The 4th Asian Concrete Federation Symposium on Emerging Technologies for Structural Longevity (ACF2023- ETSL)

Ultra-high-performance concrete (UHPC) is a promising cementitious composite to produce lightweight and high performance structures. Steel fibres are an essential constituting material of UHPC to prevent the brittle behaviour of UHPC at failure, but the high cost of incorporated steel fibres impedes the wider applications of UHPC to some extent. This paper proposes a concept to produce UHPC reinforced with macro fibres processed from waste GFRP, therefore addressing two issues of the high cost of UHPC as well as the difficulty in disposal of waste GFRP simultaneously. A series of tests have been carried out to investigate the effect of adding macro fibres on the properties of UHPC. The test results show that the incorporation of macro fibres leads to a loss of the workability and a reduction of up to 21.8% in the compressive strength, but improves the its flexural strength and flexural toughness greatly by up to 27.9% and 46.9 times, respectively. The tensile constituting relationship has been converted from the results of the bending tests through their inverse analysis. The proposed concept of producing UHPC with recycled macro fibres and UHPC contributes to lowering the price of UHPC, whose properties are comparable to that of UHPC with steel fibres, and finding an effective routine to valorize the waste GFRP.