Properties of Concrete Containing Large Volumes of Ground Granulated Blast Furnace Slag and Ground Coal Bottom Ash with Lime Kiln Dust

Abstract

Currently, there is no report on the combined use of ground coal bottom ash (GCBA) and ground granulated blast furnace slag (GGBS) as supplementary cementitious material (SCM) with lime kiln dust (LKD) as an additive in mortar. Hence, the current work aimed to investigate the impact of the addition of LKD on the properties of ternary blended cement mortar consisting of a large volume of GCBA and GGBS as SCM. The total substitution level of cement was up to 80%, where 50% of GGBS was combined with 0 to 30% of ground CBA. LKD was used with a content of 0%, 4% and 8%. A polycarboxylate-ether-based superplasticiser was used to achieve the mortar’s flow diameter of 200 ± 10 mm. Also, the fine aggregate-to-binder and water-to-binder ratios were fixed at 3.0 and 0.4, respectively. The result revealed that the setting time of the mortar increased by increasing the cement replacement level by GCBA. Besides, the setting time was reduced with increased LKD content. All the mortar mixtures are considered good quality according to the ultrasonic pulse velocity (UPV) results. The UPV values decrease with the increased GCBA replacement ratio but increase with extended curing ages. The mortar incorporating up to 15% GCBA achieved comparable or greater strength than the control mortar (50% OPC and 50% GGBS) at a curing age beyond 28 days. Moreover, increased strength performance was noticed with increased LKD content from 0% to 8%.