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Dr. Sumi Siddiqua
Faculty of Applied Science School of Engineering, The University of British Columbia, Vancouver BC V6T 1Z4, Canada

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Research Keywords & Expertise

0 Sustainable Infrastructure
0 Thermal-Hydraulic-Mechanical-Chemical Behaviour of Soil
0 Deep Underground Nuclear Waste Disposal Modeling
0 Contaminant Migration
0 Expansive, Collapsible and Organic Soil

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Original paper
Published: 14 August 2021 in Geotechnical and Geological Engineering
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Clean drinking water is a necessity and recycling stormwater and greywater has been more appealing in the recent decades to provide filtered water for drinking water and non-drinking water purposes. Biosand filters have been a popular filtering system of filtering potable water in developing countries, due to their simplicity in construction, reliability in operation and availability of constituent materials. The sand filtration system consists of diffuser rock, two sizes of gravel, and sand, which the container is constructed from concrete or plastic. Sand filtration system tend to struggle in removing specific chemicals such as nitrate and phosphate. Therefore, innovative materials can be added to the sand filtration system to increase the chances of chemical removal. Innovative materials such as biochar and bentonite clay were used to analyze their effectiveness in sand filtration system experiments. Biochar and bentonite clay have unique characteristics such as absorbing capacity and activated carbon, which remove suspended solids, chemicals, and toxins from contaminated water. Constant head permeability tests were used to simulate the sand filtration system in the lab. 15 tests were completed with different filter media arrangements, which incorporated two types of sand (coarse and fine), two sizes of gravel (small and large), biochar, and sodium bentonite clay. Contaminated water was created by simulating greywater by adding chemicals to reverse osmosis water. The pH, sulfate, chloride, phosphate and nitrate ion concentration removal were analyzed based on the contaminated water and filtered water. The hydraulic conductivity, filtration rate and pressure loss were also analyzed for each test. The tests that had the most effective result in terms of chemical ion removal, pH neutralization and filtration rate was the arrangement that included large and small gravel, fine and coarse sand, and biochar.

ACS Style

Derek Emslie; Sumi Siddiqua; Bryn Crawford; Wayne Teece. Biofilm Formation and Effectiveness of Biosand Filtration Systems with Typical and Innovative Filter Media. Geotechnical and Geological Engineering 2021, 1 -16.

AMA Style

Derek Emslie, Sumi Siddiqua, Bryn Crawford, Wayne Teece. Biofilm Formation and Effectiveness of Biosand Filtration Systems with Typical and Innovative Filter Media. Geotechnical and Geological Engineering. 2021; ():1-16.

Chicago/Turabian Style

Derek Emslie; Sumi Siddiqua; Bryn Crawford; Wayne Teece. 2021. "Biofilm Formation and Effectiveness of Biosand Filtration Systems with Typical and Innovative Filter Media." Geotechnical and Geological Engineering , no. : 1-16.

Journal article
Published: 22 July 2021 in Engineering Geology
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This paper presents findings of the effect of calcium bentonite (Ca-bentonite) and pulp mill fly ash (PFA) on the compressibility behavior, and microstructural evolution of organic soil. A natural soil consisting of 26% organic matter was collected from the wetlands in the Wabasca region, Northern Alberta, Canada. A various mix design was prepared for the laboratory tests with the addition of 5%, 8%, 10%, 12%, 15%, and 20% Ca-bentonite with constant 30% PFA. One-dimensional consolidation tests were carried out to evaluate compressibility behavior of the stabilized organic soil. In addition, fall cone tests were conducted to evaluate change in undrained shear streth of soil after stabilization. A series of scanning electron microscope (SEM) tests with energy dispersive X-ray (EDS) and X-ray diffraction (XRD) experiments were conducted to investigate the microstructural and chemical aspects of the organic soil treated with Ca-bentonite and PFA. The results showed that a mixture of 10% Ca-bentonite with 30% PFA was the optimum dosage for improving compressibility of organic soil regardless of the curing method. Microstructural and chemical analysis revealed that the mineralogical and morphological contents of the stabilized organic soil were affected due to the pozzolanic reaction. The results showed that Ca-bentonite and PFA were able to considerably improve the strength and compressibility of the selected organic soil.

ACS Style

Bigul Pokharel; Sumi Siddiqua. Effect of calcium bentonite clay and fly ash on the stabilization of organic soil from Alberta, Canada. Engineering Geology 2021, 293, 106291 .

AMA Style

Bigul Pokharel, Sumi Siddiqua. Effect of calcium bentonite clay and fly ash on the stabilization of organic soil from Alberta, Canada. Engineering Geology. 2021; 293 ():106291.

Chicago/Turabian Style

Bigul Pokharel; Sumi Siddiqua. 2021. "Effect of calcium bentonite clay and fly ash on the stabilization of organic soil from Alberta, Canada." Engineering Geology 293, no. : 106291.

Journal article
Published: 25 June 2021 in Construction and Building Materials
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Sustainable rammed earth (RE) material was formulated using pulp mill fly ash (PFA), an industrial waste product, as an alternative low carbon cementing material. The alkali-silicate activation of PFA in RE showed substantial strength improvement. However, combinations of calcium bentonite clay and raw PFA without activation imparted significantly better frost resilience properties. The recommended RE formulation with 5% PFA, 5% Portland cement and 15% bentonite showed 3.56 MPa compressive strength at 28 days curing and retained 92% strength after 12 freeze–thaw cycles. Further, the leachate analysis revealed that the cementitious reaction products immobilized toxic elements within the stabilized RE matrix.

ACS Style

Amin Ajabi Naeini; Sumi Siddiqua; Chinchu Cherian. A novel stabilized rammed earth using pulp mill fly ash as alternative low carbon cementing material. Construction and Building Materials 2021, 300, 124003 .

AMA Style

Amin Ajabi Naeini, Sumi Siddiqua, Chinchu Cherian. A novel stabilized rammed earth using pulp mill fly ash as alternative low carbon cementing material. Construction and Building Materials. 2021; 300 ():124003.

Chicago/Turabian Style

Amin Ajabi Naeini; Sumi Siddiqua; Chinchu Cherian. 2021. "A novel stabilized rammed earth using pulp mill fly ash as alternative low carbon cementing material." Construction and Building Materials 300, no. : 124003.

Original paper
Published: 18 June 2021 in Bulletin of Engineering Geology and the Environment
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Little attention has been paid to investigating borehole deformation characteristics during drilling in soil and rock mixtures commonly encountered in the construction of ground anchors, micropiles, etc., raising questions as to the pile quality. This unique study investigates the deformations of micropile boreholes during rotary drilling in a compacted soil-limestone mixture (S-LM) by developing model tests. Three sets of experiments were carried out, in which three groundwater conditions (no water flow, 40 cm water level, and 80 cm water level) were applied at each of the three boreholes, which had diameters of 32, 44, and 56 mm. The variations in vertical displacement, deep horizontal displacement, pore water pressure, and soil pressure were recorded during the drilling stage. The test results showed that, in general, the vertical displacement at the ground surface, radial horizontal movement, and soil pressure induced by rotary drilling were strongly correlated with the borehole diameter. It was observed that the larger the borehole diameter was, the higher the values of these parameters. Furthermore, the 80-cm water level resulted in borehole collapse during the drilling stop periods since a negative displacement area and a soil pressure varying from negative to zero were observed. This research broadens the limited study of borehole deformation conducted on soil and rock mixtures via model tests. Additionally, it can provide a reference for micropile designers and contractors planning to drill in similar soil-rock mixtures.

ACS Style

Chunye Ying; Xinli Hu; Sumi Siddiqua; Gehad Mohamed Hossam Makeen; Peng Xia; Chu Xu; Qiang Wang. Model tests for observing the deformation characteristics of micropile boreholes during drilling in a soil-limestone mixture. Bulletin of Engineering Geology and the Environment 2021, 1 -21.

AMA Style

Chunye Ying, Xinli Hu, Sumi Siddiqua, Gehad Mohamed Hossam Makeen, Peng Xia, Chu Xu, Qiang Wang. Model tests for observing the deformation characteristics of micropile boreholes during drilling in a soil-limestone mixture. Bulletin of Engineering Geology and the Environment. 2021; ():1-21.

Chicago/Turabian Style

Chunye Ying; Xinli Hu; Sumi Siddiqua; Gehad Mohamed Hossam Makeen; Peng Xia; Chu Xu; Qiang Wang. 2021. "Model tests for observing the deformation characteristics of micropile boreholes during drilling in a soil-limestone mixture." Bulletin of Engineering Geology and the Environment , no. : 1-21.

Journal article
Published: 04 June 2021 in Construction and Building Materials
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In this paper, the cyclic behavior of Rammed Earth (RE) elements is investigated by imposing strain-controlled cyclic loads. RE samples comprise plain soil, Waste Tire Textile Fiber (WTTF)-reinforced specimens (FR), cement-stabilized specimens (CS), and simultaneously reinforced and stabilized (CSFR) specimens. Cyclic properties and responses such as maximum stress, plastic strain, dynamic elastic modulus, damage, and plastic strain energy are evaluated. Two models are also proposed and tested against the experimental data for predicting the plastic strain and damage in different loading cycles. CT-Scan images are also provided for visual inspection of fractures and crack growth. Based on the results, plain and CS samples are found to show the weakest cyclic behavior, since they experience high maximum stress reduction, dynamic elastic modulus deterioration, damage, and plastic strain energy. Extensive and continuous cracks are also detected in these specimens according to CT-Scan images. On the other hand, CSFR specimens enjoy both high strengths induced by cement stabilization and ductility imparted as a result of fiber reinforcement. CSFR specimens with high fiber contents undergo relatively low maximum strength reduction, dynamic elastic modulus deterioration, damage, and plastic strain energy. FR specimens are also found to display relatively decent cyclic behavior. As a result, it is deduced that among the tested soil mixtures, CSFR specimens (with a WTTF content higher than 2%) have the most suitable performance under cyclic loadings.

ACS Style

Shayan Sheikhi Narani; Pouria Zare; Mohsen Abbaspour; Ahmad Fahimifar; Sumi Siddiqua; Seyed Majdeddin Mir Mohammad Hosseini. Evaluation of fiber-reinforced and cement-stabilized rammed-earth composite under cyclic loading. Construction and Building Materials 2021, 296, 123746 .

AMA Style

Shayan Sheikhi Narani, Pouria Zare, Mohsen Abbaspour, Ahmad Fahimifar, Sumi Siddiqua, Seyed Majdeddin Mir Mohammad Hosseini. Evaluation of fiber-reinforced and cement-stabilized rammed-earth composite under cyclic loading. Construction and Building Materials. 2021; 296 ():123746.

Chicago/Turabian Style

Shayan Sheikhi Narani; Pouria Zare; Mohsen Abbaspour; Ahmad Fahimifar; Sumi Siddiqua; Seyed Majdeddin Mir Mohammad Hosseini. 2021. "Evaluation of fiber-reinforced and cement-stabilized rammed-earth composite under cyclic loading." Construction and Building Materials 296, no. : 123746.

Journal article
Published: 19 March 2021 in Journal of Cleaner Production
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The inorganic solid waste generated in pulp and paper industries called pulp mill fly ash (PFA) is a potentially valuable resource as supplementary cementitious material. However, large PFA volume is discarded in landfills due to stringent environmental regulations and lack of proper guidelines for safe alternative applications, thereby posing substantial environmental liability. The present study investigated the effectiveness of recycled PFA as a green binder for stabilizing weak silty sand pavement subgrades by conducting a series of laboratory experiments. The important physicochemical and ecotoxicological properties of PFA indicated its valuable potential for beneficial application as an energy-efficient and low embodied carbon construction raw material. Further, the substantial soil strength and stiffness after PFA treatment and short-term curing under ambient conditions indicated its efficiency as an effective stabilizer. The dramatic improvement was mainly due to the hydration reactions of calcium-rich PFA, leading to stable cementitious compounds. Microstructural evolution of PFA treated and cured soil revealed the formation and deposition of new products in the inter and intra-aggregate pores, thereby forming strong inter-particle bonds and a dense matrix with refined pore structure. Further, the leaching tests confirmed that the cementation process minimized the bio-availability of toxic metals present in the treated soil by encapsulating in the newly formed water-stable compounds. These results demonstrated that recycled PFA could be successfully implemented as an environmentally and economically sustainable binder in road construction and rehabilitation applications, reducing stockpiles of this waste and associated ecological footprints.

ACS Style

Chinchu Cherian; Sumi Siddiqua. Engineering and environmental evaluation for utilization of recycled pulp mill fly ash as binder in sustainable road construction. Journal of Cleaner Production 2021, 298, 126758 .

AMA Style

Chinchu Cherian, Sumi Siddiqua. Engineering and environmental evaluation for utilization of recycled pulp mill fly ash as binder in sustainable road construction. Journal of Cleaner Production. 2021; 298 ():126758.

Chicago/Turabian Style

Chinchu Cherian; Sumi Siddiqua. 2021. "Engineering and environmental evaluation for utilization of recycled pulp mill fly ash as binder in sustainable road construction." Journal of Cleaner Production 298, no. : 126758.

Review
Published: 01 March 2021 in Geotechnical and Geological Engineering
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Organic soils are considered one of the most problematic soils due to their high compressibility and low shear strength at small strains. Characterizing organic soils based on their simple index properties is useful for the preliminary design stages of construction projects. There are three main index properties used for assessing organic soils properties, namely: the water content, the organic content, and the fiber content. Organic soils are distinguished by their relatively high water content. The organic content includes the carbonaceous and combustible components. Whereas the fiber content accounts for the presence of fibers in organic soils based on their botanical composition and the degree of decomposition. The data available in literature regarding organic soils parameters (index, compressibility and shear strength) were collected and analyzed in this study to obtain new correlations between the different organic soil parameters, and the simple index parameters (water content and organic content). The available correlations found in the literature depend on relating a certain parameter with either the organic content or water content. However, the organic content and the water content are related. Hence, the proposed correlations presented in this study aim to connect the particular soil parameter with both the water content and the organic content, using the same equation. Unfortunately, there is not much data in the literature about the soil texture or fiber content, and their relation with other parameters. Hence, all the proposed correlations in this study are not considering the fibre content or the soil fabric.

ACS Style

Ahmed ElMouchi; Sumi Siddiqua; Dharma Wijewickreme; Herbert Polinder. A Review to Develop new Correlations for Geotechnical Properties of Organic Soils. Geotechnical and Geological Engineering 2021, 39, 3315 -3336.

AMA Style

Ahmed ElMouchi, Sumi Siddiqua, Dharma Wijewickreme, Herbert Polinder. A Review to Develop new Correlations for Geotechnical Properties of Organic Soils. Geotechnical and Geological Engineering. 2021; 39 (5):3315-3336.

Chicago/Turabian Style

Ahmed ElMouchi; Sumi Siddiqua; Dharma Wijewickreme; Herbert Polinder. 2021. "A Review to Develop new Correlations for Geotechnical Properties of Organic Soils." Geotechnical and Geological Engineering 39, no. 5: 3315-3336.

Journal article
Published: 16 February 2021 in Engineering Geology
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Traffic loads induce cyclic loading under influence of environmental factors, and is affected by the variation of moisture content and suction (s). These parameters are difficult to quantify, and the methods for determination are cumbersome. This paper presents extensive experimental studies used to obtain the resilient modulus-suction (MR-s) relationship of the treated subgrade soil. An optimum design of bentonite‑magnesium-alkalinization (BMA) was used an additive. The cyclic Triaxial frame with ELDYN system was employed to measure MR values and the suction was estimated using the filter paper test. A bimodal soil water characteristic curve (SWCC) was observed for treated soil with unheated BMA additive and pre-treatment at heated (BMAH) conditions due to the presence of cementitious products. The MR-s relationship was also developed for the stabilized soil using a normalized model. Results showed that the BMAH samples had a significant level of improvement of MR at higher suction levels as compared to BMA samples but this behaviour of BMAH didn't sustain under fully saturated condition. The change in moisture contents under seasonal variation affects the subgrade performance. This study shows the soil additive can effectively improve the mechanical properties of the soil under various moisture contents. The MR for the treated soil can be estimated using the normalized model under the worst-case scenario of a subgrade when the soil is at a fully saturated condition

ACS Style

Nurmunira Muhammad; Sumi Siddiqua. Moisture-dependent resilient modulus of chemically treated subgrade soil. Engineering Geology 2021, 285, 106028 .

AMA Style

Nurmunira Muhammad, Sumi Siddiqua. Moisture-dependent resilient modulus of chemically treated subgrade soil. Engineering Geology. 2021; 285 ():106028.

Chicago/Turabian Style

Nurmunira Muhammad; Sumi Siddiqua. 2021. "Moisture-dependent resilient modulus of chemically treated subgrade soil." Engineering Geology 285, no. : 106028.

Original paper
Published: 08 February 2021 in Natural Hazards
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The ground motion intensity of an earthquake is significantly changed when seismic waves propagate from the bedrock to the near-surface soft geological materials. The ground where the shear wave velocity (Vs) exists greater than 760 m/s is generally considered as bedrock. As a common practice in the last three decades, the surface ground motion of a soil site is estimated by multiplying the bedrock motion with the site coefficient that is empirically determined from the time-averaged shear wave velocity in the top 30 m (Vs30) of the site. The site coefficient is defined as the ratio of the ground motion intensity at the ground surface to that of the bedrock. If the bedrock of a site exists at a depth of greater than 30 m, the site effect from the depth of 30 m to the bedrock is not accounted in the Vs30-based site coefficient. In Dhaka City, the minimum depth of the bedrock is approximately 175 m. Therefore, the use of the Vs30-based site coefficient to estimate the surface ground motion is not appropriate for the soft and deep sedimentary deposits of this city. In this study, site response analysis using the Vs30-based site coefficient, linear, equivalent-linear, and nonlinear approaches has been performed to estimate the surface ground motion at different sites of Dhaka City and to compare the results of different approaches. It is observed that the surface ground motion is decreased with increasing the depth of the bedrock due to low shear strain and viscous damping in the soft sedimentary deposits.

ACS Style

Zillur Rahman; Sumi Siddiqua; A. S. M. Maksud Kamal. Site response analysis for deep and soft sedimentary deposits of Dhaka City, Bangladesh. Natural Hazards 2021, 106, 2279 -2305.

AMA Style

Zillur Rahman, Sumi Siddiqua, A. S. M. Maksud Kamal. Site response analysis for deep and soft sedimentary deposits of Dhaka City, Bangladesh. Natural Hazards. 2021; 106 (3):2279-2305.

Chicago/Turabian Style

Zillur Rahman; Sumi Siddiqua; A. S. M. Maksud Kamal. 2021. "Site response analysis for deep and soft sedimentary deposits of Dhaka City, Bangladesh." Natural Hazards 106, no. 3: 2279-2305.

Journal article
Published: 10 December 2020 in Environmental Geotechnics
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This paper investigated the role of pore fluid pH in governing the microstructural characteristics of loess soil, and its ultimate effect on collapse mechanisms. A series of standard oedometer tests was conducted to evaluate the impact of acidic and alkaline pore fluid pH on the collapse behavior of loess. The microstructural characterization of soil exposed to different pore fluid pH was done by performing microscopic analysis of specimens before and after oedometer test. In addition, the obtained micrographs were processed using image analysis tool in order to interpret the influence of different pore fluid pH interaction on the evolution of soil pore-size distribution characteristics. The results obtained in this study indicated that the pore fluid pH has significant effect on the structural stability of loess and evolution of pore-size distribution during consolidation, and consequently on its wetting-induced collapse behavior.

ACS Style

Sumi Siddiqua; Amin Bigdeli; Chinchu Cherian. Effect of pore fluid pH on the collapse behaviour and microstructural evolution of a loess. Environmental Geotechnics 2020, 1 -11.

AMA Style

Sumi Siddiqua, Amin Bigdeli, Chinchu Cherian. Effect of pore fluid pH on the collapse behaviour and microstructural evolution of a loess. Environmental Geotechnics. 2020; ():1-11.

Chicago/Turabian Style

Sumi Siddiqua; Amin Bigdeli; Chinchu Cherian. 2020. "Effect of pore fluid pH on the collapse behaviour and microstructural evolution of a loess." Environmental Geotechnics , no. : 1-11.

Technical notes
Published: 23 November 2020 in Landslides
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The prediction of the landslide kinetic features is of great importance in minimizing the potential hazardous impacts and in applying the appropriate stabilization techniques. The present study used the generalized interpolation material point (GIMP) method to analyze the run-out processes of the Xinlu Village landslide that has taken place in Xinlu Village, Chongqing, China, in 2016. The evolutions of equivalent plastic strain, displacement, landslide velocity, and kinematic energy were investigated during the landslide motion. The simulation results indicated that the initial stage of the landslide started with slippage of the mid-front soil part with a maximum velocity of 1.02 m/s (at t = 9 s). The rear rock came to failure at t = 69 s as the tensile crack extended from the landslide surface to the deep weak interlayer. Thereafter, the rear rock further accelerated and pushed the mid-front sliding soil, which formed an overall movement. The kinetic energy of the studied landslide concentrated in the acceleration phases of the soil and rock masses. The predicted landslide geometry and run-out distance had slight differences from the actual ones. Based on the landslide run-out analysis, the studied landslide can be classified as a landslide that simultaneously comprises retrogressive and advancing features. A potential secondary failure of this landslide could happen under specific extreme circumstances.

ACS Style

Chunye Ying; Kun Zhang; Ze-Nian Wang; Sumi Siddiqua; Gehad Mohamed Hossam Makeen; Luqi Wang. Analysis of the run-out processes of the Xinlu Village landslide using the generalized interpolation material point method. Landslides 2020, 18, 1519 -1529.

AMA Style

Chunye Ying, Kun Zhang, Ze-Nian Wang, Sumi Siddiqua, Gehad Mohamed Hossam Makeen, Luqi Wang. Analysis of the run-out processes of the Xinlu Village landslide using the generalized interpolation material point method. Landslides. 2020; 18 (4):1519-1529.

Chicago/Turabian Style

Chunye Ying; Kun Zhang; Ze-Nian Wang; Sumi Siddiqua; Gehad Mohamed Hossam Makeen; Luqi Wang. 2020. "Analysis of the run-out processes of the Xinlu Village landslide using the generalized interpolation material point method." Landslides 18, no. 4: 1519-1529.

Journal article
Published: 13 November 2020 in Applied Clay Science
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Clay nanocomposite hydrogels show great potential in tissue engineering applications due to their large layer space, cationic exchange capability, antimicrobial activity and advances in cell attachment and cell proliferation. Bentonite is a natural clay composed of a multi-layered structure with calcium and sodium cations between the tetrahedral and the octahedral layers. This article presents the development of a nanocomposite hydrogel from bentonite nanoparticles and gelatin methacryloyl (GelMA) for tissue engineering applications by investigating its mechanical, morphological and biocompatibility properties. In this research, two chemical treatment methods were studied on bentonite to manipulate it's drying density and its moisture content as an aim to enhance the mechanical stiffness of bentonite. Compression test was used to compare the mechanical properties of calcium and sodium bentonite-GelMA. It is clear that sodium bentonite enhances the mechanical properties of pure GelMA two times, while calcium bentonite showed no effect. The microstructure analysis showed a difference in the pore size when the concentrations of bentonite were varied. The 3D cell encapsulation experiment showed a maintenance of high cell viability over 5 days. The content covered in this paper will be an introduction for bentonite-GelMA nanocomposite hydrogels for further research studies in tissue engineering.

ACS Style

Mahmoud A. Sakr; Mohamed G.A. Mohamed; Ruolin Wu; Su Ryon Shin; Daniel Kim; Keekyoung Kim; Sumi Siddiqua. Development of bentonite-gelatin nanocomposite hybrid hydrogels for tissue engineering. Applied Clay Science 2020, 199, 105860 .

AMA Style

Mahmoud A. Sakr, Mohamed G.A. Mohamed, Ruolin Wu, Su Ryon Shin, Daniel Kim, Keekyoung Kim, Sumi Siddiqua. Development of bentonite-gelatin nanocomposite hybrid hydrogels for tissue engineering. Applied Clay Science. 2020; 199 ():105860.

Chicago/Turabian Style

Mahmoud A. Sakr; Mohamed G.A. Mohamed; Ruolin Wu; Su Ryon Shin; Daniel Kim; Keekyoung Kim; Sumi Siddiqua. 2020. "Development of bentonite-gelatin nanocomposite hybrid hydrogels for tissue engineering." Applied Clay Science 199, no. : 105860.

Original paper
Published: 18 July 2020 in Bulletin of Engineering Geology and the Environment
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During Yangtze River reservoir impoundment, the widely distributed natural soil on the bank landslide experiences long-term water immersion. The later has a significant effect on soil deterioration, which may also aggravate landslide deformation and even cause landslide triggering. However, scarce attention has been paid to investigate the performance of bank soil immersed in reservoir water for a long period and its possible contribution to landslide deformation. This paper investigates the chemo-mechanical behavior of silty soil in the Three Gorges Reservoir area subjected to long-term Yangtze River water immersion. Chemical and mineralogical analyses, in addition to oedometer and triaxial shear tests, were carried out before and after immersion to investigate the effect of water immersion on the tested soil properties. The results showed considerable change in the soil chemo-mechanical properties induced by water immersion. The changes comprised a slow dissolution of carbonates over time, which became notable at 7 days of immersion, an increase in the silt percentage on the expense of clay, which was observed during the first stage of immersion. The effect of immersion time on the progressive change in the soil properties was dominated at 7 days, but it eventually reached equilibrium at approximately 20 days. The results indicate that soil volume change and deterioration of strength are strongly correlated to the dissolution of carbonates and changes in the soil particle size distribution.

ACS Style

Chunye Ying; Xinli Hu; Chang Zhou; Sumi Siddiqua; Gehad Mohamed Hossam Makeen; Qiang Wang; Chu Xu. Analysis of chemo-mechanical behavior of silty soil under long-term immersion in saline reservoir water. Bulletin of Engineering Geology and the Environment 2020, 80, 627 -640.

AMA Style

Chunye Ying, Xinli Hu, Chang Zhou, Sumi Siddiqua, Gehad Mohamed Hossam Makeen, Qiang Wang, Chu Xu. Analysis of chemo-mechanical behavior of silty soil under long-term immersion in saline reservoir water. Bulletin of Engineering Geology and the Environment. 2020; 80 (1):627-640.

Chicago/Turabian Style

Chunye Ying; Xinli Hu; Chang Zhou; Sumi Siddiqua; Gehad Mohamed Hossam Makeen; Qiang Wang; Chu Xu. 2020. "Analysis of chemo-mechanical behavior of silty soil under long-term immersion in saline reservoir water." Bulletin of Engineering Geology and the Environment 80, no. 1: 627-640.

Original paper
Published: 12 June 2020 in Natural Hazards
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The probabilistic seismic hazard analysis (PSHA) has been performed for Bangladesh using background seismicity, crustal fault, and subduction zone source models. The latest ground motion prediction equations (GMPEs) that are developed using global data sets have been used to estimate ground motion. The uncertainties in seismic sources and GMPEs to estimate ground motion are accounted using the logic tree approach. The activity rates of the background and regional seismicity sources are estimated using a declustered and complete catalog of the study regions. The activity rates of the crustal fault and subduction zone sources are estimated from the geodetic strain rates using the well-accepted relationships. The peak ground acceleration (PGA) and spectral acceleration (SA) at spectral periods of 0.2, 0.5, 1.0, 2.0, 5.0, and 10.0 s have been estimated at a grid size of 0.250 at the bedrock ground condition. The PGA and SA maps of various spectral periods have been prepared for Bangladesh for both 10% and 2% probability of exceedance in 50 years. These seismic hazard maps can be used for seismic risk management of Bangladesh.

ACS Style

Zillur Rahman; Sumi Siddiqua; A. S. M. Maksud Kamal. Seismic source modeling and probabilistic seismic hazard analysis for Bangladesh. Natural Hazards 2020, 103, 2489 -2532.

AMA Style

Zillur Rahman, Sumi Siddiqua, A. S. M. Maksud Kamal. Seismic source modeling and probabilistic seismic hazard analysis for Bangladesh. Natural Hazards. 2020; 103 (2):2489-2532.

Chicago/Turabian Style

Zillur Rahman; Sumi Siddiqua; A. S. M. Maksud Kamal. 2020. "Seismic source modeling and probabilistic seismic hazard analysis for Bangladesh." Natural Hazards 103, no. 2: 2489-2532.

Original article
Published: 04 December 2019 in Environmental Earth Sciences
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Solid waste management is a great concern in the urban areas of the developing countries. A sanitary landfill is an essential facility for efficient management of solid waste to control unpleasant odor, disease-spreading pathogens, and disposable mass. Chittagong, the second largest city in Bangladesh with an ever-increasing population, has three landfill sites within the metropolitan area. The sites are near the residential areas. The waste collection, transportation, and disposal techniques for landfilling are not well established in the city. As a result, solid wastes are randomly thrown into lowlands, rivers, streets, and open drains in an uncontrolled manner. Consequently, these waste deposits act as breeding ground of various disease vectors, such as rats, mosquitoes, flies, cockroaches, and pathogenic microorganisms. The leachate also contaminates groundwater due to improper linear design of the landfills. Therefore, the human health of the city dwellers is at risk due to the contaminated environment of the city. In the present study, the suitability of the existing landfill sites of the city has been evaluated using GIS-based multicriteria analysis technique. The importance of relevant parameters required for landfill site selection has been determined using multicriteria weighted average method. Then, the individual map of each parameter was created and overlaid all maps of different parameters to assess suitability of the landfill sites in terms of suitability score using ArcGIS.

ACS Style

Ashish Dey; Sumi Siddiqua; Zillur Rahman. Suitability assessment using multicriteria spatial decision support system for the existing landfill sites of Chittagong City, Bangladesh. Environmental Earth Sciences 2019, 78, 702 .

AMA Style

Ashish Dey, Sumi Siddiqua, Zillur Rahman. Suitability assessment using multicriteria spatial decision support system for the existing landfill sites of Chittagong City, Bangladesh. Environmental Earth Sciences. 2019; 78 (24):702.

Chicago/Turabian Style

Ashish Dey; Sumi Siddiqua; Zillur Rahman. 2019. "Suitability assessment using multicriteria spatial decision support system for the existing landfill sites of Chittagong City, Bangladesh." Environmental Earth Sciences 78, no. 24: 702.

Technical note
Published: 13 November 2019 in Geotechnical and Geological Engineering
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Highly compacted bentonite is an engineered barrier material that is being examined in the Canadian concept for storage of used fuel bundle in a deep geological repository. Having an estimation of the in situ ground water salinity will help to predict hydro-mechanical behavior of the engineered barriers as well as understanding of any potential corrosion of the cylinders of the used fuel bundles. The current research investigates the impact of pore fluid chemistry on the electrical resistivity of highly compacted bentonite. In these tests, pore fluid solutions were selected to represent groundwater salinity of host rocks locations of the Canadian DGR. Former studies found that electrical resistivity is a powerful tool to monitor the degree of saturation of barrier materials. Following the similar approach, this study suggests that the salinity of the highly compacted bentonite can be monitored by means of electrical resistivity to acquire a clearer picture of the deep geological repository’s performance.

ACS Style

Sumi Siddiqua; Sepehr Rahimi. Developing a Relation Between Pore Fluid Salinity and Electrical Resistivity of Highly Compacted Bentonite. Geotechnical and Geological Engineering 2019, 38, 2345 -2350.

AMA Style

Sumi Siddiqua, Sepehr Rahimi. Developing a Relation Between Pore Fluid Salinity and Electrical Resistivity of Highly Compacted Bentonite. Geotechnical and Geological Engineering. 2019; 38 (2):2345-2350.

Chicago/Turabian Style

Sumi Siddiqua; Sepehr Rahimi. 2019. "Developing a Relation Between Pore Fluid Salinity and Electrical Resistivity of Highly Compacted Bentonite." Geotechnical and Geological Engineering 38, no. 2: 2345-2350.

Journal article
Published: 31 October 2019 in Applied Clay Science
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This paper investigates the mechanical, physicochemical, and microstructural characterization of treated silty sand using a novel additive. The additive from a mixture of bentonite, magnesium chloride, and alkaline solution was introduced for stabilization of soil. Atterberg limits, compaction, pH, and unconfined compressive strength (UCS) tests were used to assess the mechanical and physicochemical properties of the stabilized soil. Further investigation results on the optimum designed sample are discussed based on microstructural analysis using X-ray powder diffraction (XRD), field emission scanning electron microscopy (FESEM), Energy Dispersive Spectroscopy (EDS), and Fourier transform infrared spectroscopy (FTIR). Two curing types: unheated and heated at 60 °C for 24 h, were observed at 7, 14, 28 and 60 days in ambient temperature. Overall, it was found that the chemical additive improved the compressive strength of the soil and the heated curing tests showed significant strength improvement. The mechanical and physicochemical results revealed an optimum mix to improve silty sand strength using the addition of 40% bentonite with an alkaline activator (SS/SH) ratio of 0.5, an alkaline activator-to-MgCl2 (L/S) ratio of 0.7, and 3% MgCl2 by dry weight of the soil under heat curing condition at 60 °C for 24 h. The microstructure analysis confirmed the formation of the cementitious products, such as calcium aluminium silicate hydrate (C-(A)-S-H) and magnesium silicate hydrate (M-S-H) in the treated sample.

ACS Style

Nurmunira Muhammad; Sumi Siddiqua. Stabilization of silty sand using bentonite‑magnesium-alkalinization: Mechanical, physicochemical and microstructural characterization. Applied Clay Science 2019, 183, 105325 .

AMA Style

Nurmunira Muhammad, Sumi Siddiqua. Stabilization of silty sand using bentonite‑magnesium-alkalinization: Mechanical, physicochemical and microstructural characterization. Applied Clay Science. 2019; 183 ():105325.

Chicago/Turabian Style

Nurmunira Muhammad; Sumi Siddiqua. 2019. "Stabilization of silty sand using bentonite‑magnesium-alkalinization: Mechanical, physicochemical and microstructural characterization." Applied Clay Science 183, no. : 105325.

Journal article
Published: 23 September 2019 in Transportation Geotechnics
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The properties and performance of alkali activated geopolymers are dominated by several factors such as initial curing conditions, concentration of alkaline activators and composition of materials. This study aimed at to investigate the effect of curing temperature and duration on unconfined compressive strength, elastic modulus (E50) and microstructure of subgrade soil stabilized with bentonite magnesium alkalization. The selected curing temperatures and durations included ambient temperature, 40°C, 60°C and 80°C for 1 to 3 days. Results revealed that curing at ambient temperature or as low as 40°C is not enough to achieve desirable strength while further increase in temperature favored substantial strength development. The optimal development of unconfined compressive strength and E50 observed when samples cured at 60°C for 3 days and the degree of improvement is 7 times compared to the natural soil. In addition, the Scanning Electron Microscopy (SEM) images revealed presence of cementitious gel resulted from stabilization process. The data from Energy-Dispersive Spectroscopy (EDS) and thermogravimetric analysis (TGA) confirmed the cementitious gel as magnesium silicate hydrate (M-S-H) and calcium silicate hydrate (C-S-H) and the formation of these bonds made the samples more compacted and stable with time.

ACS Style

Sohana Sabrin; Sumi Siddiqua; Nurmunira Muhammad. Understanding the effect of heat treatment on subgrade soil stabilized with bentonite and magnesium alkalinization. Transportation Geotechnics 2019, 21, 100287 .

AMA Style

Sohana Sabrin, Sumi Siddiqua, Nurmunira Muhammad. Understanding the effect of heat treatment on subgrade soil stabilized with bentonite and magnesium alkalinization. Transportation Geotechnics. 2019; 21 ():100287.

Chicago/Turabian Style

Sohana Sabrin; Sumi Siddiqua; Nurmunira Muhammad. 2019. "Understanding the effect of heat treatment on subgrade soil stabilized with bentonite and magnesium alkalinization." Transportation Geotechnics 21, no. : 100287.

Review
Published: 14 August 2019 in Sustainability
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The continual growth of pulp and paper industry has led to the generation of tremendous volumes of fly ash as byproducts of biomass combustion processes. Commonly, a major part of it is landfilled; however, updated environmental regulations have tended to restrict the landfilling of fly ash due to rising disposal costs and the scarcity of suitable land. The pulp and paper industries are therefore urgently seeking energy-efficient mechanisms and management for the beneficial use of fly ash in an ecological and economical manner. This paper offers a comprehensive review of existing knowledge on the major physicochemical and toxicological properties of pulp and paper mill fly ash to assess its suitability for various bound and unbound applications. The current state of various methods used for the valorization of pulp and paper mill fly ash into more sustainable geomaterials is briefly discussed. This paper also presents promising and innovative applications for pulp and paper mill fly ash, with particular reference to agriculture and forestry, the construction and geotechnical industries, and the immobilization of contaminants. It was identified from a literature review that modified pulp and paper mill fly ash can be environmentally and economically advantageous over commercial coal-based fly ash in various sustainable applications.

ACS Style

Chinchu Cherian; Sumi Siddiqua. Pulp and Paper Mill Fly Ash: A Review. Sustainability 2019, 11, 4394 .

AMA Style

Chinchu Cherian, Sumi Siddiqua. Pulp and Paper Mill Fly Ash: A Review. Sustainability. 2019; 11 (16):4394.

Chicago/Turabian Style

Chinchu Cherian; Sumi Siddiqua. 2019. "Pulp and Paper Mill Fly Ash: A Review." Sustainability 11, no. 16: 4394.

Journal article
Published: 01 November 2018 in International Journal of Geomechanics
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Protecting the environment from hazardous pollutants associated with waste generation and disposal is a major concern that warrants further investigation. Chemical stabilization is commonly used to improve the engineering properties of soils. The current study examines the characteristics of uncontaminated and copper-contaminated clays stabilized by gypsum. Two clay types, including bentonite (with predominantly montmorillonite mineralogy) and kaolin (with predominantly kaolinite mineralogy), were tested, representing high-swelling and low-strength clays, respectively. An extensive laboratory-testing matrix was developed to investigate the effects of gypsum and copper (Cu) concentrations on the engineering properties of the tested clays, including compaction, Atterberg limits, and unconfined compressive strength (UCS). Additionally, X-ray diffraction, field-emission scanning electron microscopy (FESEM), and X-ray fluorescence tests were conducted to understand the microstructural mechanisms controlling the changes in the engineering properties of the stabilized clays. The UCS test results showed that 7 and 9% gypsum content were optimal for uncontaminated bentonite and kaolin, respectively. The microstructural tests revealed that the added gypsum modified the porous network of the stabilized clays. The level of Cu concentration was found to have a considerable influence on the engineering properties, phases of hydration products formed, and microstructural characteristics of the stabilized clays. These changes are attributed to the retardant effect of Cu on hydration and pozzolanic reactions, which in turn alter the phases of hydration products and cementation structure—the bonding of the clays. The findings suggest that gypsum can offer an economic and effective additive for clay stabilization.

ACS Style

Nima Latifi; Farshid Vahedifard; Sumi Siddiqua; Suksun Horpibulsuk. Solidification–Stabilization of Heavy Metal–Contaminated Clays Using Gypsum: Multiscale Assessment. International Journal of Geomechanics 2018, 18, 04018150 .

AMA Style

Nima Latifi, Farshid Vahedifard, Sumi Siddiqua, Suksun Horpibulsuk. Solidification–Stabilization of Heavy Metal–Contaminated Clays Using Gypsum: Multiscale Assessment. International Journal of Geomechanics. 2018; 18 (11):04018150.

Chicago/Turabian Style

Nima Latifi; Farshid Vahedifard; Sumi Siddiqua; Suksun Horpibulsuk. 2018. "Solidification–Stabilization of Heavy Metal–Contaminated Clays Using Gypsum: Multiscale Assessment." International Journal of Geomechanics 18, no. 11: 04018150.