Geopolymer Concrete: Opportunities, Limitations and Future Needs

Introduction

Portland cement concrete is the key construction material for all the development activities across the world. The concrete industry is the single largest consumer of the natural resources i.e. rocks, sand, and water. Each one of the constituent material of concrete has some adverse effects on the environment1. The manufacturing of the main constituent of concrete i.e. Portland cement is responsible for emission of about 6% of the total global anthropogenic carbon dioxide gas that is the key greenhouse gas held responsible for the global warming and climate change2-3. Compounded with the faster rates of depletion of materials needed for the manufacturing of Portland cement and good quality aggregates, concrete industries give rise to sustainability issues. On the other hand, there are ample possibilities for recycling of suitable industrial by-product materials for their high-volume high-end utilization in the concrete industry4. In light of the above facts, wide-spread innovative researches are being carried out all over the Globe for the high-valued utilization of suitable industrial by-products for the high-volume or complete replacement of the Portland cement from the concrete. Geo-polymer concrete (GPC) is a recent attempt in this direction. Natural or/and artificial pozzolans when combined with suitable alkaline activators yields to geopolymer which is used for binding aggregates to produce concrete for a wide range of applications. Concrete manufactured in this way is popularly known as geopolymer concrete. In last few decades, considerable interest has been generated in this concrete, particularly in light of today's burning issues i.e. sustainability and reduction of green house gas emissions from cement-based industries, responsible for global warming. The technology of geopolymerisation is not new and has been used in the construction of the Pyramids at Giza and other ancient civilizations structures5-6.