Chemical Treatment of a Highly Expansive Clay Using a Liquid Ionic Soil Stabilizer
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ORIGINAL PAPER
Chemical Treatment of a Highly Expansive Clay Using a Liquid Ionic Soil Stabilizer Sandesh Gautam . Laureano R. Hoyos . Shi He . Srinivas Prabakar . Xinbao Yu
Received: 5 October 2019 / Accepted: 2 May 2020 Springer Nature Switzerland AG 2020
Abstract Expansive soils for residential projects are often treated with liquid ionic soil stabilizer (LISS) using deep pressurized injection method. Liquid ionic soil stabilizers have a long history of application in practice. However, there is limited knowledge and experimental evidence of their stabilization mechanism and effectiveness. This paper summarizes the research that investigated the effects of liquid ionic stabilizers on key engineering properties of a highly expansive clay from Carrollton, Texas, through comprehensive physical and mechanical testing and microscopic observation of untreated and treated soils. Test results before and after treatment were analyzed for two different treatment ratios: 1:300 and 1:150, showing a 53% swell reduction for treated soil compacted at the optimum moisture content (OMC) for treated soil, and 25% swell reduction for treated soil compacted at the OMC for the untreated soil. There was no significant improvement in unconfined compressive strength; noticeable improvement in stiffness was observed. The microscopic analysis showed a marked change in morphology and quantitative element composition, thus suggesting the occurrence of a reasonable degree of stabilization.
S. Gautam L. R. Hoyos S. He S. Prabakar X. Yu (&) Department of Civil Engineering, University of Texas at Arlington, Arlington, USA e-mail: [email protected]
Keywords Liquid ionic soil stabilizer Expansive soil Standard compaction Swell Clay minerals
1 Introduction Pavement distress and foundation failure are common in expansive soils and result in significant expenditures for repair and maintenance. The United States suffers billions of dollars of economic loss each year due to expansive soil problems. Chemical stabilization of these soils is usually achieved by using traditional stabilizers such as lime, cement, and fly ash. The underlying stabilization mechanisms are well known, and the standards for practice are properly documented for these stabilizers. However, they are expensive: the production of 1-ton ordinary Portland cement requires up to 150 kWh of energy, which is almost 40% of the total production cost (Khadka 2017). In addition, they are calcium-based; hence their use in sulfate-rich soils leads to excessive swelling and heaving (Hunter 1998). As the calcium present in the stabilizer reacts with sulfate and alumina in the soil, it forms a series of calcium–aluminum–sulfate hydrates; and the formed minerals, namely ettringite and thaumasite, cause a substantial increase in volume. Non-traditional stabilizers are a potentially feasible alternative to traditional calcium-based stabilizers. They are classified into several categories: ionic,
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Geotech Geol Eng
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