Experimental study on the engineering characteristics of expansive soil improved conjointly using enzyme induced carbonate precipitation and eggshell powder

IF 3.3 2区工程技术 Q2 ENGINEERING, GEOLOGICAL

Soils and Foundations Pub Date : 2025-02-01 DOI:10.1016/j.sandf.2025.101567

Mudassir Mehmood , Yuancheng Guo , Yunlong Liu , Lei Wang , Wen Nie , Bantayehu Uba Uge , Sharafat Ali , Chen Xuanyu , Yingao Zhao

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Abstract

Enzyme induced carbonate precipitation (EICP) is gaining more and more recognition that can be utilized on-site to enhance the quality of the weak soil. In this experimental study, a novel approach that combines EICP and eggshell powder (ESP) to strengthen the engineering characteristics of natural expansive soil has been implemented. The engineering properties of expansive soil were examined using the environmentally friendly method EICP with an optimal 0.75 mol/L concentration and 14% ESP optimal content, with varying curing durations. ESP serves as a filler between particles and also a nucleation site to promote the precipitation of calcium carbonate. A thorough examination of the soil’s microstructure development after treatment was additionally executed through scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. The findings demonstrated that combining EICP and ESP decreases the swelling pressure about 25 times, compared with the individual treatment that yielded 5 and 1.5 times reduction for EICP and ESP, respectively. Additionally, the combined treatment led to an increase in the unconfined compressive strength, cohesion, internal friction angle, unsoaked CBR, and soaked CBR by 3, 1.6, 1.8, 8.0, and 9.5 times, respectively, indicating better enhancements than the individual treatments of EICP and ESP. Moreover, at the microstructural level, SEM imagery demonstrated a highly reinforced soil composite. The XRD analysis unveils distinct mineralogical changes, predominantly characterized by enhanced calcite formation and a refined microstructural composition. This study highlights the synergistic potential of combining EICP and ESP as stabilizing additives to enhance the engineering properties of expansive soil. Beyond soil enhancement, this innovative blend offers a sustainable solution by repurposing agrowaste. The mutual incorporation of EICP and ESP emerges as a promising strategy for advancing sustainable civil infrastructure development.

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来源期刊

Soils and Foundations 工程技术-地球科学综合

CiteScore

6.40

自引率

8.10%

发文量

审稿时长

5 months

期刊介绍： Soils and Foundations is one of the leading journals in the field of soil mechanics and geotechnical engineering. It is the official journal of the Japanese Geotechnical Society (JGS)., The journal publishes a variety of original research paper, technical reports, technical notes, as well as the state-of-the-art reports upon invitation by the Editor, in the fields of soil and rock mechanics, geotechnical engineering, and environmental geotechnics. Since the publication of Volume 1, No.1 issue in June 1960, Soils and Foundations will celebrate the 60th anniversary in the year of 2020. Soils and Foundations welcomes theoretical as well as practical work associated with the aforementioned field(s). Case studies that describe the original and interdisciplinary work applicable to geotechnical engineering are particularly encouraged. Discussions to each of the published articles are also welcomed in order to provide an avenue in which opinions of peers may be fed back or exchanged. In providing latest expertise on a specific topic, one issue out of six per year on average was allocated to include selected papers from the International Symposia which were held in Japan as well as overseas.