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Effect of Chemical and Biological Stabilization on the Resilient Modulus of Clay Subgrade Soil
According to the geotechnical section of the Kyoto Protocol, researches on nontraditional materials such as polymers and new methods like biological soil stabilization have been developed. This study aimed to investigate and compare the effect of chemical and biological stabilization of clay subgrade soil. For chemical stabilization, polymers called cationic polyelectrolyte (CPE) and Nicoflok were used. For biological stabilization, the microbial-induced calcium carbonate precipitation (MICP) method was adopted and a biopolymer solution called Beta-glucan was employed. In both methods, the dry density of the soil decreased and its optimum water content and pH increased. The Plastic Limit of the soil increased after stabilization with CPE and decreased in stabilization with other stabilizers. All four additives increased the uniaxial compressive strength and the elasticity modulus of the soil. The effect of Nicoflok and biopolymer was more evident. Despite similar results in the uniaxial test, the increasing effect of Nicoflok on the resilient modulus (MR) was more than that of the biopolymer. Raising the dose of these two stabilizers and also the curing time changed the resilient behavior of the fine-grained soil to coarse-grained under different stress conditions. Nicoflok and biopolymer-stabilized samples exhibited a higher California bearing capacity (CBR) and durability compared to the untreated sample, with the effect of Nicoflok being more significant. The estimate of design MR for these samples using the stress-dependent model was more accurate compared to the conventional correlations with CBR. Therefore, chemical stabilization with the Nicoflok is economically feasible, while biological stabilization using the biopolymer is environmentally suitable for the studied soil.
Effect of Chemical and Biological Stabilization on the Resilient Modulus of Clay Subgrade Soil
According to the geotechnical section of the Kyoto Protocol, researches on nontraditional materials such as polymers and new methods like biological soil stabilization have been developed. This study aimed to investigate and compare the effect of chemical and biological stabilization of clay subgrade soil. For chemical stabilization, polymers called cationic polyelectrolyte (CPE) and Nicoflok were used. For biological stabilization, the microbial-induced calcium carbonate precipitation (MICP) method was adopted and a biopolymer solution called Beta-glucan was employed. In both methods, the dry density of the soil decreased and its optimum water content and pH increased. The Plastic Limit of the soil increased after stabilization with CPE and decreased in stabilization with other stabilizers. All four additives increased the uniaxial compressive strength and the elasticity modulus of the soil. The effect of Nicoflok and biopolymer was more evident. Despite similar results in the uniaxial test, the increasing effect of Nicoflok on the resilient modulus (MR) was more than that of the biopolymer. Raising the dose of these two stabilizers and also the curing time changed the resilient behavior of the fine-grained soil to coarse-grained under different stress conditions. Nicoflok and biopolymer-stabilized samples exhibited a higher California bearing capacity (CBR) and durability compared to the untreated sample, with the effect of Nicoflok being more significant. The estimate of design MR for these samples using the stress-dependent model was more accurate compared to the conventional correlations with CBR. Therefore, chemical stabilization with the Nicoflok is economically feasible, while biological stabilization using the biopolymer is environmentally suitable for the studied soil.
Effect of Chemical and Biological Stabilization on the Resilient Modulus of Clay Subgrade Soil
Int. J. Pavement Res. Technol.
Moradi, Gholam (author) / Shafaghatian, Siamak (author) / Katebi, Hooshang (author)
International Journal of Pavement Research and Technology ; 15 ; 415-432
2022-03-01
18 pages
Article (Journal)
Electronic Resource
English
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