Experimental study and mechanism analysis on the basic mechanical properties of hydraulic basalt fiber asphalt concrete

In order to explore the effect of basalt fiber on the basic mechanical properties of hydraulic asphalt concrete, uniaxial compressive and uniaxial tensile tests were carried out by considering 3 fiber lengths and 4 fiber contents. The following conclusions were drawn from the experimental results: With the increase of fiber length, the number of cracks in the compressive failure mode of hydraulic asphalt concrete was gradually decreased. With the increase of fiber content, the number of cracks in the compressive failure mode of hydraulic asphalt concrete was gradually increased. Both the basalt fiber content and fiber length had little effect on the tensile failure mode. With the increase of fiber length, the compressive strength and compressive modulus of hydraulic asphalt concrete tended to decrease first and then increase, while the tensile strength did not change much. With the increase of fiber content, the compressive strength, tensile strength and compressive modulus all tended to increase first and then decrease. The increase of fiber length had little effect on the deformability of hydraulic asphalt concrete, while the increase of fiber content had a recognizable effect on the deformability. Based on the results above, the optimal fiber length and fiber content were 3 mm and 3‰, respectively. Under this working condition, the compressive and tensile strengths were increased by 31% and 42%, respectively, compared with the sample without fiber. Then, the mechanical properties of hydraulic basalt fiber asphalt concrete were examined by the nano-indentation technology to obtain the elastic modulus of the transition interfaces and each constituent phase. Moreover, the scanning electron microscope and X-ray computed tomography (X-ray CT) scanning technologies were applied to reveal the action mechanism of basalt fiber in the hydraulic asphalt concrete. The achievements of this study provide a theoretical basis for the research and application of basalt fiber in the hydraulic asphalt concrete.