Development of sustainable substitutes for Pulversized Fly Ash in Cement and Concrete

Blended cements are formed from a mix of ordinary cement and another cementitious material, known as clinker substitute. These alternative materials are frequently used in the cement and concrete industries to: (1) reduce CO2 emissions associated with production; (2) improve physico-chemical properties and performance; and (3) reduce costs. Pulverised fly ash (PFA), a fine waste residue produced in coal-fired power stations is commonly used as a l clinker substitute in Portland cement. It provides significant environmental and cost benefits through (1) reduced energy demands for production and (2) use of waste product that would alternatively go to landfill. In addition, the use of PFA blended cements in concrete can improve strength and durability. However, the supply of PFA is declining, and costs increasing. Coal-fired power stations are shutting down, to reduce CO2 emissions it is expected that there will be no UK supply of PFA beyond 2025.

This PhD project, in collaboration with Low Level Waste Repository Ltd (LLWR), aims to identify sustainable, cost-effective substitutes for PFA, for use in blended cements. . LLWR is responsible for the safe disposal of low level radioactive waste in the UK. Their operations are critically dependent on blended cements containing PFA, for safe encapsulation and containment of the waste in engineered vaults. The project aims to will study a range of alternative, sustainable materials to replace PFA, investigating the physical, chemical and mechanical properties of the blended cements and assessing their performance and suitability for industrial use.