Fracture properties of graded basalt fiber reinforced concrete: Experimental study and Mori-Tanaka method application

Abstract

Fiber additions can improve the flexural strength of concrete, which is brittle. In this study, the improvement effect of graded basalt fibers on the mechanical properties of a matrix was studied at the macroscale using the elastic modulus, and compressive and flexural strengths. At the mesoscale, fiber concrete is regarded as a multiphase composite material composed of aggregate, cement mortar, fiber, and aggregate-mortar and fiber-mortar interface transition zones (ITZ). The Mori-Tanaka (M−T) homogenization theory was used to calculate the elastic modulus of basalt fiber-reinforced concrete (BFRC), and the accuracy of the test parameters was verified by comparing the test results with the homogenization results. Moreover, a finite element model (FEM) was established to reveal the crack evolution process and crack resistance mechanism of the graded fibers. The FEM results revealed that the addition of fibers reduces the stress intensity factor at the crack tip and inhibits the generation and development of cracks. Moreover, because of the side wall effect, short fibers were evenly distributed in the mortar and long fibers, which absorb and consume more energy during crack development and improve the mechanical strength and deformation capacity of the concrete, were more distributed near the aggregate.