Intermittent swelling and shrinkage of a highly expansive soil treated with polyacrylamide
- Soltani, Amin, Deng, An, Taheri, Abbas, O'Kelly, Brendan
- Authors: Soltani, Amin , Deng, An , Taheri, Abbas , O'Kelly, Brendan
- Date: 2022
- Type: Text , Journal article
- Relation: Journal of Rock Mechanics and Geotechnical Engineering Vol. 14, no. 1 (2022), p. 252-261
- Full Text:
- Reviewed:
- Description: This laboratory study examines the potential use of an anionic polyacrylamide (PAM)-based material as an environmentally sustainable additive for the stabilization of an expansive soil from South Australia. The experimental program consisted of consistency limits, sediment volume, compaction and oedometer cyclic swell–shrink tests, performed using distilled water and four different PAM-to-water solutions of PD = 0.1 g/L, 0.2 g/L, 0.4 g/L and 0.6 g/L as the mixing liquids. Overall, the relative swelling and shrinkage strains were found to decrease with increasing number of applied swell–shrink cycles, with an ‘elastic equilibrium’ condition achieved on the conclusion of four cycles. The propensity for swelling/shrinkage potential reduction (for any given cycle) was found to be in favor of increasing the PAM dosage up to PD = 0.2 g/L, beyond which the excess PAM molecules self-associate as aggregates, thereby functioning as a lubricant instead of a flocculant; this critical dosage was termed ‘maximum flocculation dosage’ (MFD). The MFD assertion was discussed and validated using the consistency limits and sediment volume properties, both exhibiting only marginal variations beyond the identified MFD of PD = 0.2 g/L. The accumulated axial strain progressively transitioned from ‘expansive’ for the unamended soil to an ideal ‘neutral’ state at the MFD, while higher dosages demonstrated undesirable ‘contractive’ states. © 2022 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences
- Authors: Soltani, Amin , Deng, An , Taheri, Abbas , O'Kelly, Brendan
- Date: 2022
- Type: Text , Journal article
- Relation: Journal of Rock Mechanics and Geotechnical Engineering Vol. 14, no. 1 (2022), p. 252-261
- Full Text:
- Reviewed:
- Description: This laboratory study examines the potential use of an anionic polyacrylamide (PAM)-based material as an environmentally sustainable additive for the stabilization of an expansive soil from South Australia. The experimental program consisted of consistency limits, sediment volume, compaction and oedometer cyclic swell–shrink tests, performed using distilled water and four different PAM-to-water solutions of PD = 0.1 g/L, 0.2 g/L, 0.4 g/L and 0.6 g/L as the mixing liquids. Overall, the relative swelling and shrinkage strains were found to decrease with increasing number of applied swell–shrink cycles, with an ‘elastic equilibrium’ condition achieved on the conclusion of four cycles. The propensity for swelling/shrinkage potential reduction (for any given cycle) was found to be in favor of increasing the PAM dosage up to PD = 0.2 g/L, beyond which the excess PAM molecules self-associate as aggregates, thereby functioning as a lubricant instead of a flocculant; this critical dosage was termed ‘maximum flocculation dosage’ (MFD). The MFD assertion was discussed and validated using the consistency limits and sediment volume properties, both exhibiting only marginal variations beyond the identified MFD of PD = 0.2 g/L. The accumulated axial strain progressively transitioned from ‘expansive’ for the unamended soil to an ideal ‘neutral’ state at the MFD, while higher dosages demonstrated undesirable ‘contractive’ states. © 2022 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences
Stabilization of a highly expansive soil using waste-tire-derived aggregates and lime treatment
- Soltani, Amin, Taheri, Abbas, Deng, An, O'Kelly, Brendan
- Authors: Soltani, Amin , Taheri, Abbas , Deng, An , O'Kelly, Brendan
- Date: 2022
- Type: Text , Journal article
- Relation: Case Studies in Construction Materials Vol. 16, no. (2022), p.
- Full Text:
- Reviewed:
- Description: This study investigates the combined efficacy of waste-tire-derived aggregate (TDA) materials and hydrated lime on the compactability, compressive strength and swelling potential of a highly expansive soil from South Australia. A total of 21 mix-designs, covering a comprehensive range of soil–TDA–lime combinations, were examined through standard Proctor compaction, unconfined compressive strength (UCS) and oedometer swell tests. The mobilized UCS exhibited a ‘rise–fall’ behavior, peaking at 5% TDA content and subsequently decreasing (monotonically) for higher inclusions of TDA. Increasing the TDA mean particle size (from 1.67 to 3.34 mm) also contributed positively to the UCS development. Addition of TDA to the soil/soil–lime-blends produced notable reductions in the swelling potential; the reduction was primarily governed by higher TDA contents, and, to a lesser degree, for larger TDA mean particle sizes. However, the role of TDA particle size in reducing swelling was found to be more significant than that of enhancing the UCS. As expected, lime treatment of the soil–TDA blends provided major further improvements to the UCS and swelling potential reduction; the achieved UCS improvements being positively proportional to the lime content and curing time. In view of the experimental results, soil–lime blends containing TDA to soil–lime mass ratios of up to 10% (preferably employing coarse-sand-sized equivalent TDA) can be deemed as suitable choices (capable of adequately mitigating the swelling potential, while simultaneously enhancing the UCS). © 2022 The Authors
- Authors: Soltani, Amin , Taheri, Abbas , Deng, An , O'Kelly, Brendan
- Date: 2022
- Type: Text , Journal article
- Relation: Case Studies in Construction Materials Vol. 16, no. (2022), p.
- Full Text:
- Reviewed:
- Description: This study investigates the combined efficacy of waste-tire-derived aggregate (TDA) materials and hydrated lime on the compactability, compressive strength and swelling potential of a highly expansive soil from South Australia. A total of 21 mix-designs, covering a comprehensive range of soil–TDA–lime combinations, were examined through standard Proctor compaction, unconfined compressive strength (UCS) and oedometer swell tests. The mobilized UCS exhibited a ‘rise–fall’ behavior, peaking at 5% TDA content and subsequently decreasing (monotonically) for higher inclusions of TDA. Increasing the TDA mean particle size (from 1.67 to 3.34 mm) also contributed positively to the UCS development. Addition of TDA to the soil/soil–lime-blends produced notable reductions in the swelling potential; the reduction was primarily governed by higher TDA contents, and, to a lesser degree, for larger TDA mean particle sizes. However, the role of TDA particle size in reducing swelling was found to be more significant than that of enhancing the UCS. As expected, lime treatment of the soil–TDA blends provided major further improvements to the UCS and swelling potential reduction; the achieved UCS improvements being positively proportional to the lime content and curing time. In view of the experimental results, soil–lime blends containing TDA to soil–lime mass ratios of up to 10% (preferably employing coarse-sand-sized equivalent TDA) can be deemed as suitable choices (capable of adequately mitigating the swelling potential, while simultaneously enhancing the UCS). © 2022 The Authors
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+
- 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+
A borehole stability study by newly designed laboratory tests on thick-walled hollow cylinders
- Hashemi, Sam, Melkoumian, Nouné, Taheri, Abbas
- Authors: Hashemi, Sam , Melkoumian, Nouné , Taheri, Abbas
- Date: 2015
- Type: Text , Journal article
- Relation: Journal of Rock Mechanics and Geotechnical Engineering Vol. 7, no. 5 (2015), p. 519-531
- Full Text:
- Reviewed:
- Description: At several mineral exploration drilling sites in Australia, weakly consolidated formations mainly consist of sand particles that are poorly bonded by cementing agents such as clay, iron oxide cement or calcite. These formations are being encountered when drilling boreholes to the depth of up to 200 m. To study the behaviour of these materials, thick-walled hollow cylinder (TWHC) and solid cylindrical synthetic specimens were designed and prepared by adding Portland cement and water to sand grains. The effects of different parameters such as water and cement contents, grain size distribution and mixture curing time on the characteristics of the samples were studied to identify the mixture closely resembling the formation at the drilling site. The Hoek triaxial cell was modified to allow the visual monitoring of grain debonding and borehole breakout processes during the laboratory tests. The results showed the significance of real-time visual monitoring in determining the initiation of the borehole breakout. The size-scale effect study on TWHC specimens revealed that with the increasing borehole size, the ductility of the specimen decreases, however, the axial and lateral stiffnesses of the TWHC specimen remain unchanged. Under different confining pressures the lateral strain at the initiation point of borehole breakout is considerably lower in a larger size borehole (20 mm) compared to that in a smaller one (10 mm). Also, it was observed that the level of peak strength increment in TWHC specimens decreases with the increasing confining pressure. © 2015 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences.
- Authors: Hashemi, Sam , Melkoumian, Nouné , Taheri, Abbas
- Date: 2015
- Type: Text , Journal article
- Relation: Journal of Rock Mechanics and Geotechnical Engineering Vol. 7, no. 5 (2015), p. 519-531
- Full Text:
- Reviewed:
- Description: At several mineral exploration drilling sites in Australia, weakly consolidated formations mainly consist of sand particles that are poorly bonded by cementing agents such as clay, iron oxide cement or calcite. These formations are being encountered when drilling boreholes to the depth of up to 200 m. To study the behaviour of these materials, thick-walled hollow cylinder (TWHC) and solid cylindrical synthetic specimens were designed and prepared by adding Portland cement and water to sand grains. The effects of different parameters such as water and cement contents, grain size distribution and mixture curing time on the characteristics of the samples were studied to identify the mixture closely resembling the formation at the drilling site. The Hoek triaxial cell was modified to allow the visual monitoring of grain debonding and borehole breakout processes during the laboratory tests. The results showed the significance of real-time visual monitoring in determining the initiation of the borehole breakout. The size-scale effect study on TWHC specimens revealed that with the increasing borehole size, the ductility of the specimen decreases, however, the axial and lateral stiffnesses of the TWHC specimen remain unchanged. Under different confining pressures the lateral strain at the initiation point of borehole breakout is considerably lower in a larger size borehole (20 mm) compared to that in a smaller one (10 mm). Also, it was observed that the level of peak strength increment in TWHC specimens decreases with the increasing confining pressure. © 2015 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences.
- «
- ‹
- 1
- ›
- »