Life cycle assessment of geopolymer concrete: a Malaysian context

The production of Portland cement is well acknowledged as having as significant impact on the environment, accounting for 8% of global CO₂ emissions (4bn tonnes per annum). Concrete is the most widely used material in the world and therefore has vast potential to absorb high volumes of waste and by-product materials. These materials can act as partial replacements as supplementary cementitious materials or total replacements and perform as binders in geopolymer concretes. The use of Pulverised Fuel Ash (PFA) from coal-fired electricity generating stations to substitute Ordinary Portland Cement (OPC) is well established. Quantifying the potential environmental benefit of using such materials can be difficult. The life cycle assessment (LCA) methodology, internationally standardised through ISO14040 series, may be used to quantify the environmental impact of products and processes. This paper outlines the use of the LCA methodology to compare the environmental impact of OPC precast concrete products to PFA precast concrete products in a Malaysian context. The four stages of LCA are detailed and consequences of designating materials as a by-product or waste are discussed. A review of other LCA studies completed in Malaysia for the built environment are also presented so as to identify which impact assessment methods are most frequently used.