Strength, Swell, and Cost-Based Mix Optimization of Cement and Fly Ash-Treated Expansive Soils

会议论文
发表日期：

2024年

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A. M. S. N. Abeysinghe,
L. C. Kurukulasuriya,
M. C. M. Nasvi

摘要

Expansive soils pose significant challenges in construction projects due to their high susceptibility to volumetric changes caused by moisture fluctuations. Chemical stabilization of expansive soil has been successfully practiced for many years now to enhance the strength and swell characteristics of expansive soils, and cement and fly ash (FA) have been successfully used as stabilizing agents. However, very limited studies have been conducted focusing on the mix optimization of a given expansive soil using cement and FA by considering the strength, swell, and cost. Therefore, the aim of this research is to perform a mix optimization of cement and FA-stabilized expansive soil in terms of strength, swell, and cost analysis. Expansive soil samples were stabilized with 2–12% cement and 5–30% FA, and testing including index properties, unconfined compressive strength (UCS), and swell pressure was conducted. In addition, the ranking of the mixes was done by performing a utility analysis by employing Multi-Attribute Utility Theory (MAUT) incorporating strength, swell pressure, and cost/UCS as the key performance indicators. The findings revealed that the UCS of the cement-stabilized samples increases with the stabilizer content, whereas 15% FA was found to be the optimum FA content for high UCS for FA-stabilized samples. The UCS values of all the stabilized samples complied with the Austroads (Australia) and Institute for Construction Training and Development (ICTAD) (Sri Lanka) guidelines. The swell pressure values of cement-stabilized samples and FA-stabilized samples were reduced by 11.6–35.9% and 45.0–65.6% respectively depending on the binder content. The findings of the utility analysis revealed that all the FA-stabilized samples outperformed cement-stabilized samples, and 15% FA-stabilized mix is the most reliable mix whereas 4% cement-stabilized mix was found to be the least reliable mix in terms of strength, swell, and cost.