the BFRCs with 6 mm basalt fiber display a better compressive and splitting tensile performance than BFRCs with 12 mm fiber, whereas the differences in bending strength is slight. Results shows that BFRCs with 2‰ 6 mm basalt fiber can achieve the maximum strength. Moreover, the size effect on BFRC’s basic properties of BFRC with 2‰ 6 mm basalt fiber was further explored by regression. Those regression formula has very high R2 values.