Development of novel cementitious binders using plasterboard waste and pozzolanic materials for road bases

This paper explores the potential benefits of utilising combination blends of plasterboard waste gypsum and pozzolanic materials in developing novel cementations pastes with lower environmental impact in comparison with conventional Portland cement. Ternary blend systems based on waste plasterboard from construction demolishing sites (PG), basic oxygen slag from steel factories (BOS) and cement kiln dust (CKD)/by past dust (BPD) from cement industries were investigated. PG, up to 30%, BOS and CKD, up to 90% were incorporated as total binder replacements for preparation of various combinations of binary and ternary blended systems to achieve the highest compressive strength. A water-binder ratio of 0.3 was used for the main group of paste mixes. Cube compressive strength was determined at the age of 3, 7 and 28 days. Based on the obtained results, the effect of PG and CKD on activation of slag with respect to compressive strength was investigated. It was found that the relation between slag content and compressive strength is sensitive to the amount and chemical composition of PG and CKD/BPD used in ternary system. In ternary system of PG-BPD-BOS, incorporation of 10% PG together with 36% BPD resulted in the highest compressive strength while in CKD-PG-BOS system; the highest compressive strength is achieved using 20% CKD and 16% PG. A road foundation site trial was successfully conducted in summer 2006 using this developed binder for road base in a car park area at Lowdham Grange prison, Mansfield construction site.