Geopolymer Concrete – A New Eco-Efficient Material for Construction

Introduction

Today our environment is under stress .Our environment is polluted by various means.The one important effect of pollution is global warming.The main constituent of global warming is carbon di oxide.So during the manufacture process of OPC ,that to in calcination of limestone and combustion of fossil fuel ,a amount of the carbon dioxide is released. Globally, the world’s Portland cement production contributes to about 1.6 billion tons of CO2 (or) 7% of global loading of CO2 into the atmosphere. By the year 2010, World cement consumption is expected to reach about 2 billion tones means 2 billion tonnes of CO2 will be released. The above issues can be addressed by finding a alternative way of binder to make concrete . Geopolymer Concrete is one of the solution .

Geopolymers

The term ‘geopolymer’ was first introduced by Davidovits in 1978 to describe a family of mineral binders with chemical composition similar to zeolites but with an amorphous microstructure. Unlike ordinary Portland/pozzolanic cements, geopolymers do not form calcium- silicate-hydrates (CSHs) for matrix formation and strength, but utilise the polycondensation of silica and alumina precursors to attain structural strength. Two main constituents of geopolymers are: source materials and alkaline liquids. The source materials on alumino-silicate should be rich in silicon (Si) and aluminium (Al). They could be by-product materials such as fly ash, silica fume, slag, rice-husk ash, red mud, etc. Comparison of conventional and geopolymer cement is shown in figure

Advantage of geopolymer concrete

Geopolymer concrete is more resistant to corrosion and fire, has high compressive and tensile strengths, gains its full strength quickly (cures fully faster) ,low creep, no shrinkage, good acid resistance, low permeability, resistance to sulphate attack and Durable Finishes.

Application of geopolymer concrete

Used in industrial floor repairs, Airfield repairs (in war zones) ,Bathroom fittings & Furniture, fireproof composite panels, External repair and structural retrofit for aging infrastructure, For storage of toxic and radioactive wastes, Potential utilizations in Art and Decoration ,LTGS Brick, railway sleepers, electric power poles ,Marine structures, Waste containments etc..

Concluding Remarks

Geopolymer concrete shows significant potential to be a material for the future; because it is not only environmentally friendly but also possesses excellent mechanical properties. Practical recommendations on use of geopolymer concrete technology in practical applications such as precast concrete products and waste encapsulation need to be developed in Indian context.

Because of lower internal energy (almost 20% to 30 % less) and lower CO2 emission contents of ingredients of geopolymer based composites compared to those of conventional Portland cement concretes, the new composites can be considered to be more eco-friendly and hence their utility in practical applications needs to be developed and encouraged.