Consistency limits and compaction characteristics of clay soils containing rubber waste

Abstract

The aim of the study reported in this paper was to develop practical correlative models capable of predicting the compaction characteristics of clay soils blended with rubber from waste vehicle tyres. Four different clay soils, ranging from intermediate to high plasticity, were adopted for the test programme and each was blended with four different percentages of ground rubber waste. The test programme consisted of cone penetration (consistency limits) and standard Proctor compaction tests. As a result of ground rubber inclusion, the consistency limits and compaction characteristics all exhibited a linear decreasing trend with increase in rubber content. The rate of decrease, however, was greater for the high-plasticity clays. Simple correlative models, linking the compaction characteristics to the consistency limits, were suggested and validated by statistical techniques. The proposed models provide a practical procedure towards predicting the compaction characteristics of ground rubber-clay blends without the hurdles of conducting laboratory compaction tests, and thus can be implemented in practice for preliminary assessments.

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

“…It is worth drawing attention to the fact that results of presented tests can be compared with only one paper, in which authors also were carrying out UU triaxial tests on specimens of kaolinite clay and kaolinite clay-crumb rubber mixtures [31]. In both cases, for rubber waste there are similar values of angle of internal friction −27.5° for powder and 28.7° for granulate (in this study) and 19°-26° for crumb [31] as well as cohesion-1.7 kPa for powder and 6 kPa for granulate (in this study) and 1-5 kPa for crumb [24]. Tajdini et al [31], in mixtures with kaolin, were using crumb-type waste in two size ranges: 2-5 mm (marked by symbol G30) and 1-3 mm (marked by symbol G80) and with three weight contents: 5%, 10%, and 15%.…”

“…In the case of powder, the relationship was inverse: shear stresses were higher for a greater powder content (P-25). The report from Tajdini et al's [24] study did not comprise the information on changes of failure shear stress in terms of G30 or G80 content. Obviously, although the conditions of this study were close to those of Tajdini et al [24], they were not identical.…”

“…The report from Tajdini et al's [24] study did not comprise the information on changes of failure shear stress in terms of G30 or G80 content. Obviously, although the conditions of this study were close to those of Tajdini et al [24], they were not identical. Basic differences included: another soil type, no saturation with water before presented tests, another type of rubber waste, higher decrease of cohesion in (RCR) mixtures, and perhaps a different mineralogical composition of soils (Tajdini et al [31] did not provide the mineralogical composition of kaolinite clay).…”

“…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.…”

Use of Geogrids and Recycled Rubber in Railroad Infrastructure for Enhanced Performance

“…These impact forces can likewise be generated at transition zones involving abrupt variations of vertical track stiffness, such as at the approaches to tunnels, bridge or viaduct and level crossings, or where there is a sudden change from conventional ballast to slab track intensifying ballast breakage and adversely affecting track stability [11][12][13][14][15]. One potential method of enhancing the substructure capacity to withstand the large cyclic and impact loads induced by fast-moving heavy-haul trains is to improve the performance of the ballast layer using plastic (e.g., geogrids) and rubber inclusions (e.g., rubber mat, tire cell, and rubber crumbs) [2,[11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30].…”