Experimental Study on Basalt Fiber Crack Resistance of Asphalt Concrete Based on Acoustic Emission

Experimental Research on the Anti-Reflection Crack Performance of Basalt Fiber Modified Rubber Asphalt Stress-Absorbing Layer

Reflection cracks are one of the most common problems in semi-rigid base pavement. Setting a stress absorption layer can effectively delay the occurrence of reflection cracks, but further improvement is still needed in its interlayer bonding performance and anti-reflection crack performance. Considering the excellent crack resistance of basalt fibers and the good elastic recovery ability of rubber asphalt, it is considered worthwhile to incorporate them into traditional stress absorption layers to improve performance. To simulate the actual pavement layer effect, composite specimens consisting of a cement-stabilized macadam base + basalt fiber rubber asphalt stress-absorbing layer + AC-20 asphalt mixture surface layer were prepared to evaluate their performance through interlayer direct shear tests, interlayer tensile tests, three-point bending tests, and overlay tests (OTs). To determine the optimal fiber blending combination, four fiber lengths (3 cm, 6 cm, 9 cm, 12 cm) and four fiber proportions (120 g/m2, 140 g/m2, 160 g/m2, 180 g/m2) were selected respectively. The specific effects of basalt fibers with different lengths and dosages were analyzed. The results show that compared with the absence of fibers, the improvement of interlayer bonding performance of rubber asphalt with basalt fibers is not significant, and it has certain limitations; however, the improvement of anti-reflective crack performance is significant, with an increase of up to 305.5%. This indicates that the network structure formed by basalt fibers and rubber asphalt stress absorption layer can effectively absorb and disperse external loads, causing an excellent crack resistance effect. Meanwhile, the results indicate that the main factor affecting its interlayer bonding strength and anti-reflective crack performance is the fiber content. Based on the comprehensive analysis of the performance and economy of the stress absorption layer of basalt fiber rubber asphalt, the optimal fiber parameter combination recommended is as fiber length 9 cm and fiber content 160 g/m2. These results can provide a reference for the design and performance evaluation of basalt fiber rubber asphalt stress absorption layer, and have certain application value.

Recent Advances in Basalt Fiber Reinforced Asphalt Mixture for Pavement Applications

This paper conducts a thorough review of the literature on the feasibility and current state-of-the-art incorporation of basalt fiber (BF) into asphalt pavement materials, focusing on fiber characteristics, dosage, incorporation methods, mixture properties, and surface modification techniques. The optimum basalt fiber dosage should be determined based on engineering performance parameters such as asphalt type, fatigue cracking, thermal cracking, rutting, and moisture resistance of asphalt mixtures. Basalt fibers are added to asphalt mixes by dry method or mixed method to achieve better dispersion. Adding BF to asphalt mixtures increased performance characteristics like cracking resistance, rutting resistance, and fatigue resistance. Overall, incorporating BF into asphalt mixtures would lower costs while increasing pavement service life. More research is needed to fully understand the effects of different sizes of BF on pavement performance and the possible environmental and economic repercussions of fiber surface alteration.

Numerical Simulation on Seismic Behavior of Steel Fiber Reinforced Concrete Beam-Column Joints

Steel fiber reinforced concrete (SFRC) is a novel material of concrete, which has a great potential to be used in practical engineering. Based on the finite element software Opensees, the main objective of this paper presented a numerical simulation method on investigating the seismic behavior of SFRC–beam-column joints (BCJs) through modifying the calculation method of joint shear and longitudinal reinforcement slip deformations. The feasibility and accuracy of the numerical modeling method were verified by comparing the computed results with experimental data in terms of the hysteresis curves, skeleton curves, feature points, energy dissipation, and stiffness degradation. And then, the influences of some key parameters on the seismic behavior of BCJs were investigated and discussed in detail. The parametric studies clearly illustrated that both adding the steel fiber and increasing the stirrup amount of joint core area could significantly improve the seismic behavior of BCJs. The axial compression ratio had limited influence on the seismic behavior of BCJs. Finally, based on the main factors (steel fiber volume ratio, stirrup amount, and axial compression ratio), a formula for predicting ultimate shear capacity is derived.