1- PhD Student, Department of Civil Engineering, Isfahan (Khorasgan) Branch, Islamic Azad University, Isfahan, Iran
2- دانشیار، گروه مهندسی عمران، واحد نجف آباد، دانشگاه آزاد اسلامی، نجف آباد، ایران , bayat.m@pci.iaun.ac.ir
3- Associate Professor, Department of Civil Engineering, Isfahan (Khorasgan) Branch, Islamic Azad University, Isfahan, Iran
Abstract: (37 Views)
Soil stabilization techniques have traditionally relied on cement or lime, yet there remains a significant knowledge gap regarding the mechanical behavior of soil treated with innovative materials. Addressing this gap, this study delves into the mechanical properties of soil stabilized with polyurethane (PU) foam, nano-silica, and basalt fiber. Through rigorous experimentation, unconfined compressive strength (UCS) and direct shear tests were conducted on reconstituted silica and calcareous samples, each treated with various combinations of these additives. A comprehensive examination of parameters such as additive content and curing time was undertaken to elucidate their effects. The results unveiled a noteworthy enhancement in UCS and shear strength parameters (cohesion and friction angle) with the incorporation of PU foam, nano-silica, or their amalgamation with fiber. Particularly striking was the superior performance observed with the combination of PU and basalt fiber, showcasing remarkable improvements in the mechanical behavior of both silica and calcareous sand, especially when considering shorter curing times. The synergistic effects of PU and basalt fiber proved instrumental in fortifying the soil's structural integrity against environmental challenges. Furthermore, it was consistently observed that calcareous samples exhibited elevated UCS, and shear strength values compared to their silica counterparts. This discrepancy underscores the inherent differences in mechanical behavior between these two types of sand, highlighting the need for tailored stabilization approaches. Moreover, the investigation delved into the failure patterns and microstructural changes within the stabilized samples, employing Scanning Electron Microscopy (SEM) for detailed analysis. This microscopic examination offered valuable insights into the efficacy of the stabilizing agents and their impact on the soil's mechanical properties. For instance, SEM imaging revealed significant bonding in fiber-reinforced samples, indicating enhanced load transfer mechanisms. Similarly, the presence of clusters of nano-silica particles adhering to sand particles showcased an improved cohesion within the stabilized soil. PU-stabilized samples, on the other hand, exhibited a cohesive layer enveloping sand particle, thereby enhancing interparticle connectivity and overall stability. The superior performance of PU over nano-silica was underscored by its ability to create a more cohesive matrix and foster stronger interparticle bonds, as evidenced by the SEM analysis. In conclusion, this study sheds light on the potential of innovative stabilization materials such as PU foam, nano-silica, and basalt fiber in bolstering the mechanical properties of soil. The findings not only offer valuable insights into the efficacy of these additives but also pave the way for the development of tailored soil stabilization techniques geared towards enhancing infrastructure resilience and sustainability.
Article Type:
Original Research |
Subject:
Geotechnic Received: 2024/03/13 | Accepted: 2024/08/31