Mechanical properties of concrete-reinforced fibres and powders with crushed thermoset composites: The influence of fibre/matrix interaction

This paper focuses firstly on the formulation and mechanical behaviour of concrete reinforced fibre and powder (CRFP). Secondly, we present the effect of silane treatment on the bond characteristics of the fibre–matrix of ultra-high-performance concrete (UHPC). The initial objective of the study was to optimize the incorporation of fibres and powders in high performance concrete (HPC). Two materials were investigated. The first involved replacing a volume of sand by an equivalent volume of fibres and powders. The second type was obtained by replacing an equivalent volume of silica fume with powders. Testing of the first material showed that the incorporation of fibres and powders by sand substitution increased the bending and tensile strength by 32%. In the second material, the substitution of silica fume by the powder led to an increase of 37% in flexural and tensile strengths.The second section of this paper focuses on silane-treated fibres. The experimental results on fibre pullout tests under different conditions are reported. Various silane treatment contents ranging from 0% to 1% were studied. Fibre pullout tests were conducted to measure the bond characteristics of fibres in the UHPC matrix. The treatment by vinyl trimethoxy silane (VTMO) can effectively enhance the fibre–matrix interfacial properties, especially the fibre pullout energy. It was concluded that in terms of the bond characteristics, the optimal silane content is 0.5% under these conditions.

▸ Concrete reinforced fibre and powder is developed. ▸ Fibre–cementitious matrix bond characteristics improved by using silane treatment. ▸ Incorporation of fibres/powders increases the bending and tensile strength. ▸ Mechanical properties were increased by using fibres/powders in cement matrix.