Kaolin Clay Reinforced with a Granular Column Containing Crushed Waste Glass or Traditional Construction Sands

Abstract

Installation of granular columns is a cost-effective and versatile in situ technique to improve the shear strength, settlement, and drainage behaviour of weak soils. It involves backfilling vertical boreholes in the ground with granular materials stiffer than the native soil, such as stone or compacted sand.However, the massive use and overexploitation of sand and natural aggregates have depleted their reserves in recent decades, causing damage to the environment, creating sand shortages and skyrocketing their price. Hence, it is essential to develop a sustainable alternative to natural aggregates to construct granular columns. The ever-increasing stockpiles of waste glass could be a potential replacement for natural sand in several geotechnical construction applications, noting that both materials have a similar chemical composition. Using crushed waste glass (CWG) as an alternative to traditional natural and manufactured (quarried) sands in granular columns could offer a multipronged benefit by recycling non-biodegradable waste (glass) and by conserving a depleting natural resource (sand). Using a large direct shear (LDS) machine, this study investigated the shear strength behaviour of kaolin (to represent a typical weak soil) reinforced with a central granular column. Three different materials were separately used to backfill the column, including natural sand (NS), manufactured sand (MS) and CWG. The results revealed that the geocomposites containing the CWG column have the highest peak friction angle and relatively greater shear strength under high normal stresses, favouring the potential use of CWG as a green alternative to traditional sands in backfilling granular columns, ultimately supporting resource conservation, waste recycling and the paradigm shift towards a circular economy.

Shear Strength of Soft Clay Reinforced With Acrylonitrile Butadiene Styrene (Abs) Column

“…The average specific gravity of the kaolin obtained from the specific gravity test using a pycnometer is 2.63. This number is consistent with [31], which indicates that the normal range of soil-specific gravity values is between 2.40 and 2.78. However, earlier research indicates that the basic gravity of kaolinite clay is 2.6 [32].…”

“…Pandey [30] and Kazmi [31] discovered that the area replacement ratio and the column-over-column diameter ratio increased in sand-column studies. The increase in the area replacement ratio enhanced the shear strength of soft clay.…”

Shear Strength and Consolidation Behaviour of Kaolin Clay Reinforced with a Granular Column Backfilled with Crushed Waste Glass

“…Traditionally, natural aggregates have been used to create granular columns (Chidiroglou et al 2009). However, given the increasing volumes of waste and growing scarcity of virgin aggregates (sand and stone), waste materials could provide a sustainable alternative to traditional construction aggregates (Kazmi et al 2022;van Genuchten 2023;Jefferson et al 2010). The world faces a shortage of natural and quarried (manufactured) sand (Bendixen et al 2019).…”

“…Fig.9Peak shear strength envelopes of the kaolin only specimens and the geocomposites (adapted fromKazmi et al 2022) …”