Axial compressive behavior of basalt and polyacrylonitrile fibers reinforced lightweight aggregate concrete with industrial waste ceramsite-Lytag after freeze-thaw cycles

Lightweight aggregate concrete (LWAC) has been widely used in construction engineering due to its light weight, high natural strength, and significant durability. However, freeze-thaw cycles could accelerate the degradation of the service life of LWAC in cold regions. In this study, experimental investigation and quantitative calculation analyses were conducted to establish the axial compressive behavior of BF and PANF reinforced LWAC specimens under freeze-thaw cycles, including compressive peak stress and strain, compressive stress-strain curves, compressive modulus and compressive toughness. The results showed that although the addition of BF and PANF could enhance peak compressive stress, there was a slight improvement effect on brittleness enhancement after freeze-thaw cycles. Furthermore, the peak secant and initial tangent compressive modulus declined after the freeze-thaw cycles due to the development and spread of microcracks. The optimal content of BF and PANF on compressive modulus enhancement was established as 0.5% and 1.0%, respectively. The parameters of volume fraction, length-diameter ratio, and tensile strength were used to establish calculation equations for the peak stress and compressive modulus behaviors of fiber-reinforced LWAC. Finally, a quantitative analysis was conducted on the compressive stress-strain curves and compressive toughness calculations to provide a scientific basis for the design and application of fiber-reinforced LWAC in cold regions.