Enhancing foam concrete: A comparative analysis of PLA+ fiber reinforcements with plain, hooked, and corrugated fibers

Abstract

This study examined the enhancement of foam concrete by using hooked, plain, and corrugated PLA+ fibers that were made with a 3D printer. The PLA+ fibers were added into the foam concrete mixtures at volumetric ratios of 0.5 %, 1 %, and 1.5 %. The main objective was to evaluate the mechanical and durability characteristics of the composites, such as compressive and flexural strengths, thermal conductivity, water absorption, and freeze-thaw resistance. In addition, the microstructural interactions between the fibers and the concrete matrix were examined using scanning electron microscopy (SEM). The inclusion of hooked fibers greatly improved the flexural strength, resulting in a notable 48.57 % improvement when the fiber usage rate was set at 1 %. Although the samples with stronger fiber reinforcement showed higher water absorption, all recorded values were below the acceptable threshold of 30 % for practical engineering purposes. In addition, the thermal conductivity of the samples dropped when PLA+ fibers were included, reaching its minimum value at a concentration of 1.5 %. After subjecting the samples to 15 and 30 freeze-thaw cycles, it was observed that all samples reinforced with fiber showed good frost resistance, with a mass loss of less than 5 %. The SEM analysis revealed that the fiber-reinforced samples exhibited a denser microstructure compared to the reference mix, resulting in enhanced pore structures. And the thermal conductivity of the samples declined as the amount of PLA+ fiber increased. The fiber-reinforced materials exhibited good frost resistance, determined by a mass reduction of less than 5 % after 15 and 30 freeze-thaw cycles.