Development of eco-friendly geopolymers with ground mixed recycled aggregates and slag

The recycling of masonry demolition waste has attracted growing attention in recent years. In this paper, the feasibility of developing eco-friendly geopolymers using ground mixed recycled aggregates (GMRA) was investigated. Both compressive and flexural tests of GMRA based geopolymers were conducted. It was found that the compressive strength of GMRA base geopolymer could reach 70 MPa at seven days. The influences of slag replacement ratio, alkali concentration and SiO2/Na2O ratio were investigated in this paper. The relation between the compressive and flexural strength for GMRA based geopolymer was also proposed through the fitting of the test data. Besides, the environmental impact and cost-benefit analysis of GMRA based geopolymer were quantitively studied, and results showed that increasing slag replacement ratio would dramatically reduce the CO2 intensity and the cost efficiency of GMRA based geopolymer. However, slight effect of alkali concentration on the CO2 intensity and cost efficiency was observed. (c) 2020 Elsevier Ltd. All rights reserved.