An Experimental Investigation of the Mechanical Properties of Lightweight Concrete with Pumice Aggregate and Polypropylene Fibers

This study investigates how adding Polypropylene Fibers (PPF) affects the mechanical properties of structural lightweight concrete. Four mixes with varying fiber contents 0%, 0.5%, 1%, and 1.5% were tested at different curing ages up to 90 days. The results show that PPF significantly improves the Flexural Strength (FS) and Tensile Strength (TS), with a moderate increase in Compressive Strength (CS). The mix containing 1.5% PPF achieved the highest TS, likely due to enhanced microcrack bridging and a denser microstructure. The statistical analysis confirmed that the fiber content strongly influences the strength development, particularly the tensile performance. Overall, incorporating 1%-1.5% PPF appears to be an effective way to enhance the durability, toughness, and structural integrity of lightweight concrete, making it suitable for demanding construction applications.