Use of Polymeric Fibers in the Development of Semilightweight Self-Consolidating Concrete Containing Expanded Slate

Abstract

This paper aims to evaluate and optimize a number of semilightweight self-consolidating concrete (SLWSCC) mixtures containing coarse and fine aggregates, lightweight expanded slate, and reinforced with different types of polymeric fiber. The fibers used were 8 and 12 mm polyvinyl alcohol (PVA8 and PVA12), and 19 mm polypropylene (PP19). The developed mixtures included different binder contents (550 and 600 kg/m3), fiber volumes (0.3% and 0.5%), and coarse-to-fine (C/F) aggregate ratios (0.7 and 1.0). Two normal-weight self-consolidating concrete (NWSCC) mixtures made with fine and coarse crushed granite aggregates also were tested in this investigation for comparison. Although the use of polymeric fibers negatively affected the fresh properties of the mixture, it was possible to develop successful SLWSCC mixtures with significantly improved flexural strength using up to 0.5% fibers. SLWSCC mixtures with shorter fibers (PVA8) had better fresh properties and strengths compared to mixtures with longer fibers (PVA12 and PP19). A minimum of 550 kg/m3 binder content was required to develop SLWSCC mixtures with acceptable self-compactability. However, using 600 kg/m3 binder content contributed to improving the fresh properties of the mixture, which allowed using a higher content of lightweight expanded slate aggregate, achieving a further reduction of the mixture density. The results also showed that unlike the lightweight coarse aggregates, the use of lightweight fine aggregates helped to develop mixtures with higher flowability, passing ability, and strengths.