Abstract
Increased awareness of sustainability has resulted in the use of alternative supplementary cementitious materials in concrete construction. Volcanic ash (VA) is a prospective material available in the Gulf region that can be used to produce green and economical concrete. This paper reports the results of an elaborate study on the effect of incorporation of different percentages of VA on various mechanical and microstructural properties of hydrated cement paste with an objective to determine the optimal percentage of VA that can replace the ordinary portland cement (OPC) to obtain the maximum benefit. It is concluded from the studied mechanical and microstructural properties that an OPC replacement of 10-30% by VA brought out the maximum benefit. Further to this, the study confirmed that even though the incorporation of VA did not contribute positively towards strength development, a continuous and compact microstructure could be produced with an optimal percentage of VA.