The Effect of Kevlar Fibers on the Mechanical Properties of Lightweight Perlite Concrete

Abstract

Fiber-reinforced concrete contains a fibrous material that increases its structural cohesion. The use of separate short fibers distributed in a random direction improves the strength of Lightweight Concrete (LWC) without exceeding its upper-density limit, improving its high fragility and mechanical properties compared to Natural-Weight Concrete (NWC). This study investigated the effect of adding Kevlar 49 fibers with three percentages of cement weight, 0.5, 1, and 1.5%, on the workability, dry density, and tensile and compressive strength of LWC. The use of Kevlar fibers in different proportions improves mechanical properties, significantly increases durability, and reduces the workability of LWC. The increase in compressive strength when adding 0.5% fibers was 19 and 15% and when adding 1% was 10 and 6%, after 7 and 28 days, respectively. At 1.5%, after 7 and 28 days, there was a decrease in compressive strength due to fiber agglomeration. Additionally, increasing the fiber dose from the optimal value caused a sharp decrease in workability by 37-40%.