Durability properties of cement – saw dust ash (SDA) blended self compacting concrete (SCC)

This paper report the durability properties of self-compacting concrete (SCC) modified with Saw dust ash (SDA) exposed to an aggressive media. Saw dust ash (SDA) was used to partially replace OPC in SCC at 0 - 30%. A number of trials mixes were conducted to obtain grade 40 SCC, with a suitable mix proportion varied at 5, 10, 15, 20, 25 and 30 % by weight of the binder as OPC replacement in SCC. Constant water to binder ratio of 0.37 with water reducing admixtures was used in all the mixtures. The research reveals that SDA enhanced the resistance of SCC against Na2SO4 attack at 5% replacement but performed poorly in H2SO4. The water absorption of SCC decreases with an increase in SDA content. The resistance of SDA-SCC to elevated temperature is reduced with an increase in SDA content. The compressive strength of the SDA-SCC decreases with the age of exposure in an aggressive media. The SEM result revealed the presence of crystal like spikes of SDA particles, which may contribute significantly to the high surface area of the ash particles and results in a porous structure at an early age.