Fiber Treatment for Improving Foam Concrete Flexural Behavior

Abstract

Foam concrete is widely used in situations where toughness is crucial. Adding polyvinyl alcohol (PVA) fibers is a common way to make foam concrete stronger and tougher. However, these fibers show extremely high bond strength with the matrix, causing them to break prematurely when the foam concrete cracks, which reduces their effectiveness. This study introduces a novel water-based water-repellent treatment for PVA fibers in foam concrete with a density of 800 kg/m3. Test results show that treated fibers had a weaker bond with the concrete, pulled out longer during bending tests, and distributed better. Although treated fibers slightly decreased the foam concrete’s compressive strength (by up to 13%) compared to untreated fibers, they significantly increased flexural strength and toughness and made the cracks narrower. Treated fibers improve toughness by 20.8% at a displacement of 0.8 mm compared to untreated fibers. This toughness enhancement would likely be even greater at longer displacements.