Experimental Study on the Influence of Polypropylene Fiber on the Swelling Pressure Expansion Attributes of Silica Fume Stabilized Clayey Soil

Abstract

Expansive soil shows dual swell-shrink which is not suitable for construction. Several mitigating techniques exist to counteract the problem promulgated by expansive clayey soils. This paper explored the potential mecho-chemical reinforcement of expansive clayey soil to mitigate the effect of upward swelling pressure and heave. The polypropylene fiber is randomly distributed in the soil for mechanical stabilization, and the industrial residual silica fume is used as a chemical stabilizer. The experimental analysis was made in three phases which involved tests on mechanically-reinforced expansive soil, using randomly distributed polypropylene fibers with different percentages (0.25%, 0.50%, and 1.00%), and which were 12 mm length. The second phase of experiments was carried out on chemical stabilized expansive soil with different percentages (2%, 4%, and 8%) of silica, and the next phase of the experiment focused on the combination of mecho-chemical stabilization of the expansive soil with different combinations of silica (i.e., 2%, 4%, and 8%) and polypropylene fibers (i.e., 0.25%, 0.50%, and 1.00%). Maximum dry density (MDD), optimum moisture content (OMC), liquid limit (LL), plastic limit (PL), plastic index (PI), grain size, and constant volume swelling pressure tests were performed on unreinforced and reinforced expansive soil, to investigate the effects of polypropylene fiber and silica fume on the engineering properties of expansive clayey soil. The experimental results illustrate that the inclusion of polypropylene fiber has a significant effect on the upward swelling pressure and expansion property of expansive soil. The reduction in the upward swelling pressure and expansion is a function of fiber content. These results also indicated that the use of silica fume caused a reduction in upward swelling potential, and its effect was considerably more than the influence of fiber.

Effect of Curing on Micro-Physical Performance of Polypropylene Fiber Reinforced and Silica Fume stabilized Expansive Soil Under Freezing Thawing Cycles

“…The four types of samples have been prepared to investigate the effect of curing methods on freezing-thawing cycle of PP fiber-reinforced, and silica fume stabilized expansive soil: (1) an untreated sample; (2) an SF stabilized sample; (3) a PP Fiber-reinforced samples, and (4) a PP fiber-reinforced and SF stabilized sample. The expansive soil has been reinforced with 0.25%, 0.50%, and 1.00% PP fiber and stabilized with 2%, 4%, 6%, and 8% SF as reported by Tiwari and Satyam (2019) 63 . The expansive soil samples were air-dried until a stable state was reached.…”

“…The chemical stabilization is a substantiate quick-fix method to improve the shear strength and also reduces the swelling shrinkage nature of expansive soil [24][25][26][27] . Nonetheless, there are substantial problems for the long-term viability of these approaches, depending on soil clay mineralogy, ecological variations in clay 19 .…”

“…The various industrial waste by-products have manifested to chemically stabilized the expansive soil. A silica fume is one of the non-expansive industrial waste materials that significantly improves the strength and reduces upward swell pressure in expansive soil subgrades 26 . Nevertheless, SF is a byproduct of industrial waste material, and its open disposal is a serious concern for air pollution.…”

“…The various advantages of the PP fiber with silica fume stabilized expansive soil has been presented in the literature. Nitin et al 2019, explained the effect of SF and PP fiber inclusion with BC soil to reduce the upward swell pressure and its mitigation mechanism 63 . However, the coupling behavior of soil, SF, and PP fiber at the microstructural level and for durability assessment is not present.…”

Hybrid bacteria mediated cemented sand: Microcharacterization, permeability, strength, shear wave velocity, stress-strain, and durability

“…Recently, conventional methods are replaced by advanced emerging techniques for improving the properties of granular soils. The use of supplementary cementitious materials, nanomaterials, synthetic fibers, industrial waste products, and biopolymers are found effective for strength enhancement (Huang and Wang 2016; Tiwari and Satyam, 2019, 2020; Tiwari et al., 2020a, 2020b, 2020c). However, the high cost of treatment and field application of these methods are the major challenges.…”