Geopolymer Technology: The Formation of Cost-Competitive Construction Materials by the Alkali-Activation of Coal Ash

摘要

Inorganic polymers (referred to as geopolymers) have emerged as novel engineeringrnmaterials with the potential to form the basis of a new and environmentally sustainablernconstruction materials and building products industry. These materials are formed byrnthe alkali activation of industrial by-products such as coal ash (Class F and/or Class C),rnand blast furnace slag. Geopolymeric materials derived from coal ash can exhibitrnsuperior chemical and mechanical properties to ordinary Portland cement (OPC)rncounterparts. In addition to the formation of conventional pre-cast or architecturalrnproducts, these high performance mineral binders are well suited for the encapsulationrnof mine tailings, the immobilisation of heavy metals, and the paste back-filling of mines.rnA key attribute to the technology is the robustness and versatility of the manufacturingrnprocess; it enables products to be tailor-made from a range of coal ash sources andrnother alumino-silicate raw materials so that they have specific properties for a givenrnapplication at a competitive cost (eg. High strength concrete; fire & acid resistantrncoatings etc). Despite these key technical and environmental attributes, it is the ability tornadd significant value to coal ash waste streams which drives the commercialrndevelopment and uptake of the technology. The present paper presents a backgroundrnto geopolymer science. The current challenges and obstacles faced by workers in therngeopolymer field as well as the commercial application of inorganic polymer technologyrnare highlighted and discussed.