Reuse of industrial by-products in building material INDUSTRY
The development and application of concepts such as “zero waste”, the “circular economy”, “industrial ecology”, and “resource efficiency” in 21th century economies requires the development of new Eco-innovative BMs. An emerging field in BM is the development of different inorganic polymers derived by the reaction of an alkali metal source with a solid silicate powder, called geopolymers. These geopolymers can be formed at room temperature by using wastes or by-products e.g. PFA, GGBS and CKD as source materials to form a solid-binder that looks like and performs a similar function to OPC (Ordinary Portland Cement). For example, CKD presents a significant waste disposal (to landfill) problem for the cement industry, with an estimate of 500k tonnes annually across the EU. Direct Economic benefits will accrue to the cement producing companies through the savings in CKD disposal costs (in the range £100 per tonne) and increased revenue margin from low CO2 product lines. Geopolymers can be used to fully or partially replace OPC with a lower carbon footprint (80 – 90% reduction in CO2 emissions). In comparison to OPCs, geopolymer concrete has better resistance to corrosion and fire, high compressive and tensile strengths, a rapid strength gain, lower shrinkage and longer durability. In new type of geopolymers, the toxic components among them the artificial or the natural radioisotopes can be stabilized as a result of their low migration, which provides excellent opportunity beside construction materials to develop geopolymer matrix suitable for e.g. radioactive waste cementization.