Plasterboard and gypsum waste in a novel cementitious binder for road construction

Cements are substances which set and harden and can be used to bind other materials together. They are used throughout the construction industry, in a wide variety of applications, such as concrete. Gypsum is a key component in cementitious products and comes from a range of natural and synthetic sources as a by-product of industrial processes. Alternatively, recycled gypsum from waste plasterboard also has the potential to be used in cements. Interest in finding alternatives to landfill for plasterboard and other waste gypsum products has increased with the escalating costs of disposal and their reclassification as non-hazardous non-inert waste. Coventry University in collaboration with Skanska and Lafarge Plasterboard recently undertook a WRAP (Waste and Resources Action Programme) funded research to develop a cost effective novel binder using recycled gypsum from waste plasterboard and a range of mineral wastes for construction of road foundations. This chapter gives details of this investigation on potential use of plasterboard gypsum in combination with a range of mineral wastes in road bases, sub-bases and stabilised sub-grades

The impact of variation in chemical and physical properties of PFA and BPD semi-dry cement paste on strength properties

The effect of Pulverised Fuel Ash (PFA) and By-Pass-Dust (BPD) in ternary semi-dry cement pastes was reported. As well as this, the variability over 6 months in chemical composition and particle distribution was reviewed to determine impact on strength. The addition of BPD in ternary pastes resulted in a reduced strength when combined with PFA. PFA and BPD samples obtained over a 6 month period showed variability in both chemical composition and particle distribution. For PFA, it was reported that at 14 days the particle size distribution had greatest impact on strength and at 28 days the SiO2 content had greatest impact. The high variability in BPD particle size distribution resulted in finer particles achieving the greatest strength