Effect of the heat curing on strength development of ultra-high performance fiber reinforced concrete (UHPFRC) containing dune sand and ground brick waste

This work aims to investigate the strength development of ultra-high performance fiber reinforced concrete (UHPFRC) containing ground dune sand (GDS) and ground brick waste (GWB) as a substitutions of cement and dune sand (DS) as an aggregate. The variables are the nature of addition (GDS and GWB) in the binder and the heat curing at different temperatures (20°C and 60°C) at 7 days of curing. Two temperatures 20°C and 60 °C were applied to samples with intermediate levels for 8 hours in total. In this study, two types of cements (CEMI and CEMII) were used to prepare UHPFRC. The GWB was replaced by GDS at levels of 10, 20 and 30% by weight. The results show that the obtained concretes develop a high mechanical performance with a suitable heat treatment according to the cement type and the used fiber. The compressive strength at 7 days of UHPFRC has increased with heat curing (at 60 °C) compared to that obtained at 28 days and measured at 20 °C. Results show also that values of compressive strength of concrete containing DS are close to those obtained by the control concrete. This study has showed that the dune sand can be used in UHPRC, and that the substitution of the GWB by GDS can provide concretes with acceptable mechanical performance