Effect of Polypropylene Fiber Reinforcement on the Consolidation, Swell and Shrinkage Behavior of Lime Blended Expansive Soil

In this article, synthetic fibers in the presence of lime stabilization are proposed as an alternative to overcome the issues related to shrink-swell distress in expansive soils. Two types of synthetic fibers, Fiber Cast® (FC) and Fiber Mesh® (FM), were studied by conducting one dimensional fixed ring Oedometer swell-consolidation and bar linear shrinkage tests. Three dosages (0.2, 0.4 and 0.6% percent by weight of soil) and two lengths of the fibers (6 and 12 mm) were evaluated with and without lime treatments. The results indicated that FC fibers had better swell restricting performance in the absence of lime treatment, while in the presence of lime both fibers had similar performance in reducing swelling. Shrinkage tests results showed that irrespective of dosage levels, both the fibers had pronounced effect in reducing the linear shrinkage strains up on lime treatment. Nonlinear best fit equations have been proposed to relate compression index (Cc) and recompression index (Cr) of expansive clay deposits with and without lime treatment to amount and dosage of FC and FM reinforcements. The proposed nonlinear fit provides a mean for recognizing, more efficiently, the patterns in the experimental data and predicting the compression indices, Cc and Cr reliably

Effect of Unit Weight on Porosity and Consolidation Characteristics of Expansive Clays

This study investigated the relationship between pore characteristics and unit weight of clayey soils. This relationship was particularly important in case of expansive soils, as the pore characteristics determine moisture flux boundaries, which in turn represent volume change behavior. Current research tried to evaluate the effect of compaction unit weight on the pore size and pore volume along with consolidation and swell characteristics on two expansive clays from semi-arid environment. The two selected clays represent soils with different degrees of expansion, particle size and mineralogy. Pore size characterization for these two soils was performed using Mercury Intrusion Porosimetry, while swell and consolidation characteristics were determined using a conventional oedometer test. Samples for both tests were compacted at different unit weights including, 100, 95, 90, 80, 75, and 70 % of maximum dry unit weight (MDUW) obtained from standard proctor. The compaction water content was kept constant for all unit weight levels. Both pore volume and pore size distribution was analyzed with varying unit weight characteristics and particle sizes. In addition, swell strains and compression indices were studied with varying unit weight of compacted specimens. It was observed that, in the case of samples compacted at 100 % MDUW, about 50 % of the pores were larger than 0.1 µm, and this value increased with reduction in unit weight. Current research is of practical importance, especially in the wake of microbial treatments for clayey soils where the passage of microbes depends on the pore size and more specifically pore throat size

Effect of Polypropylene Fibre Reinforcement on the Consolidation, Swell and Shrinkage Behaviour of Lime-Blended Expansive Soil

In this article, synthetic fibres in the presence of lime stabilisation are proposed as an alternative to overcome the issues related to shrink-swell distress in expansive soils. Two types of synthetic fibres, Fiber Cast® (FC) and Fiber Mesh® (FM), were studied by conducting one-dimensional fixed ring Oedometer swell-consolidation and bar linear shrinkage tests. Three dosages (0.2, 0.4 and 0.6% by weight of soil) and two lengths of the fibres (6 and 12 mm) were evaluated with and without lime treatments. The results indicated that FC fibres had better swell restricting performance in the absence of lime treatment, while in the presence of lime both fibres had similar performance in reducing swelling. Shrinkage tests results showed that irrespective of dosage levels, both the fibres had pronounced effect in reducing the linear shrinkage strains up on lime treatment. Non-linear best fit equations have been proposed to relate compression index (Cc ) and recompression index (Cr ) of expansive clay deposits with and without lime treatment to amount and dosage of FC and FM reinforcements. The proposed non-linear fit provides a mean for recognising, more efficiently, the patterns in the experimental data and predicting the compression indices, Cc and Cr reliably