Experimental investigation on reuse of dredged soils improved using waste rubber tyre powder (WRTP) and cement as admixtures

Abstract

Dredged soils possessing low-bearing capacity and high compressibility were tested incorporating waste rubber tyre powder (WRTP) at varying percentages in increments of 1.5% up to 15% by dry weight of the soil and 2% cement. It was observed that maximum dry unit weight (MDUW) decreased to 11.75 and 12 kN/m3 for combinations of 15% WRTP and 15% WRTP + 2% cement respectively. Direct shear test (DST) parameter ‘c’ at 4.5% WRTP and 2% cement increased from 44 to 49 kN/m2 whereas angle of internal friction, ‘ϕ’ showed an increase up to 37°. The Unconfined compressive strength (UCS) of soil-WRTP-cement mixture enhanced from 110 kN/m2 in the untreated state to 596 kN/m2 at 28 days curing and 6% WRTP + 2% cement. Further, California bearing ratio (CBR) values increased up to an optimum addition of 6% WRTP + 2% cement, both in unsoaked (6 to 13%) and soaked condition (2 to 7%). Soil improvement using WRTP and cement can improve the strength and durability of road subgrades and embankments. WRTP in addition to cement can be used in locations with weak or problematic soils to improve load-bearing capacity and reduce settlement-related problems.