ABSTRACT Cement is the third most energy –intensive material to produce, behind steel and aluminum. The production of every tonne of Portland cement contributes about one tonne of carbon dioxide (co2) into the atmosphere. Use of reclaimed and recycled industrial by-products, such as supplementary cementing materials (SCMs) to partially replace Portland cement in concrete, reduces green house gas GHG emission and results in sustainable “green “concrete. Additional benefits include minimization of waste disposal for these industrial by-products and lessened pressure on natural resources (such as limestone and iron ore), importantly, concrete using SCMs will generally exhibit an extended service life over conventional concrete. In order to promote the wider use of SCMs in concrete and to enhance consistent application and performance of  the technology such that an increase in GHG emission reduction can be achieved, this project report on the use of SCMs in concrete construction has been developed. The objective of this document is to provide basic knowledge in the use of SCMs in concrete, and the impact of SCM on construction. This project was carried out using coal ash as a partial replacement of cement and some tests were perfomed to examine the effect of this on concrete quality. Varying percentage from 50%, 40% and 30% replacement pattern was adopted and test like sieve analysis, compressive strength test, slump test concrete cube test performed. The replacement pattern shown that a 30% replacement of coal ash with cement is more sustainable among  the other replacement patterns.