Experimental evaluation of strength and durability characteristics of geopolymer stabilised soft soil for deep mixing ap
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TECHNICAL PAPER
Experimental evaluation of strength and durability characteristics of geopolymer stabilised soft soil for deep mixing applications V. Bhavita Chowdary1 · V. Ramanamurty1 · Rakesh J. Pillai2 Received: 25 June 2020 / Accepted: 10 November 2020 © Springer Nature Switzerland AG 2020
Abstract Vast deposits of high water content soft clays pose severe problems and are not suitable for construction of engineering projects due to their inadequate bearing capacity and inherent large swelling and shrinkage ability. Deep soil mixing (DSM) is one of the widely accepted methods for improving soft soil properties like increase in bearing capacity and reduction in settlement that are of utmost importance for the construction of any structure. In this study, ground granulated blast furnace slag (GGBS)-based geopolymer was used to investigate its efficiency as a sustainable replacement to cement for DSM applications, thereby reducing the carbon footprint. A total of 27 GGBS-geopolymer mixes and 9 cement-treated reference mixes were cast and tested for strength and durability characteristics. The variables of the study include binder content (10, 20, and 30%), activator/binder ratio (0.5, 0.75, and 1.0), and initial soil moisture content (0.75wL, wL, 1.25wL). Different tests were conducted to explore the properties of stabilised clays, such as unconfined compressive strength, flexural strength, and durability against wetting drying cycles. To meet the requirements of DSM application, binder dosage greater than 10% and A/B ratio greater than 0.5 were recommended. With an increase in initial soil moisture content, the strength of the treated specimens under unconfined compression and flexure reduced and thus increased binder dosage helps to meet the DSM requirements for high water content soils. From the present study, it can be concluded that using slag-geopolymer binder for stabilising soft soil is an effective and sustainable alternative to cement in DSM applications. Keywords Deep soil mixing · Soft clay · Geopolymer · Strength · Durability
Introduction When it becomes indispensable to construct structures over soft clay beds which possess minimal to almost zero shear strength, it becomes essential to stabilise such soils with the known methods of physical and/or chemical stabilisation so that the treated ground provides a stable medium for transfer of loads. If the soft soil deposits extend to greater depths, it becomes necessary to opt for deep stabilisation techniques such as stone columns, grouting, electro osmosis, preloading with vertical drains, and so on, in order to make the ground feasible for construction purposes [1]. One of such * V. Bhavita Chowdary [email protected] 1
Department of Civil Engineering, National Institute of Technology Warangal, Warangal, Telangana 506004, India
Department of Civil Engineering, Indian Institute of Technology Palakkad, Palakkad, Kerala 678557, India
2
techniques is the deep soil mixing (DSM) method, which is a novel technique being used worldwide in
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