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Silty soil performs poorly when used in roads. Cement is generally used as a stabilizer to treat silty soil and enable it to meet the requirements for roadbed filling. However, cement is an environmentally unfriendly material and can cost much. Meanwhile, solid wastes of ground granulated blast furnace slag (GBFS), fly ash (FA), and flue gas desulfurized (FGD) gypsum are produced in large quantities annually. Therefore, stabilizer A (cement:ground GBFS:fly ash:FGD gypsum = 30:44:15:11) and stabilizer B (cement:ground GBFS:fly ash:FGD gypsum = 40:38:13:9) were investigated in this study by reducing the cement content in the stabilizer and improving the utilization rate of solid wastes. The compressive strength development, California bearing ratio (CBR), temperature shrinkage, mineral composition, and micro-morphology of the stabilized silty soil were measured. The main findings are as follows: firstly, the addition of solid wastes can mitigate the adverse effect of delay time on compressive strength development. Secondly, the proposed stabilizers can significantly improve the CBR, which can reach 60% with a 4% dosage. Additionally, Stabilizer B is believed to improve the resistance to temperature shrinkage, and a higher stabilizer dosage can reduce the rate of decrease in water stability coefficient. Both X-ray diffraction analysis and scanning electron microscope observations show that the main hydration products that contribute to the stabilization are C-S-H and ettringite. [ABSTRACT FROM AUTHOR]

The addition of electric arc furnace slag and ladle furnace slag on strength improvement of lateritic soil was studied in this work. Liquid limit, plasticity index, and the California bearing ratio of lateritic soil mixed with the slags were determined in comparison to those of ordinary lateritic soil. A scanning electron microscope was used to confirm the effect of those two slags on microstructures related to chemical components of raw materials and the strength of lateritic soil. The deterioration of California bearing ratio, liquid limit, and plastic index values were obtained when the electric arc furnace slag was mixed in lateritic soil. Meanwhile, the California bearing ratio of lateritic soil was highly improved with the addition of ladle furnace slag, owing to the hydration reaction between water and excess lime in ladle furnace slag with free silica in lateritic soil. The values of the plasticity index were also comparable to the ordinary lateritic soil. Microstructures confirmed a highly compacted surface of mixed lateritic soil with ladle furnace slag. The ladle furnace slag is therefore one of the promising alternative low-cost materials for the soil-stabilizing application. [ABSTRACT FROM AUTHOR]