Sustainable improvement in engineering behavior of Siwalik Clay using industrial waste glass powder as additive

Abstract

The focus of the present study is to improve the engineering behavior of Clays belonging to Upper Siwalik Formation and located in the sub-tropical zone with average annual rainfall of 297 mm. The presence of shear zones and random fissures in these over consolidated and slicken sided clays pose serviceability problems like differential settlement, pavement defects and excessive erosion resulting into the massive loss of property. Suitability assessment of industrial waste glass powder (IWGP) to address the issue could be twofold beneficial: potential solution of the problem; and economical utilization of waste leading to clean environment. The IWGP ranging from 5% to 20% to the air-dried mass of base soil was used to evaluate its impact on various properties. Laboratory testing including grain size distribution, Atterberg limits, compaction characteristics, unconfined compressive strength (UCS), California bearing ratio (CBR) for un-soaked and soaked conditions and swell potential of the control and clay samples was conducted. As no chemical reaction (hydration) was expected between soil and IWGP, curing of samples was not considered. The test results showed that addition of 20% IWGP showed maximum improvement in the UCS (110%), un-soaked (67%) and soaked (300%) CBR values. On the other hand, 26% reduction in swelling strain at 1kPa effective vertical stresses was also observed with this combination. The capital cost analysis for one-kilometer dual carriageway, for all combinations of soil and IWGP, showed that 15% dosage was the optimum quantity providing adequate strength enhancement (54.5%) with substantial reduction of 19% in capital cost. Besides, it poses very low environmental risk for nearby aqueous media. Consequently, IWGP has been assessed as a sustainable modifier for improvement of Siwalik Clay leading to potential solution for serviceability problems.