Quantitative determination of processed waste expanded perlite performance as a supplementary cementitious material in low emission blended cement composites

Abstract

Ground waste expanded perlite (WEP) is a new pozzolanic supplementary cementitious material of high activity. The use of effective reactive additions allows for a further reduction of the clinker content in the cement while maintaining the strength and durability of the mortars. This is the potential to further reduce the carbon footprint of cement. In the present work, the activity of ground waste expanded perlite was quantified using the k-value concept introduced by the EN-206 European standard for Type II additions. Two methods of k-value determination were used, based on the strength of mortars without and with ground WEP. Mortars made of ordinary Portland cement, as well as blended cements containing up to 80% of granulated blast furnace slag, were investigated in the study. Results showed that a 15% replacement of cement by ground WEP did not cause a decrease in strength. The results obtained showed that k-value equal to 1.0 may be attributed to ground perlite. Carbonation depth measurements revealed that the influence of ground waste expanded perlite on carbonation resistance was similar to the influence of silica fume. In mortars made from cements containing up to 60% of slag, incorporation of ground WEP increased carbonation depth by approximately 1 mm. For cement with 80% slag, the increase in carbonation depth was almost 5 times higher. It was found that the addition of ground waste expanded perlite activates high slag volume cements (CEM III/A and CEM III/B), however, due to increased carbonation, use of ground WEP with cements containing more than 60% of slag should not be appropriate.