Engineering properties of soil-based controlled low-strength materials as slag partially substitutes to Portland cement

This study aim is to examine on the engineering properties of soil-based controlled-low strength material (CLSM) containing blast furnace slag cement as cement substitute and residual soil as aggregate. By conducting an experimental program, twelve CLSM mixtures made with blast furnace slag partially replace for Portland cement of 10%, 20%, and 30% by weight and three sand–soil combinations, e.g. sand–soil proportion of 6:4, 5:5, and 4:6. The engineering parameters of CLSM, such as slump flow, setting time, ball-drop value, compressive strength, pulse velocity, and modulus of reaction subgrade were determined in according with ASTM procedures. Testing results indicate that the proposed mix proportion are almost met the requirements of excavatable CLSM. In addition, with slag replacement to cement would effectively improve the flowability, significantly delay setting time, and noticeably reduce compressive strength, pulse velocity under water-to-binder ratio being fixed. Moreover, the findings also exhibit that an increase in soil content in composition could lead to affect obviously on the CLSM’s performances. Furthermore, an exponential formula was also successfully established based on experimental data to express the relationship between compressive strength and ultrasonic pulse velocity, from 01 to 91 days. Finally, as regards geotechnical property, the applied load–deflection curves for CLSM have been plotted and thereby the modulus of reaction subgrade reaction was further estimated.