Static and Dynamic Properties of Controlled Low-Strength Materials Incorporating Treated Oil Sands Waste

Controlled Low-Strength Materials (CLSM) is a self-compacted self-leveling cementitious material with compressive strength of 8.3 MPa or less. It is used as an alternative of soil backfill materials in geotechnical and infrastructure applications. This study investigates the effects of incorporating treated oil sand wastes (TOSW) as a partial replacement of sand or fly ash on fresh and hardened properties of CLSM. In addition, the environmental impact of the proposed new mixtures was evaluated. The results show that CLSM mixtures incorporating TOSW had satisfied the limits and requirements of ACI committee 229 for CLSM with no environmental hazards. The incorporation of TOSW has increased the flowability of all mixtures and consequently reduced the water demand to reach the required flowability which consequently increased the compressive strength of mixtures containing TOSW and fly ash. Replacing fly ash with TOSW on the other hand, reduced the strength of CLSM slightly, but the strength remains within CLSM acceptable range of strength. In addition, this produced a more re-excavatable mixture, adequate for applications that may require future re-excavation. To investigate the effects of incorporating TOSW in CLSM as a replacement of fly ash and partial replacement of sand on its dynamic properties, shear wave velocity and geo-mechanical properties were evaluated. The piezoelectric ring actuator (PRA) technique was employed for measuring Vs of CLSM and an empirical equation was suggested to estimate Vs based on mixture proportions of CLSM. The results suggest that the shear wave velocity was affected primarily by the cement content, while TOSW had minimal impact on it. However, TOSW improved the flowability of the mixture and could totally replace fly ash for that function. It is concluded that TOSW can be successfully incorporated in CLSM mixtures, offering an application to reduce the landfill disposals of oil sands waste while reducing the demand on natural resources