Influence of sodium hydroxide (NaOH) molarity on fresh properties of self-compacting slag-based geopolymer concrete containing recycled aggregate

The present study is an attempt to examine the feasibility of developing a sustainable self-compacting concrete (SCC) made with geoploymer binder and recycled aggregate. The study explores the effects of four sodium hydroxide (SH) molarities (8 M, 10 M, 12 M and 14 M) on the fresh properties of self-compacting slag-based geopolymer concrete. Eight slag-based geopolymer concrete mixtures were examined. These mixes are divided into two groups: GPN group in which the mixtures are made with natural aggregate (NA) and GPR group in which the mixtures are made with recycled aggregate (RA). Each group includes four mixes made with the four mentioned SH molarities. The mixtures were examined for its flowability, passing ability, viscosity and segregation resistance and the results were tested against the EFNARC recommendations for SCC. It was concluded that recycled aggregate and the molarity of sodium hydroxide affects the fresh properties of SCC. But, developing self-compacting slag-based geopolymer concrete that meets the limits of EFNARC is feasible.