Calcined oil shale residue as a supplementary cementitious material for ordinary Portland cement

Oil shale residue (OSR), a ubiquitous by-product of crude oil processing, is usually stacked on the surface and will pollute the environment. In this study thermal activation technology was used to increase the pozzolanic reactivity of OSR, which was used as supplementary cementitious materials (SCM). Different calcination temperature (500, 600 and 700℃) was carried out to discussed the transformation of mineralogy of OSR, after which, the pozzolanic reactivity test was carried out and the hydration products of OSR were analyzed. Finally, the OPC was replaced with OSRs varied from 10% to 50% by weight to analyze the fresh and mechanical behavior of the samples. The results showed that a number of potentially activatable clay minerals content in the OSR such as kaolinite, montmorillonite and illite, calcining OSR at 500–700℃ can improve pozzolanic reactivity and the optimal calcination temperature is about 600℃. The compressive strength of OSR/OPC composites material increased by around 8% (curing for 3 d) and 11% (curing for 28 d) using OSR (calcined at 600℃ and replacement rate at 10%) as SCMs.