Effects of fiber characteristics and specimen sizes on static and dynamic split-tensile failures of BFLAC: 3D mesoscopic simulations

Abstract

In this study, a three-dimensional mesoscopic numerical model considering concrete heterogeneity and explicit modelling of basalt fibers was established to simulate the static and dynamic split-tensile failures of basalt fiber-reinforced lightweight aggregate concrete (BFLAC), with a special focus on the influences of structure sizes (D = 100, 200, 300 and 400 mm), basalt fiber contents (Vf = 0.1 %, 0.2 % and 0.3 %), fiber lengths (Lf = 6, 12, 18, 24 mm) and loading strain rates (ε̇ = 10-5/s ∼ 100/s) on split-tensile failure patterns, deformation characteristic and failure strengths. Simulation results indicate that as the fiber length increases, split-tensile strength of BFLAC enhances first and then remains unchanged. As the fiber content increases, both static and dynamic split-tensile strengths enhance, showing a fiber reinforcement effect which increases with the rising strain rate rise and reaches a threshold when the strain rate exceeds 1/s. Under static and low strain rates, the size effect on split-tensile strength of BFLAC is reduced by the addition of basalt fiber content; while there is a reverse size effect under high strain rates and it is strengthened with the increasing fiber content. Besides, the strain rate effect of BFLAC is stronger with the increasing basalt fiber content. A unified TDIF formula of BFLAC considering the influence of basalt fiber content was proposed, which can provide a valuable reference for the dynamic performance simulations and calculations.