Experimental investigations on the properties of controlled low-strength material

Controlled low-strength materials (CLSMs) are self-compacting and cementitious fluid-like materials that flow freely under their own weight. They are often used in backfill, pavement bases, structural bases, utility embedment, void-fill, trenching and repair-fill applications. Pavement infrastructure built on CLSM fills often experience distress owing to high settlements and related CLSM cracking as well as CLSM failure during the service life. A research study was initiated to address quality control and assessments of certain proprietary type CLSMs produced in the field. This research showed that both strength and flowability properties of CLSMs supplied by the vendors did not meet the targeted property requirements, although they were advertised to have high design properties. Production of CLSMs by various operators also resulted in the variability of the CLSMs produced in the field. Density, flow and excavatability characteristics of CLSMs are analysed to address the performance-related behaviours of these materials. Statistical variations of CLSMs with respect to vendor, operator and application area were addressed through statistical t-test analysis. Recommendations for better quality assessment practices to evaluate CLSMs are also provided.