Fresh Behavior and Hardened Properties of Self-Compacting Concrete Containing Coal Ash and Fly Ash as Partial Replacement of Cement

Abstract

Due to the higher price of cement compared to other concrete ingredients, the problems associated with greenhouse gases emissions during its production and its high popularity have arisen concerns in its substitution with other supplementary cementitious materials (SCMs). In this regard, the current experimental program was established to investigate the fresh and hardened performance of self-compacting concrete (SCC) made with coal ash (CA) and fly ash (FA) as fractional substitution of cement. In this paper an attempt was made to use the remaining CA from the barbecue process of the restaurants from Fallujah city, Iraq. A total number of 7 concrete mixes were prepared with unchanged (w/b) ratio of 0.37 and total cementitious content of 450 kg/m3. Reference mix was produced by using 100% cement without FA or CA. Then, other mixtures were batched with 10%, 20% and 30% (by weight) replacement of cement by FA and CA, respectively. The results illustrated that, in contrast to the FA, the CA has negative influences on the fresh properties of SCC but the results still meet the criteria for the fresh behavior of SCC. On the other hand, the inclusion of CA was significantly improved the strength and water absorption of SCC. Sustainable high strength SCC can be produced due to the addition of CA.