Production of More Sustainable Mortar Using Finer Volcanic Scoria-based Blended Cements

Use of natural pozzolan is growing rapidly in the construction industry due to its economical, ecological and technical benefits. However, they are often associated with shortcomings such as the need to moist-curing for longer time and a reduction of strength at early ages. Syria is relatively rich in volcanic scoria. The objective of the study is to investigate the effect of Blain fineness of cement on the strength development of scoria-based cement mortars. In the study, mortar specimens have been produced with four types of cement: one plain Portland cement (control) and three scoria-based blended cements with three replacement levels: 25, 30% and 35%, respectively. All blended cement types have been interground into four different Blaine fineness: 2400, 3200, 4200 and 5100 cm2/g. The development of the compressive and flexural tensile strength of all mortar specimens with curing time has been investigated. The effects of the Blaine fineness of the scoria-based blended cement on the compressive and flexural strengths of mortar have been evaluated at curing ages of 2, 7, 28 and 90 days, respectively. Test results revealed that there is a decrease in strength with increasing amounts of scoria. In addition, there was found an increase in strength with increasing the Blaine fineness values. Good correlations between mechanical strengths and Blaine fineness have also been observed at different curing times. Further, based on the results obtained, an empirical equation was derived to predict the mechanical strengths of scoria-based cement mortars with curing times based on Blaine fineness. Effects of Blaine fineness on some physical properties of blended cements have been reported, as well