Improved performance in low clinker content cements containing construction and demolition waste as a pozzolanic material

The manufacture of cements bearing a high percentage of active additions is a trend that has been spurred by the benefits accruing from the reduction of clinker content. The availability of traditional natural pozzolans is ebbing, however, due to a decline in quarrying intensity aimed at minimising the impact on the landscape. At the same time, environmental policies seek to reduce or eliminate spoil heaps by valorising industrial waste and by-products as raw materials, in keeping with circular economy principles. For those reasons, the pursuit of alternative pozzolans constitutes a priority line of research. In earlier studies, the authors found that fired clay-based construction and demolition waste (C&DW) exhibited good pozzolanicity, despite its fairly low early age activity. The present study discusses the substantial improvements in pozzolanic performance when C&DW was combined with no more than 5 % silica fume.

Author: M.I. Sanchez de Rojas, E. Asensio, M. Frias, I. Cuevas, C. Medina

Section: Waste utilization

Keywords: cements, pozzolanic activity, supplementary cementitious materials, ceramic waste