Effect of basalt fiber on viscoelastic properties of hydraulic asphalt concrete

Hydraulic asphalt concrete (HAC) is susceptible to creep deformation under sustained loads, a behavior that is highly sensitive to external parameters including temperature fluctuations, stress levels, and loading duration. To evaluate and improve the viscoelastic properties and creep resistance of HAC, we investigated the reinforcement potential of 6 mm basalt fibers (BFs). The BFs were added as a reinforcement agent into the mixture across a ranging from 0% to 0.8% to determine the optimal content. The bending creep test (BCT) compared the creep behaviors of specimens with BFs incorporated as an additive at the optimal content (Group A) to those without BFs (Group B). The Burgers model was used to analyze creep compliance and viscoelastic parameters. Slope flow tests identified 0.6% as the optimal content level. At this content, the slope flow value dropped by 75.59%. This improvement stems from the adsorption and stabilization effect of the fibers. The BCT results showed that Group A demonstrated superior resistance to creep deformation. The BFs act as rigid skeleton to bridge micro-cracks. Under a high stress of 1.0683 MPa, the strain in Group A increased by approximately 1.4 times, significantly lower than the twofold increase observed in Group B. This indicated effective suppression of non-linear damage evolution. The Burgers model parameters revealed that Group A generally had superior elastic moduli (E 1 , E 2 ) and viscous coefficients (η 1 , η 2 ). The BFs bear immediate loads and enhance internal friction to resist permanent flow. This study confirms that the incorporation of BFs significantly improves the viscoelastic properties of HAC, providing a crucial reference for ensuring the durability and safety of hydraulic engineering structures.