This page has only limited features, please log in for full access.
Impact resistance, water transport properties and sodium sulphate attack are important criteria to determine the performance of concrete incorporating mixed types of recycled plastic waste. Nine mixes were designed with different combinations of the three plastic types; Polyethylene terephthalate (PET), High density polyethylene (HDPE) and Polypropylene (PP). The plastic partially substituted the coarse aggregate (by volume) at various replacement ratios; 10%, 15%, 20% and 30%. The impact resistance and water transport properties were evaluated for nine mixes while sodium sulphate attack test was performed for three mixes. The results showed that the addition of mixed recycled plastic in concrete improved the impact resistance. The highest impact resistance improvement was achieved by R8 (PET + HDPE + PP) at 30% replacement which was 4.5 times better than the control mix. Water absorption results indicated a slight increase in all plastic mixes while contradictory results were observed for sorptivity test. Analysis of sodium sulphate attack results showed that incorporating 30% mixed plastic reduced the sodium sulphate resistance slightly due to the collective effect of plastic entrapping of sulphate ions after 80 cycles. This study has shown some positive results relating to the impact performance of Mixed Recycled Plastic Concrete (MRPC) which enhances its use in a sustainable way.
Mahmoud Abu-Saleem; Yan Zhuge; Reza Hassanli; Mark Ellis; Mizanur Rahman; Peter Levett. Impact Resistance and Sodium Sulphate Attack Testing of Concrete Incorporating Mixed Types of Recycled Plastic Waste. Sustainability 2021, 13, 9521 .
AMA StyleMahmoud Abu-Saleem, Yan Zhuge, Reza Hassanli, Mark Ellis, Mizanur Rahman, Peter Levett. Impact Resistance and Sodium Sulphate Attack Testing of Concrete Incorporating Mixed Types of Recycled Plastic Waste. Sustainability. 2021; 13 (17):9521.
Chicago/Turabian StyleMahmoud Abu-Saleem; Yan Zhuge; Reza Hassanli; Mark Ellis; Mizanur Rahman; Peter Levett. 2021. "Impact Resistance and Sodium Sulphate Attack Testing of Concrete Incorporating Mixed Types of Recycled Plastic Waste." Sustainability 13, no. 17: 9521.
The critical state (CS), the anchor concept in the critical state soil mechanics (CSSM) framework, has been comprehensively evaluated in triaxial stress conditions, where all the principal stresses are known but the pure shear stresses in the shear directions are absent. Therefore, the evolution of first and second invariants of the stress tensor (σ′) i.e. the mean effective stress (p′) and deviatoric stress (q) along with volumetric strain (εv) is often used to identify the CS. However, the same does not apply for a direct simple shear (DSS) test, which is more representative of the real ground condition, as in most cases the minor principal stresses are not measured. This leads to the challenge of determining the CS line in the e-log(p') space and thus the concept of state parameter (ψ) cannot be used to characterise soil behaviour. Using DEM, this study evaluates CS for DSS, using evolution σ′ and εv, in the e-σ'N space, compare its location with triaxial CS lines in the e-log(p') space. The CS line for DSS in e-σ'N space was then used to define a modified state parameter, ψ, (ψm). It was found that both ψ and ψm showed good correlations with characteristic behaviour e.g. onset of liquefaction, phase transformation state, fabric anisotropy etc. Therefore, ψm maybe a good alternative of ψ for DSS test where the minor principal effective stresses are not measured to define a CSL in e-log(p') space.
Hoang Bao Khoi Nguyen; Mizanur Rahman; Andy Fourie. The critical state behaviour of granular material in triaxial and direct simple shear condition: A DEM approach. Computers and Geotechnics 2021, 138, 104325 .
AMA StyleHoang Bao Khoi Nguyen, Mizanur Rahman, Andy Fourie. The critical state behaviour of granular material in triaxial and direct simple shear condition: A DEM approach. Computers and Geotechnics. 2021; 138 ():104325.
Chicago/Turabian StyleHoang Bao Khoi Nguyen; Mizanur Rahman; Andy Fourie. 2021. "The critical state behaviour of granular material in triaxial and direct simple shear condition: A DEM approach." Computers and Geotechnics 138, no. : 104325.
Mizanur Rahman. The State of Art on Equivalent State Theory for Silty Sands. Understanding Built Environment 2021, 225 -246.
AMA StyleMizanur Rahman. The State of Art on Equivalent State Theory for Silty Sands. Understanding Built Environment. 2021; ():225-246.
Chicago/Turabian StyleMizanur Rahman. 2021. "The State of Art on Equivalent State Theory for Silty Sands." Understanding Built Environment , no. : 225-246.
Enzyme-induced carbonate precipitation (EICP) is a bio-cementation technique and a sustainable method of ground improvement. This study examines the influence of the concentrations of substrates [S 0] and enzymes [E 0] as well as enzyme activity (A E) on the calcium carbonate (CaCO3) precipitation ratio (PR) using 130 test-tube experiments. It was found that the effect of enzyme concentration and activity on PR can be explained using a normalisation of [E s] = [E 0] × A E, where [E s] is the adjusted enzyme concentration. PR increased non-linearly with increasing [E s]/[S 0] and reached 100% at a threshold [E s]/[S 0] value of approximately 20 kU/mol. An exponential function was developed that could capture the relationship between PR and [E s]/[S 0] with reasonable accuracy. This observation was further evaluated with data from the literature consisting of a further 100 test-tube experiments. EICP solutions consisting of [E s]/[S 0] = 20 kU/mol were found to be optimum for soil treatment. The established function was later extended to predict strength gain as measured by the unconfined compressive strength (UCS) and the splitting tensile strength (STS) for EICP-treated soils and could predict the strength gain (UCS/STS) with reasonable accuracy. Results from scanning electron microscopy images, energy-dispersive X-ray spectroscopy and X-ray powder diffraction showed that the precipitated calcium carbonate in test tubes and treated soil was mostly calcite crystals with different morphologies, possibly due to the level of purity of the urease enzyme used.
Isaac Ahenkorah; Mizanur Rahman; Rajibul Karim; Simon Beecham. Optimisation of chemical constituents on enzyme-induced carbonate precipitation in test-tube and soil. Geotechnical Research 2021, 1 -19.
AMA StyleIsaac Ahenkorah, Mizanur Rahman, Rajibul Karim, Simon Beecham. Optimisation of chemical constituents on enzyme-induced carbonate precipitation in test-tube and soil. Geotechnical Research. 2021; ():1-19.
Chicago/Turabian StyleIsaac Ahenkorah; Mizanur Rahman; Rajibul Karim; Simon Beecham. 2021. "Optimisation of chemical constituents on enzyme-induced carbonate precipitation in test-tube and soil." Geotechnical Research , no. : 1-19.
Different types of recycled plastic have been used in concrete and most studies have focused on the behaviour of a single type of plastic. However, separating plastic wastes increases the cost and time of processing. To tackle this problem, this research presents an experimental investigation to determine the effect of incorporating different combinations of three types of recycled plastic waste aggregates—Polyethylene terephthalate (PET), High Density Polyethylene (HDPE) and Polypropylene (PP)—at different replacement ratios of coarse aggregate on physical and mechanical properties of concrete. The combinations include two plastic types at 10% and 20% replacement ratios and three plastic types at 15% and 30% replacement ratios. The performance of the plastic concrete was assessed based on various physical and mechanical properties including workability, fresh and dry densities, air content, compressive, indirect tensile and flexural strengths, modulus of elasticity, stress-strain behaviour and ultrasonic pulse velocity. It is found that the workability of Mixed Recycled Plastic Concrete (MRPC) at a low replacement rate is independent of the type of plastic. The minimum reduction in the compressive strength, indirect tensile and modulus of elasticity were achieved by R3 (PET + PP) at 10% replacement, while R5 (HDPE + PP) at 10% replacement achieved the highest flexural strength and ultrasonic pulse velocity values. The findings suggest that the mixed recycled plastics have a good possibility to partially replace coarse aggregates in concrete which will benefit the plastics recycling community and environment. Furthermore, the study will provide guidance to the concrete industry concerning the effect of the implementation of unsorted mixed types of plastic as coarse aggregates in the production of concrete.
Mahmoud Abu-Saleem; Yan Zhuge; Reza Hassanli; Mark Ellis; Mizanur Rahman; Peter Levett. Stress-Strain Behaviour and Mechanical Strengths of Concrete Incorporating Mixed Recycled Plastics. Journal of Composites Science 2021, 5, 146 .
AMA StyleMahmoud Abu-Saleem, Yan Zhuge, Reza Hassanli, Mark Ellis, Mizanur Rahman, Peter Levett. Stress-Strain Behaviour and Mechanical Strengths of Concrete Incorporating Mixed Recycled Plastics. Journal of Composites Science. 2021; 5 (6):146.
Chicago/Turabian StyleMahmoud Abu-Saleem; Yan Zhuge; Reza Hassanli; Mark Ellis; Mizanur Rahman; Peter Levett. 2021. "Stress-Strain Behaviour and Mechanical Strengths of Concrete Incorporating Mixed Recycled Plastics." Journal of Composites Science 5, no. 6: 146.
DEM was used to simulate constant volume (undrained) triaxial compression tests for coarse particles (sand) mixed with non-plastic fines. Simulations were performed on granular mixtures with a range of fine contents (fc), i.e. 0, 0.05, 0.10 and 0.20. The critical state and micromechanical responses of these mixtures were evaluated. The influence of fc on sand behaviour was captured when fc
Nick Barnett; Mizanur Rahman; Rajibul Karim; H. B. Khoi Nguyen; Joao Antonio Harb Carraro. Equivalent state theory for mixtures of sand with non-plastic fines: a DEM investigation. Géotechnique 2021, 71, 423 -440.
AMA StyleNick Barnett, Mizanur Rahman, Rajibul Karim, H. B. Khoi Nguyen, Joao Antonio Harb Carraro. Equivalent state theory for mixtures of sand with non-plastic fines: a DEM investigation. Géotechnique. 2021; 71 (5):423-440.
Chicago/Turabian StyleNick Barnett; Mizanur Rahman; Rajibul Karim; H. B. Khoi Nguyen; Joao Antonio Harb Carraro. 2021. "Equivalent state theory for mixtures of sand with non-plastic fines: a DEM investigation." Géotechnique 71, no. 5: 423-440.
Soil contamination not only can cause environmental problems but also lead to a notable change in the mechanical properties of soil. Loess widely distributed over North-West (NW) China is featured with the metastable structure, and chemical contaminants produced especially during the rapid development of NW China in recent years seriously threaten the fragile loess environments. When exposed to chemical contaminants, the impacts on the microstructural characteristics of the loess and the resultant mechanical properties are deemed critical for land reclamation in NW China. In light of this, the microscale structural characteristics of the loess exposed to acetic acid, phosphoric acid, sodium hydroxide, and sodium sulfate respectively are studied using scanning electron microscopy, X-ray diffraction, and energy dispersive spectroscopy tests. Additionally, their resultant macroscale mechanical properties are determined by direct shear tests. The deterioration mechanism regarding the microscale structural characteristics when exposed to the contaminants is revealed, and the resultant macroscale mechanical properties present a good correspondence with the deteriorated microscale structural characteristics. The findings of this work provide some guideposts for contaminated land reclamation in NW China.
Wenle Hu; Wen-Chieh Cheng; Shaojie Wen; Mizanur Rahman. Effects of chemical contamination on microscale structural characteristics of intact loess and resultant macroscale mechanical properties. CATENA 2021, 203, 105361 .
AMA StyleWenle Hu, Wen-Chieh Cheng, Shaojie Wen, Mizanur Rahman. Effects of chemical contamination on microscale structural characteristics of intact loess and resultant macroscale mechanical properties. CATENA. 2021; 203 ():105361.
Chicago/Turabian StyleWenle Hu; Wen-Chieh Cheng; Shaojie Wen; Mizanur Rahman. 2021. "Effects of chemical contamination on microscale structural characteristics of intact loess and resultant macroscale mechanical properties." CATENA 203, no. : 105361.
Cyclic Instability, CI is one of the most catastrophic disasters that occur in geotechnical engineering under cyclic loading conditions. This can arise in many forms and is dependent on cyclic loading pattern. To investigate these failure patterns, a series of undrained cyclic triaxial discrete element method, DEM simulations were performed on loose state of granular materials by employing different loading patterns such as stress reversal, SR and non-stress reversal, NSR conditions. The amplitude of cyclic deviatoric stress, qcyc was chosen in such a way that SR/NSR conditions occur. Resistance to liquefaction could either increase or decrease depending on the type of loading pattern and failure behaviour. Therefore, the effect of loading pattern on cyclic liquefaction behaviour was evaluated with DEM simulations on an assembly of spherical particles. In addition to macro-study, this study will help in capturing micromechanical parameters such as coordination number CN and fabric F under different loading patterns.
Rohini Kolapalli; Mizanur Rahman; Rajibul Karim; Hoang Bao Khoi Nguyen. Effect of Stress Reversal in Cyclic Instability: A DEM Study. Lecture Notes in Civil Engineering 2021, 213 -221.
AMA StyleRohini Kolapalli, Mizanur Rahman, Rajibul Karim, Hoang Bao Khoi Nguyen. Effect of Stress Reversal in Cyclic Instability: A DEM Study. Lecture Notes in Civil Engineering. 2021; ():213-221.
Chicago/Turabian StyleRohini Kolapalli; Mizanur Rahman; Rajibul Karim; Hoang Bao Khoi Nguyen. 2021. "Effect of Stress Reversal in Cyclic Instability: A DEM Study." Lecture Notes in Civil Engineering , no. : 213-221.
This paper reported the quality of life (QoL) of 260 Malaysian parents with autism spectrum disorder (ASD) and factors which influencing it. About half of these parents reported to having good QoL. The factors identified in the double ABCX model showed that perceived social support and sense of coherence (SOC) were mediated by coping strategies and had a positive direct and indirect effect on parents’ QoL. These finding reiterate the importance of social support, coping skills, and strong SOC reflection skills in influencing the QoL of parents with ASD child. We therefore suggest parents to utilize the widely available social and organization supports to gain good QoL, which is also important for the wellbeing of their child.
Mohd Fahmi Ismail; Razitasham Safii; Rosalia Saimon; Mizanur Rahman. Quality of Life Among Malaysian Parents with Autism Spectrum Disorder Child: The Double ABCX Model Approach. Journal of Autism and Developmental Disorders 2021, 1 -11.
AMA StyleMohd Fahmi Ismail, Razitasham Safii, Rosalia Saimon, Mizanur Rahman. Quality of Life Among Malaysian Parents with Autism Spectrum Disorder Child: The Double ABCX Model Approach. Journal of Autism and Developmental Disorders. 2021; ():1-11.
Chicago/Turabian StyleMohd Fahmi Ismail; Razitasham Safii; Rosalia Saimon; Mizanur Rahman. 2021. "Quality of Life Among Malaysian Parents with Autism Spectrum Disorder Child: The Double ABCX Model Approach." Journal of Autism and Developmental Disorders , no. : 1-11.
Enzyme-induced carbonate precipitation (EICP) is a relatively new bio-cementation technique for ground improvement. In EICP, calcium carbonate ( CaCO 3 ) precipitation occurs via urea hydrolysis catalysed by the urease enzyme sourced from plants. EICP offers significant potential for innovative and sustainable engineering applications, including strengthening of soils, remediation of contaminants, enhancement of oil recovery through bio-plugging and other in situ field applications. Given the numerous potential applications of EICP, theoretical understanding of the rate and quantity of CaCO 3 precipitation via the ureolytic chemical reaction is vital for optimising the process. For instance, in a typical EICP process, the rate and quantity of CaCO 3 precipitation can depend significantly on the concentration, activity and kinetic properties of the enzyme used along with the reaction environment such as pH and temperature. This paper reviews the research and development of enzyme-catalysed reactions and its applications for enhancing CaCO 3 precipitation in EICP. The paper also presents the assessment and estimation of kinetic parameters, such as the maximal reaction velocity ( V max ) and the Michaelis constant ( K m ), that are associated with applications in civil and geotechnical engineering. Various models for evaluating the kinetic reactions in EICP are presented and discussed, taking into account the influence of pH, temperature and inhibitors. It is shown that a good understanding of the kinetic properties of the urease enzyme can be useful in the development, optimisation and prediction of the rate of CaCO 3 precipitation in EICP.
Isaac Ahenkorah; Mizanur Rahman; Rajibul Karim; Simon Beecham; Christopher Saint. A Review of Enzyme Induced Carbonate Precipitation (EICP): The Role of Enzyme Kinetics. Sustainable Chemistry 2021, 2, 92 -114.
AMA StyleIsaac Ahenkorah, Mizanur Rahman, Rajibul Karim, Simon Beecham, Christopher Saint. A Review of Enzyme Induced Carbonate Precipitation (EICP): The Role of Enzyme Kinetics. Sustainable Chemistry. 2021; 2 (1):92-114.
Chicago/Turabian StyleIsaac Ahenkorah; Mizanur Rahman; Rajibul Karim; Simon Beecham; Christopher Saint. 2021. "A Review of Enzyme Induced Carbonate Precipitation (EICP): The Role of Enzyme Kinetics." Sustainable Chemistry 2, no. 1: 92-114.
Discrete-element method (DEM) simulations of three-dimensional (3D) assemblies of ellipsoid particles were used to evaluate the critical state (CS) for both drained and undrained (constant volume) conditions. A series of conventional triaxial cyclic liquefaction tests with symmetrical cyclic deviatoric stress (σd) with initial q=0 kPa were simulated to develop a relationship between the cyclic stress ratio (CSR=σd/2σ0′) and the number of cycles required for initial liquefaction (NL), where σ0′ is the mean effective normal stress at the end of consolidation. Both cyclic mobility and instability type behaviors were observed depending on the initial void ratio (e0) and σ0′. The micromechanics quantities, i.e., the coordination number (CN), von Mises fabric (FvM), fabric anisotropy intensity (αc), and stress-strain behavior, suggested that cyclic mobility and instability may depend on the phase transformation and instability state, respectively. The cyclic resistance ratio (CRR15), i.e., CSR at NL=15, showed a unique relation with the initial state parameter (ψ0), irrespective of e0 and σ0′. Two series of postliquefaction monotonic simulations with and without reconsolidation exhibited a unique CS, which perfectly matched with the original CS line. The FvM also reached a unique, narrow range at the CS. The postliquefaction settlement during reconsolidation also showed a linear relation with ψ0.
M. M. Rahman; H. B. K. Nguyen; A. B. Fourie; M. R. Kuhn. Critical State Soil Mechanics for Cyclic Liquefaction and Postliquefaction Behavior: DEM study. Journal of Geotechnical and Geoenvironmental Engineering 2021, 147, 04020166 .
AMA StyleM. M. Rahman, H. B. K. Nguyen, A. B. Fourie, M. R. Kuhn. Critical State Soil Mechanics for Cyclic Liquefaction and Postliquefaction Behavior: DEM study. Journal of Geotechnical and Geoenvironmental Engineering. 2021; 147 (2):04020166.
Chicago/Turabian StyleM. M. Rahman; H. B. K. Nguyen; A. B. Fourie; M. R. Kuhn. 2021. "Critical State Soil Mechanics for Cyclic Liquefaction and Postliquefaction Behavior: DEM study." Journal of Geotechnical and Geoenvironmental Engineering 147, no. 2: 04020166.
The overall effectiveness of bio-cementation techniques such as microbial-induced carbonate precipitation (MICP) or enzyme-induced carbonate precipitation (EICP) can be different due to different sources of urease enzyme and treatment approach used. This paper compares the behaviour of oven-dried MICP and EICP-treated sand from macro and micro-mechanical point of view with the number of treatment cycles and average CaCO3 content used as a comparison basis. The results indicate that in both processes, the CaCO3 content increased with the number of treatment cycles and led to an improvement in strength (unconfined compressive and splitting tensile strength) and stiffness. For similar average CaCO3 content, EICP-treated samples showed significantly higher splitting tensile strength (compared to MICP) even though a slightly smaller amount of precipitates were observed at particle contacts through scanning electron microscopy. This indicates, besides the average CaCO3 content, its distribution along the height of the sample is likely to have a significant contribution towards the strength. X-ray powder diffraction and energy-dispersive X-ray spectroscopy analyses confirmed that precipitated CaCO3 in both types of treatments were mainly calcite crystals with minor traces of aragonite.
I. Ahenkorah; M. M. Rahman; M. R. Karim; P. R. Teasdale. A comparison of mechanical responses for microbial- and enzyme-induced cemented sand. Géotechnique Letters 2020, 10, 559 -567.
AMA StyleI. Ahenkorah, M. M. Rahman, M. R. Karim, P. R. Teasdale. A comparison of mechanical responses for microbial- and enzyme-induced cemented sand. Géotechnique Letters. 2020; 10 (4):559-567.
Chicago/Turabian StyleI. Ahenkorah; M. M. Rahman; M. R. Karim; P. R. Teasdale. 2020. "A comparison of mechanical responses for microbial- and enzyme-induced cemented sand." Géotechnique Letters 10, no. 4: 559-567.
The Loess Plateau has been deemed as a landslide-prone area in northwest China because of the unique platform geomorphology and the wetting-induced loess collapse. The interactions of landslide deposit and terrace sediment have been under-explored in the literature. This lack of research has inhibited the prevention and mitigation of loess landslide. This study summarises a total of 40 loess landslides in the South Jingyang Platform, Shaanxi Province; 4 out of the 40 loess landslides are investigated in detail, with an emphasis on the geomorphology feature and the internal geometry of geology. While the sandbox experiments and the discrete element modelling primarily aimed to reproduce the kinetic process of landslide deposit falling from the platform edge and colliding with terrace sediments. The field observation distinguished three domains that represent varying degrees of interaction between the landslide deposit and the terrace sediments, namely push forward domain, shear up/out domain and original terrace sediment domain. The push forward domain is defined as an area completely contained the loess deposit, with most distinct surface upheaval, while the shear up/out domain is defined as an area that significantly interacts with the push forward domain and possesses remarkable evidence of interactions. The original terrace sediment is defined as an area that is thoroughly not disturbed by the interactions. The internal geometry change and the geomorphology features, induced by the interactions of the deposit with the sediments, are reproduced using the sandbox experiments and the discrete element modelling. The sediments shearing upwards and the occurrence of shear liquefaction are interpreted from perspectives of the velocity of deposit movement and the apparent friction angle. The results are deemed to be useful in enhancing our understanding about the interactions of the landslide deposit with the terrace sediments and countermeasures against loess flowslides in the study area in future.
Zhao Duan; Wen-Chieh Cheng; Jian-Bing Peng; Mizanur Rahman; Hao Tang. Interactions of landslide deposit with terrace sediments: Perspectives from velocity of deposit movement and apparent friction angle. Engineering Geology 2020, 280, 105913 .
AMA StyleZhao Duan, Wen-Chieh Cheng, Jian-Bing Peng, Mizanur Rahman, Hao Tang. Interactions of landslide deposit with terrace sediments: Perspectives from velocity of deposit movement and apparent friction angle. Engineering Geology. 2020; 280 ():105913.
Chicago/Turabian StyleZhao Duan; Wen-Chieh Cheng; Jian-Bing Peng; Mizanur Rahman; Hao Tang. 2020. "Interactions of landslide deposit with terrace sediments: Perspectives from velocity of deposit movement and apparent friction angle." Engineering Geology 280, no. : 105913.
The discrete element method (DEM) has been extensively used to capture the macroscopic and particulate response of granular materials. Although particle rolling (i.e. controlled by rolling resistance) has been acknowledged as a major contributing factor towards micro-mechanical behaviour of idealized spherical granular material, its influence on characteristic behaviour has not been thoroughly investigated within critical state soil mechanics (CSSM) framework. For instance, the influence of particle rolling on characteristic features of undrained and drained behaviour (e.g. phase transformation, characteristic state, instability, dilatancy, critical state) and the state parameter, (ψ) has not been captured. In this study, a series of constant volume (CV) and drained triaxial compression simulations were undertaken using a rolling resistance linear contact model, deployed within a DEM software. The CSSM framework was centrally used to assess the influence of particle rolling tendencies/resistance on CV and drained behaviours from both a macro- and micro-mechanical standpoint. The study advanced the current understanding of the influence of rolling resistance on CS-related behaviour.
N. Barnett; Mizanur Rahman; Rajibul Karim; H. B. K. Nguyen. Evaluating the particle rolling effect on the characteristic features of granular material under the critical state soil mechanics framework. Granular Matter 2020, 22, 1 -24.
AMA StyleN. Barnett, Mizanur Rahman, Rajibul Karim, H. B. K. Nguyen. Evaluating the particle rolling effect on the characteristic features of granular material under the critical state soil mechanics framework. Granular Matter. 2020; 22 (4):1-24.
Chicago/Turabian StyleN. Barnett; Mizanur Rahman; Rajibul Karim; H. B. K. Nguyen. 2020. "Evaluating the particle rolling effect on the characteristic features of granular material under the critical state soil mechanics framework." Granular Matter 22, no. 4: 1-24.
Particulate Matter (PM) pollution is generally considered as a prime indicator of urban air quality and is linked to human health hazards. As vehicles are a vital component of an urban setting, the risks of particulate pollution need to be assessed. An emission modelling is essential for that, and thus stochastic modelling approach involving Monte Carlo simulation technique was applied, aiming to reduce the uncertainty in emission modelling. The risks scenarios for the emissions were generated for 2019 (present state) and 2024 (future), integrating the probability of emissions and the associated AQI (Air Quality Index). Despite the vehicles being a minor source of PM in Dhaka (compared to the contribution from other sources), about one-third of the city is found under high risk due to the exhaust particulate pollution; having the potentiality to cover more than 60% of the city in the coming years, affecting the urban public health sustainability. However, the extent of implementation of planning and management strategies can revert the scenarios for the city, which can plausibly reduce the risk from 80% to 50%, or even to a no-risk state.
Asif Iqbal; Shirina Afroze; Mizanur Rahman. Vehicular PM Emissions and Urban Public Health Sustainability: A Probabilistic Analysis for Dhaka City. Sustainability 2020, 12, 6284 .
AMA StyleAsif Iqbal, Shirina Afroze, Mizanur Rahman. Vehicular PM Emissions and Urban Public Health Sustainability: A Probabilistic Analysis for Dhaka City. Sustainability. 2020; 12 (15):6284.
Chicago/Turabian StyleAsif Iqbal; Shirina Afroze; Mizanur Rahman. 2020. "Vehicular PM Emissions and Urban Public Health Sustainability: A Probabilistic Analysis for Dhaka City." Sustainability 12, no. 15: 6284.
Microbial-induced calcite precipitation (MICP) is a promising new technology in the area of Civil Engineering with potential to become a cost-effective, environmentally friendly and sustainable solution to many problems such as ground improvement, liquefaction remediation, enhancing properties of concrete and so forth. This paper reviews the research and developments over the past 25 years since the first reported application of MICP in 1995. Historical developments in the area, the biological processes involved, the behaviour of improved soils, developments in modelling the behaviour of treated soil and the challenges associated are discussed with a focus on the geotechnical aspects of the problem. The paper also presents an assessment of cost and environmental benefits tied with three application scenarios in pavement construction. It is understood for some applications that at this stage, MICP may not be a cost-effective or even environmentally friendly solution; however, following the latest developments, MICP has the potential to become one.
Mizanur Rahman; Reena N. Hora; Isaac Ahenkorah; Simon Beecham; Rajibul Karim; Asif Iqbal. State-of-the-Art Review of Microbial-Induced Calcite Precipitation and Its Sustainability in Engineering Applications. Sustainability 2020, 12, 6281 .
AMA StyleMizanur Rahman, Reena N. Hora, Isaac Ahenkorah, Simon Beecham, Rajibul Karim, Asif Iqbal. State-of-the-Art Review of Microbial-Induced Calcite Precipitation and Its Sustainability in Engineering Applications. Sustainability. 2020; 12 (15):6281.
Chicago/Turabian StyleMizanur Rahman; Reena N. Hora; Isaac Ahenkorah; Simon Beecham; Rajibul Karim; Asif Iqbal. 2020. "State-of-the-Art Review of Microbial-Induced Calcite Precipitation and Its Sustainability in Engineering Applications." Sustainability 12, no. 15: 6281.
The influence of particle shape was evaluated under drained and undrained (constant volume) condition using three-dimensional (3D) cubical assemblies of spheres, ellipsoids, and cluster of spheres (a combination of seven spheres with two different degrees of overlap) with same particle size distribution. It was found that the peak deviatoric stress, the minimum dilatancy (d=dεvp/dεqp), corresponding stress ratio (ηdmin), the bounding surface dilatancy model, and the location of the critical state line (CSL) both in the e-log(p′) and the q-p′ space were influenced by particle shape. Therefore, four corresponding sets of constitutive parameters for four different particle shapes were implemented in a bounding surface model to predict both drained and undrained (constant volume) discrete element method (DEM) simulation. Good prediction, irrespective of particle shape, indicates that the observed DEM behavior can be adequately captured by the theories of continuum mechanics. Importantly, the majority of the constitutive parameters were influenced by particle shape and can be correlated with simple shape descriptor of sphericity.
Hoang Bao Khoi Nguyen; M. M. Rahman; Andy Fourie. Effect of Particle Shape on Constitutive Relation: DEM Study. Journal of Geotechnical and Geoenvironmental Engineering 2020, 146, 04020058 .
AMA StyleHoang Bao Khoi Nguyen, M. M. Rahman, Andy Fourie. Effect of Particle Shape on Constitutive Relation: DEM Study. Journal of Geotechnical and Geoenvironmental Engineering. 2020; 146 (7):04020058.
Chicago/Turabian StyleHoang Bao Khoi Nguyen; M. M. Rahman; Andy Fourie. 2020. "Effect of Particle Shape on Constitutive Relation: DEM Study." Journal of Geotechnical and Geoenvironmental Engineering 146, no. 7: 04020058.
The mechanistic design of a concrete block pavement (CBP) can be very complicated and often requires the use of computer programs. This paper presents a new mechanistic-empirical method, which is implemented in a computer program (DesignPave) that calculates base course/sub-base thicknesses for a range of design inputs such as traffic load, interlocking properties, and material stiffness. A range of virgin and recycled unbound granular materials were also experimentally tested to characterize them for possible use as base course or sub-base materials. Combining the new mechanistic-empirical method and the range of base course/sub-base course materials (virgin and recycled aggregates), it was found that while a CBP containing recycled aggregates did not offer a significant direct financial benefit based on the characteristics or material costs, the associated environmental benefits were very high.
Mizanur Rahman; Simon Beecham; Asif Iqbal; Rajibul Karim; Abu Taher Md Zillur Rabbi. Sustainability Assessment of Using Recycled Aggregates in Concrete Block Pavements. Sustainability 2020, 12, 4313 .
AMA StyleMizanur Rahman, Simon Beecham, Asif Iqbal, Rajibul Karim, Abu Taher Md Zillur Rabbi. Sustainability Assessment of Using Recycled Aggregates in Concrete Block Pavements. Sustainability. 2020; 12 (10):4313.
Chicago/Turabian StyleMizanur Rahman; Simon Beecham; Asif Iqbal; Rajibul Karim; Abu Taher Md Zillur Rabbi. 2020. "Sustainability Assessment of Using Recycled Aggregates in Concrete Block Pavements." Sustainability 12, no. 10: 4313.
The cyclic shearing response of granular materials is highly influenced by various parameters such as void ratio (e), confining stress (p′), initial static shear stress (qs), cyclic deviatoric stress (qcyc), stress reversal and non-stress reversal conditions. Traditionally, most liquefaction studies evaluated the influence of e, p′, qcyc and reversals on isotropically consolidated specimens where qs is zero. However, a soil element in a level ground is normally or K0 consolidated and hence subjected to a qs. Extensive studies have suggested that qs may dramatically alter the pore water pressure generation (Δu), deviatoric strain (εd) and soil fabric for same e, p′ and qcyc. In order to evaluate the effect of qs alone, it is required to produce replicated specimens through different consolidation paths to achieve different qs. Since, it is hard to replicate specimens and assess soil fabric in laboratory, this study used an alternative approach, discrete element method (DEM), which has reproducibility and trace micromechanical parameters such as coordination number, CN and fabric. It is found that Δu, CN and fabric were significantly affected by consolidation path and corresponding qs conditions. This study provides a good understanding on the effect of qs on cyclic response of soils.
R. Kolapalli; Mizanur Rahman; M. R. Karim; Hoang Bao Khoi Nguyen. A Micromechanical Study on the Effect of Initial Static Shear Stress on Cyclic Shearing Response. Lecture Notes in Civil Engineering 2020, 145 -156.
AMA StyleR. Kolapalli, Mizanur Rahman, M. R. Karim, Hoang Bao Khoi Nguyen. A Micromechanical Study on the Effect of Initial Static Shear Stress on Cyclic Shearing Response. Lecture Notes in Civil Engineering. 2020; ():145-156.
Chicago/Turabian StyleR. Kolapalli; Mizanur Rahman; M. R. Karim; Hoang Bao Khoi Nguyen. 2020. "A Micromechanical Study on the Effect of Initial Static Shear Stress on Cyclic Shearing Response." Lecture Notes in Civil Engineering , no. : 145-156.
Mizanur Rahman; Dominic E L Ong. Editorial. Geotechnical Research 2020, 7, 1 -2.
AMA StyleMizanur Rahman, Dominic E L Ong. Editorial. Geotechnical Research. 2020; 7 (1):1-2.
Chicago/Turabian StyleMizanur Rahman; Dominic E L Ong. 2020. "Editorial." Geotechnical Research 7, no. 1: 1-2.