Impact of polypropylene fibers on the rheological, mechanical, and thermal properties of self-compacting concrete

The objective of this experimental investigation is to examine the impact of using polypropylene fibers on the properties of self-compacting concrete (SCC). Five mixtures were prepared, one reference concrete (without fibers) and four other SCC containing, 0.05, 0.1, 0.15, and 0.2% of polypropylenes fibers. Rheological (slump flow, yield stress, and plastic viscosity) and mechanical (compressive strength) properties as well as the thermal conductivity and porosity were evaluated. The results indicate that increasing fibers percentage affect negatively the workability and compressive strength of concrete. For example, addition of 0.2% of polypropylene fibers fell the mixes outside the range of self-compacting concretes and reduced their compressive strength by 20% compared to reference concrete. For the same percentage of fibers (0.2%), results revealed an increase of 23% of the total porosity in comparison with reference concrete. Interestingly, increasing polypropylene fibers’ percentage decreased remarkably the thermal conductivity of concrete; enhancing thus its thermal performance.