Experimental study on strength characteristics and internal mineral changes of Lime-stabilized loess under High-Temperature. (10th October 2022)

• Record Type: Journal Article
• Authors: Bao, Weixing; Wang, Haibo; Lai, Hongpeng; Chen, Rui
• Is Part Of: Construction & building materials. Volume 351(2022)
• Publication Date: 2022-10-10
• Subjects: Lime-stabilized loess -- High temperature treatment -- Unconfined compressive strength -- Shear strength -- X-ray diffraction -- Thermal analytical techniques; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2022.128945
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: Effect of lime treatment on compression and shear strength of loess were studied. Tests were carried out at a wide temperature range (30 ∼ 300 °C) and 5 lime contents. Treatment with lime improved the strength of loess at high-temperatures. Multiple methods XRD, TGA, DSC reveal the mechanisms of the lime-loess reactions. Abstract: In this study, lime-stabilized loess with five lime contents (0 %, 3.5 %, 7 %, 10.5 %, and 14 %) treated at four temperature levels (30 °C, 100 °C, 200 °C, and 300 °C) were tested for 48 h in a series of laboratory experiments to investigate the mechanical strength characteristics and internal mineral changes of lime-stabilized loess under high temperature. The unconfined compressive strength (UCS) tests and shear box test results show that the compressive and shear strengths of lime-stabilized loess are larger than those of plain loess, not only at room temperature but also at high temperatures. Under the same lime content, the mechanical strength of each sample was greatly improved after high-temperature treatment. As the heat-treatment temperature increased within the test temperature range, the compressive and shear strengths gradually improved. These mechanical strength test results prove that adopting lime-stabilized loess as the building material for structures vulnerable to high temperatures is feasible. When compressive and shear strengths were selected as the evaluation criteria for determining the lime content, the optimal lime content in this study was 7 %. X-ray diffraction and thermal analysis test results revealed that the strength enhancement of lime-stabilized loess is mainly derived from the lime slaking reaction, pozzolanic reaction, and crystallization reaction. High-temperature treatments can promote the reaction rates of these processes.