Study on Flexural Behaviour of Activated Fly Ash Concrete

Cement concrete is the most widely used construction material in many infrastructure projects. The development and use of mineral admixture for cement replacement is growing in construction industry mainly due to the consideration of cost saving, energy saving, environmental production and conservation of resources. Present study is aimed at replacing cement in concrete with activated fly ash. The paper highlights the chemical activation of low calcium fly ash. Today activation of fly ash is playing an important role for enhancing the effectiveness of fly ash and accelerating the pozzolanic properties of fly ash. Activated fly ash certainly improves the early age strength and durability of concrete and corrosion tolerance. Many methods such as mechanical (physical), thermal and chemical activation are in use to activate the fly ash. The chemical activation is one of the easiest methods where fly ash can be activated by alkaline activators (i.e. alkaline solutions of high alkaline concentration chemicals like gypsum, sodium silicate and calcium oxide, KOH, etc.), which enhances the effectiveness of fly ash by disintegrating the glassy layer of fly ash molecules in cement concrete, thereby increasing its corrosion resistance. In the present dissertation, quality of fly ash is improved by chemical treatment by using chemical activators. The mechanical properties like compressive strength, split tensile strength, flexural strength of activated fly ash concrete and flexural strength of activated fly ash reinforced concrete beams are studied. For this project work, the chemicals like sodium silicate, calcium oxide are used to activate the fly ash in the ratio 1:8.