Swell–Shrink–Consolidation Behavior of Rubber–Reinforced Expansive Soils

Abstract

This study examines the effects of two types of recycled tire rubber of fine and coarse categories on the swell-shrink-consolidation behavior of a highly expansive soil mixture. Each of the two rubber choices were incorporated into the soil at four different content levels (i.e., rubber to dry soil mass ratio) of 5, 10, 20, and 30 %. The experimental program consisted of consistency limits, compaction, swellconsolidation, swell-shrink, and unconfined compression tests. Improvement in the swell-shrink-consolidation capacity was in favor of higher rubber contents; however, when excessively included, it raised strength concerns. The swellshrink-consolidation properties were also rubber size-dependent, meaning that the rubber of coarser sizes often outperformed finer rubber. In terms of strength, however, the two rubber types promoted similar results with marginal differences. The results of the unconfined compression tests were cross checked with the swell-shrink-consolidation properties to arrive at the optimum stabilization scenarios. A maximum rubber inclusion of 10 %, preferably the rubber of coarser category, proved to satisfy the stabilization objectives (i.e., decrease in the swell-shrink-consolidation capacity as well as maintain or improve the strength) and thus was deemed as the optimum choice. Where context changes and the strength and stiffness are not a primary concern, higher rubber inclusions of up to 20 % may also be considered acceptable.

Experimental Investigation of Consolidation Properties of Nano-Bentonite Mixed Clayey Soil

“…In general, a variety of reinforcing or treatment materials can be added to foundation soils to modify or improve their strength and deformation properties [5][6][7][8][9]. Such materials are divided into three types: inorganic binders, ionic soil stabilizing agents, and composite curing agents.…”

Consistency limits and compaction characteristics of clay soils containing rubber waste

“…swell-shrink capacity), which can facilitate the production and placement of sustainable earth fills such as road and railway embankments (e.g. Cabalar et al, 2014;Cetin et al, 2006;Özkul and Baykal, 2007;Perez et al, 2017;Signes et al, 2016;Soltani et al, 2018bSoltani et al, , 2018cSrivastava et al, 2014;Trouzine et al, 2012;Wang et al, 2018;Tiwari, 2017a, 2017b). When placed in a flowable condition, the rubber-soil blend outperforms conventional soil backfills by enabling the placement of particles into any irregular or inaccessible space without significant compaction efforts (ACI R229 (ACI, 2013)).…”

Strength Characteristics of Clay-Rubber Waste Mixtures in UU Triaxial Tests

“…The majority of research carried out on waste is directed primarily towards checking their influence on a change of the optimum moisture content in soils [17,18], on the mechanical behavior of soils [19][20][21][22][23], on the reduction of Atterberg's limits and plasticity index of fine-grained soils [21,[24][25][26], and on the reduction of natural soils swelling [16,[27][28][29][30]. If the first two groups of issues apply to all soils, then the next two are strictly related to cohesive (frequently expansive) soils.…”

“…All those discrepancies observed in the soil-rubber mixtures behavior result from three basic reasons: soil type, type of rubber waste used (size/shape; e.g., [28,29,36,37]), and its percentage (weight or volume) content. According to European Committee for Standardization Workshop Agreement CEN CWA 14243:2002 [38], the following types of rubber waste are distinguished: powder (P) <1 mm and fine powder (F) <0.5 mm, granulate (G) 1-10 mm, chips (C) 10-50 mm, shreds (S) 50-300 mm, tire cuts (X) >300 mm, and buffings (B) 1-40 mm.…”