effect of addition of calcium nitrate on selected properties of concrete containing volcanic ash

In this work, the effect of addition of Calcium Nitrate on selected properties of concrete containing Volcanic ash as partial replacement for ordinary Portland cement by weight was investigated .The study carried out used 10% volcanic ash as partial replacement and an admixture, Ca(NO3)2 Was added to improve the strength of the resulting concrete at 2%, 4%, 6% 8% and 10% respectively. The result of setting time showed a decrease in both initial and final setting time of the mixture as the Ca(NO3)2 Content was increased. The result of chemical analysis of volcanic ash showed an increase in calcium oxide (CaO) content when calcium Nitrate Ca(NO3)2 was added from 11.67% to 33.68%. Cubes were cast and cured in water for 7, 14, 21, and 28 days .The resulting Strength at 28 days hydration period shows a strength increase as the percentage of Ca(NO3)2 was increased to 10%.