Analysis of the structural and environmental impacts of hydrophilic ZSM-5 molecular sieve on loess

Abstract

Foundation treatment is an essential pre-work for the building construction. Recently, a lot of attention has been paid to loess stabilizers, due to the wide distribution of loess deposits. In this work, ZSM-5 molecular sieve is firstly applied as a loess stabilizer, with the aim of investigating its stabilizing and environmental performance. The unconfined compression strength (USC) and shear strength envelope of hydrophilic ZSM-5 molecular sieve stabilized loess (ZSL) samples with different ZSM-5 molecular sieve contents are measured, showing that the strength of ZSL samples is significantly enhanced. The reasons for the changes in mechanical properties are explained by a microstructural interpretation considering different aspects of ZSL sample microstructure, including cementation strength, mineral analysis, morphological, pore, and elemental composition. Based on the experimental evidence of the changes induced by stabilization on microstructure and mechanical properties, two categories are then defined in terms of ZMS-5 content, and a schematic diagram of the stabilization mechanism is provided. The environmental impacts of the loess stabilization process achieving similar shear strength with ZSM-5 molecular sieve, lime, and cement are figured out and compared by life cycle assessment. The research proves that the stabilization method with ZSM-5 molecular sieve is characterized a better environmental performance in terms of greenhouse gas emission. By analyzing the contribution of every material used in the production of ZSM-5 molecular sieve, a more environmentally friendly and effective production strategy has been finally proposed, which can promote the diffusion of ZSM-5 molecular sieve in the market of loess foundation stabilization.