Application of High Content of Volcanic Ash in High Strength Concretes

Fly ash is widely used in the world as a mineral admixture in high strength flowing concretes, but fly ash not produced in Azerbaijan, so it is necessary to use natural pozzolana like volcanic ash instead of fly ash. In this research, 20% of cement containing 7% of intergrinded volcanic ash were replaced by Balakhany volcanic ash grinded up to 4000 cm2/gram and 5000 cm2/gram Blaine values and fly ash with the Blaine of 2428 cm2/gram from Turkey and used in C40/50 class flowing concrete. Totally, 4 concrete mixtures were prepared. Target initial flow diameter of concretes was 65±2cm. Slump flow retention was measured after 30, 60 and 90 minutes. After 90 minutes the flow losses were between 1-5 cm. 28 days concrete strength results show that volcanic ash with the Blaine value of 5000 cm2/gram is very close to that of the reference mixture. Complex Performance Testing System (CPTS) mortar mixer was used to determine the water demand of cement mortar phase of the C40/50 concretes were determined, and stiffening of the mortars with penetration depth test was also tested. Hydration heat of each mortar phase was measured with the semi-adiabatic container to compare heat development up to 48 hours. It can be concluded that high content of volcanic ash can be used in high strength flowing concrete production without any strength loss. Reduced hydration heat can be an advantage in mass concretes.