Comparison of the effect of basalt and glass fibers on the fracture energy of asphalt mixes using semi-circular bending test

Abstract

This paper has focused on the effect of basalt and glass fibers in HMA in terms of crack formation and damage mechanisms. The experimental study was carried out under two stages; i) defining optimum fiber lengths and rates based on Marshall Stability performances using three different fiber lengths (4 mm, 12.5 mm, 22.5 mm) and three different fiber rates (0.75%, 1.00% and 1.5% by weight), ii) examining of fracture tests by using the optimum fiber values (4 mm fiber length and 0.50%, 0.75%, 1.00% fiber content by weight) obtained from the first stage. Fracture energy characteristics of HMA mixtures were examined via Semi-Circular Bending (SCB) test. A total of 24 SCB test specimens from 6 different series, B-0.50, B-0.75, B-1.00, G-0.50, G-0.75, and G-1.00, were used in the experiments. Experimental results were discussed based on some basic physical properties, fracture energy (Gf), dissipated energy (DE), flexibility index (FI), and crack resistance index (CRI) values of HMA mixtures. When 0.50% basalt fiber is utilized in asphalt mixtures, the maximum peak load and Gf value are achieved. Moreover, using 1.00% basalt and 0.75% glass fiber in asphalt mixtures yielded the highest values of FI and CRI, respectively. Nevertheless, when 1.00% glass and 0.75% basalt fiber were added to asphalt mixtures, the minimum values of FI and CRI were obtained, respectively.