Application of Treated Oil Sands Drill Cuttings Waste in Micropiles Construction

A micropile is constructed by drilling a hole, placing a steel reinforcing element, grouting it using neat cement. However, cement production consumes energy and generates carbon dioxide. Implementing waste materials in construction applications represents a sustainable solution for many waste management problems. On the other hand, oil sands drill cuttings waste represents one of the most difficult challenges for the oil sands mining sector. Reducing the amount oil sands drill cutting waste sent to landfill offers one of the best solutions for waste management. This thesis presents an innovative solution for application of treated oil sands waste (TOSW) in grout mixtures used for micropiles construction. In this study, the physical, chemical and mineralogical characteristics of the treated oil sands drill cuttings waste were investigated. Fresh and hardened properties for micropiles grouts incorporating the treated solid drill cuttings waste were evaluated. Moreover, the effects of employing these grout mixtures on micropiles cross-section, surface interface properties and axial behaviour were investigated. The results showed that incorporating up to 20% of the treated solid drill cuttings waste as a partially replacement of cement will not adversely affect the properties of the grout. On the other hand, leaching tests evidenced the reduction in the release of heavy metals from the tested mixtures compared to that of the raw waste indicating successful stabilization/solidification of such waste in the grout. In addition, it was noticed an enhancement in the grout body diameter for micropiles installed using the developed grout, while maintaining the micropile surface properties. Moreover, micropiles installed using grout incorporating a high percentage of the TOSW (up to 30%) exhibited the same axial behaviour as that of micropile installed using conventional grout. Therefore, incorporating TOSW in micropile applications has high potential for producing cost efficient micropiles along with providing a green oil sands waste management solution