Effect of Oil Shale Residue on Compressive Strength and Chloride Corrosion Resistance of Concrete

A huge amount of oil shale residue is left after retorting or burning of oil shale. The dumping of oil shale residue occupies land resources and seriously pollutes the environment. Oil shale residue concrete(OSRC) was prepared with oil shale retort residue as coarse aggregate. The workability, microstructure, compressive strength and chloride ion permeability of OSRC were tested. The results showed that the workability, mechanical properties and chloride corrosion resistance of OSRC decrease with the increase of oil shale residue replacement(Vr). When Vr is 25% and 43%, the cubic compressive strength of OSRC is 29.9 MPa and 25.5 MPa, and the chloride ion permeability is respectively evaluated as very low and low. While Vr is greater than 50%, the electric flux of OSRC increases rapidly with the increase of Vr, so 50% is the critical Vr of OSRC chloride ion permeability. It was found that the farther away from the boundary between the OSR and the interface transition zone (ITZ), the fewer ettringite crystals and more calcium silicate hydrate gel in ITZ, and there is very little calcium hydroxide crystals in whole ITZ. OSR has water absorption and desorption characteristics. In addition, the compressive failure mode of OSRC is OSR fracture with smooth fracture surface and cement mortar spalling around natural aggregate. Finally, OSR and ITZ are the weak areas of OSRC, which are the key to the follow-up research. And porous wastes such as OSR could be used as concrete fillers and internal curing materials. © 2021, Materials Review Magazine. All right reserved.