An Experimental Study on the Properties of High-Performance Self-Compacting Concrete Using Polymeric Additives

Abstract

This study aims to evaluate the effect of incorporating polypropylene fibers (PF) on the fresh and hardened properties of high-performance self-compacting concrete (HP-SCC). Four concrete mixes were prepared with varying fiber volume fractions (0%, 0.2%, 0.35%, and 0.5%) relative to the total concrete volume, in order to determine the optimal dosage that balances workability and compressive strength.  Fresh properties were assessed using the Slump Flow, J-Ring, and L-Box tests in accordance with EFNARC (2005) guidelines. Compressive strength tests were conducted at curing ages of 7, 28, and 56 days following the British Standard BS 1881. The results indicated that increasing fiber content led to reduced workability and flowability, while significantly enhancing resistance to segregation and internal homogeneity. The addition of polypropylene fibers improved early-age compressive strength by up to 19% at 7 days, with the highest gain observed at 28 days (11%) for the 0.35% PF mix. At 56 days, mixes containing 0.2% and 0.5% PF maintained higher strength levels (approximately 4–5%) compared to the control mix, whereas the 0.35% PF mix exhibited a noticeable decline due to fiber distribution heterogeneity.The study concludes that a 0.2% dosage of polypropylene fibers represents an optimal choice for enhancing the performance of HP-SCC without adversely affecting workability. This dosage achieved the best balance between flowability and compressive strength and is recommended for structural applications in the Libyan context, particularly in elements prone to cracking.