Behaviour of self compacting concrete using Portland pozzolana cement with different levels of fly ash

The influence of including fly ash (FA) on the properties of self-compacting concrete (SCC) is investigated. Portland pozzolana cement (PPC) was partially replaced with 10–70% fly ash. The water to binder ratio was maintained constant at 0.30 for all mixes. Properties included were self-compactibility properties (slump flow, V-funnel time and L-box blocking ratio) mechanical properties (compressive strength, splitting tensile strength and elastic modulus), and durability properties (water absorption, water penetration depth and chloride permeability). The results indicate that fly ash along with PPC can be used in SCC to produce high strength high performance concretes. Replacing 30% of PPC with FA resulted in strength of nearly 100 MPa at 56 days. Splitting tensile strength and elastic modulus values have also followed the same trend. High absorption values were obtained with increasing amount of FA, however, all the SCCs exhibited initial absorption values of less than 3%. The water penetration depths in SCCs were lower at 10% and 30% replacements of fly ash but remained higher at 50% and 70% replacements. There is a systematic reduction in the chloride permeability of SCCs at 30% replacement of fly ash.

► Fly ash replacements of around 30–50% will be ideal for developing SCCs when Portland pozzolana cement (PPC) was used. ► Thirty percentage replacement of fly ash exhibited the highest compressive strength, splitting tensile strength and elastic modulus. ► The absorption and water penetration depths in SCCs increase with increasing fly ash content. ► Thirty percentage of replacement fly ash in SCC exhibited the highest chloride penetration resistance.