Showing items 1 - 3 of 3

Your selections:

Improved shear strength performance of compacted rubberized clays treated with sodium alginate biopolymer

- Soltani, Amin, Raeesi, Ramin, Taheri, Abbas, Deng, An, Mirzababaei, Mehdi

  • Authors: Soltani, Amin , Raeesi, Ramin , Taheri, Abbas , Deng, An , Mirzababaei, Mehdi
  • Date: 2021
  • Type: Text , Journal article
  • Relation: Polymers Vol. 13, no. 5 (2021), p. 1-21
  • Full Text:
  • Reviewed:
  • Description: This study examines the potential use of sodium alginate (SA) biopolymer as an environmentally sustainable agent for the stabilization of rubberized soil blends prepared using a high plasticity clay soil and tire-derived ground rubber (GR). The experimental program consisted of uniaxial compression and scanning electron microscopy (SEM) tests; the former was performed on three soil–GR blends (with GR-to-soil mass ratios of 0%, 5% and 10%) compacted (and cured for 1, 4, 7 and 14 d) employing distilled water and three SA solutions—prepared at SA-to-water (mass-tovolume) dosage ratios of 5, 10 and 15 g/L—as the compaction liquid. For any given GR content, the greater the SA dosage and/or the longer the curing duration, the higher the uniaxial compressive strength (UCS), with only minor added benefits beyond seven days of curing. This behaviour was attributed to the formation and propagation of so-called “cationic bridges” (developed as a result of a “Ca2+/Mg2+

Mechanical performance of tire-derived aggregate permeable pavements under live traffic loads

- Raeesi, Ramin, Soltani, Amin, King, Russell, Disfani, Mahdi

  • Authors: Raeesi, Ramin , Soltani, Amin , King, Russell , Disfani, Mahdi
  • Date: 2022
  • Type: Text , Conference paper
  • Relation: 4th International Conference on Transportation Geotechnics, ICTG 2021 Vol. 164, p. 515-528
  • Full Text: false
  • Reviewed:
  • Description: Traditional pavements in urban areas are mainly rigid, impervious surfaces, resulting in augmented surface run off during rainfalls, thereby leading to flash-flooding and pollution of waterways. In comparison, permeable pavements permit percolation of water through surface layers, thus alleviating harmful environmental impacts. This study presents the authors’ recent experience in the development of an instrumented large-scale permeable pavement trial site—constructed using a combination of crushed rock (CR) and tire-derived aggregate (TDA), bonded by a polyurethane (PU) binder—located at a car park in South Australia. An area of approximately 400 m2 was paved using different TDA-based mix designs—different CR sizes, colors, and shapes, and different PU contents. Moreover, preliminary field performance monitoring results—including surface deflection measurements by the light weight deflectometer test, and strain measurements using optic fiber and strain gauge sensing techniques—are outlined and discussed in detail. The strength and stiffness of the TDA-based blend was found to be dependent on the TDA content, TDA-to-CR size ratio, CR shape, and PU content. The greater the angularity of the CR particles, the more effective the interlocking of the TDA and CR components, and thus the higher the developed strength and stiffness. The amount of strain generated in the permeable surface layer and at its interface with the lower screening layer were both found to decrease with a decrease in TDA content. Preliminary field observations indicate that the TDA-based system can indeed be a viable (and sustainable) solution to effectively mitigate flash-flooding while sustaining low–medium traffic loads. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG.

Compressibility behavior of soft-rigid granular mixtures bound with polyurethane binder

- Raeesi, Ramin, Soltani, Armin, Disfani, Mahdi

  • Authors: Raeesi, Ramin , Soltani, Armin , Disfani, Mahdi
  • Date: 2022
  • Type: Text , Journal article
  • Relation: International Journal of Geomechanics Vol. 22, no. 1 (2022), p.
  • Full Text: false
  • Reviewed:
  • Description: Mixtures of recycled tires and granular material have been used for a variety of applications in geotechnical engineering over the years. The characteristics and mechanical properties of sand-rubber mixtures as unbound soft-rigid mixtures have been extensively studied over the years. Research on bound soft-rigid mixtures, however, has been mainly focused on using a brittle binding agent, for example, Portland cement. A very limited number of studies over the last years have examined the behavior of soft-rigid mixtures bound with a nonbrittle binder. This study aims to provide a better understanding of the deformation mechanism of the soft-rigid mixtures bound with a polyurethane binder. Sixteen one-dimensional compression tests were conducted on bound and unbound samples to study the impact of the binding agent on the behavior of the soft-rigid mixture. In addition, computed tomography scan images of samples were used to visualize the deformation mechanism. A multiphased behavior, as opposed to single-phased behavior for unbound mixtures, was observed and each phase was explained in detail. The observed multiphased behavior is divided into up to four phases, that is, initial compression, normal compression, bond degradation, and secondary compression, with boundaries defined based on constrained modulus curve. © 2021 American Society of Civil Engineers.
  • 1