The Experts below are selected from a list of 13959 Experts worldwide ranked by ideXlab platform
Abir Altabbaa - One of the best experts on this subject based on the ideXlab platform.
-
time dependent performance of Soil Mix technology stabilized solidified contaminated site Soils
Journal of Hazardous Materials, 2015Co-Authors: Fei Wang, Hailing Wang, Abir AltabbaaAbstract:Abstract This paper presents the strength and leaching performance of stabilized/solidified organic and inorganic contaminated site Soil as a function of time and the effectiveness of modified clays applied in this project. Field trials of deep Soil Mixing application of stabilization/solidification (S/S) were performed at a site in Castleford in 2011. A number of binders and addictives were applied in this project including Portland cement (PC), ground granulated blastfurnace slag (GGBS), pulverised fuel ash (PFA), MgO and modified clays. Field trial samples were subjected to unconfined compressive strength (UCS), BS CN 12457 batch leaching test and the extraction of total organics at 28 days and 1.5 years after treatment. The results of UCS test show that the average strength values of Mixes increased from 0–3250 kPa at 28 days to 250–4250 kPa at 1.5 years curing time. The BS EN 12457 leachate concentrations of all metals were well below their drinking water standard, except Ni in some Mixes exceed its drinking water standard at 0.02 mg/l, suggesting that due to varied nature of binders, not all of them have the same efficiency in treating contaminated Soil. The average leachate concentrations of total organics were in the range of 20–160 mg/l at 28 days after treatment and reduced to 18–140 mg/l at 1.5 years. In addition, organo clay (OC)/inorgano–organo clay (IOC) slurries used in this field trial were found to have a negative effect on the strength development, but were very effective in immobilizing heavy metals. The study also illustrates that the surfactants used to modify bentonite in this field trail were not suitable for the major organic pollutants exist in the site Soil in this project.
-
time dependent performance of Soil Mix technology mass stabilised contaminated site Soils
7th International Congress on Environmental Geotechnics : iceg2014, 2014Co-Authors: Fei Wang, Abir AltabbaaAbstract:Soil Mixing Technology (SMT) has emerged as a cost-effective, efficient, versatile, and low risk method for the implementation of a range of in-situ remediation treatments. However, contaminants remain in the ground following SMT, and hence assessment of the time-dependent performance of real projects is essential for the validation of the technology and its wider acceptability amongst stakeholders. The SMT system considered in this paper is mass stabilisation, using the ALLU system, which is an effective technique for combining contaminated Soil remediation and ground improvement treatments on the same site. Field trial samples were obtained from the Soil Mix Remediation Technology (SMiRT) project site which contains both heavy metals and organic contaminants. The purpose of this study was to investigate the effect of different combinations of various binders and dosages on physical, strength and leachability behaviour of the mass stabilised Soils at 1 year after treatment. The binder dosages used were 2.5, 5, and 10% by weight. Samples of the treated Soils were subjected to unconfined compressive strength (UCS) and BS EN 12457 batch leaching test at 40 days and 1 year after treatment. The results show that 1) the strength of the mass stabilised site made ground increased with time; 2) the combination of GGBS:MgO at a ratio of 9:1 has the best strength and leachability performances amongst all Mixes; 3) the leachability of Pb, Cu and Zn meet the drinking water standards; and 4) the leachability of total organics varied for the different Mixes.
-
Soil Mix technology for integrated remediation and ground improvement from laboratory work to field trials
Proceedings of the Fourth International Conference on Grouting and Deep Mixing, 2012Co-Authors: Abir Altabbaa, Rakshya Shrestha, M Liska, Claudiane Ouelletplamondon, S Jegandan, P Barker, R Mcgall, C CritchlowAbstract:Relatively new in the UK, Soil Mix technology applied to the in-situ remediation of contaminated land involves the use of Mixing tools and additives to construct permeable reactive in-ground barriers and low-permeability containment walls and for hot-spot Soil treatment by stabilisation/ solidification. It is a cost effective and versatile approach with numerous environmental advantages. Further commercial advantages can be realised by combining this with ground improvement through the development of a single integrated Soil Mix technology system which is the core objective of Project SMiRT (Soil Mix Remediation Technology). This is a large UK-based R&D project involving academia-industry collaboration with a number of tasks including equipment development, laboratory treatability studies, field trials, stakeholder consultation and dissemination activities. This paper presents aspects of project SMiRT relating to the laboratory treatability study work leading to the design of the field trials. © 2012 American Society of Civil Engineers.
-
metal retention experiments for the design of Soil Mix technology permeable reactive barriers
Clean-soil Air Water, 2011Co-Authors: Claudiane Ouelletplamondon, Rod Lynch, Abir AltabbaaAbstract:Soil-Mix technology is effective for the construction of permeable reactive barriers (PRBs) for in situ groundwater treatment. The objective of this study was to perform initial experiments for the design of Soil-Mix technology PRBs according to (i) sorption isotherm, (ii) reaction kinetics and (iii) mass balance of the contaminants. The four tested reactive systems were: (i) a granular zeolite (clinoptilolite-GZ), (ii) a granular organoclay (GO), (iii) a 1:1-Mixture GZ and model sandy clayey Soil and (iv) a 1:1:1-Mixture of GZ, GO and model Soil. The laboratory experiments consisted of batch tests (volume 900mL and sorbent mass 18g) with a multimetal solution of Pb, Cu, Zn, Cd and Ni. For the adsorption experiment, the initial concentrations ranged from 0.01 to 0.5mM (2.5 to 30mg/L). The maximum metal retention was measured in a batch test (300mg/L for each metal, volume 900mL, sorbent mass 90-4.5g). The reactive material efficiency order was found to be GZ>GZ-Soil Mix>GZ-Soil-GO Mix>GO. Langmuir isotherms modelled the adsorption, even in presence of a Mixed cations solution. Adsorption was energetically favourable and spontaneous in all cases. Metals were removed according to the second order reaction kinetics; GZ and the 1:1-Mix were very similar. The maximum retention capacity was 0.1-0.2mmol/g for Pb in the presence of clinoptilolite; for Cu, Zn, Cd and Ni, it was below 0.05mmol/g for the four reactive systems. Mixing granular zeolite, organoclay and model Soil increased the chemisorption. Providing that GZ is reactive enough for the specific conditions, GZ can be Mixed to obtain the required sorption. Granular clinoptilolite addition to Soil is recommended for PRBs for metal contaminated groundwater. The laboratory experiments consisted of batch tests with a multimetal solution of Pb, Cu, Zn, Cd and Ni. The four reactive materials chosen were granular zeolite, clinoptilolite and model sandy clayey Soil, granular organoclay and a Mix of clinoptilolite, model Soil and organoclay. The reactive material efficiency order was found to be granular clinoptilolite>clinoptilolite-Soil Mix>clinoptilolite-Soil-organoclay Mix>granular organoclay. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
J W C Wong - One of the best experts on this subject based on the ideXlab platform.
-
reutilization of coal fly ash and sewage sludge as an artificial Soil Mix effects of preincubation on Soil physico chemical properties
Bioresource Technology, 1997Co-Authors: J W C WongAbstract:Abstract An experiment was performed to evaluate the importance of pre-incubation on the stabilization of a Soil-Mix composed of coal fly-ash and sewage sludge. Sludge was amended with ash at rates of 0, 5, 10, 35 and 50% (w/w). Each ash-sludge Mixture was Mixed with a loamy Soil at either 1:1 or 1:5 ash-sludge Mixture:Soil (v/v) and then incubated under greenhouse conditions for 42 days. Ash amendment resulted in a decrease in EC, NH + 4 , PO 3− 4 and Zn, but an increase in pH and B for most of the incubation period, especially for Soil with 35 and 50% ash-sludge Mixture added at 1:1 (v/v). Ammonium increased and then decreased, while PO 3− 4 and NO − 3 remained relatively unchanged, in the first 14–21 days and then increased until the end of the incubation period. Soluble Cu of all treatments decreased at the end of incubation except for Soil with 0% ash-sludge Mixture at 1:5 v/v. With an increase in ash amendment rate, both seed germination and root growth of Agropyron elongatum in the Soil extracts increased at each incubation period, indicating the beneficial effect of the fly-ash-sludge Mixture. However, an incubation period of 21 days would be needed to obtain an optimum physico-chemical condition for plant growth.
-
the growth of agropyron elongatum in an artificial Soil Mix from coal fly ash and sewage sludge
Bioresource Technology, 1997Co-Authors: J W C Wong, D C SuAbstract:A greenhouse experiment was performed to evaluate the feasibility of using an artificial Soil medium produced from alkaline coal fly ash and sewage sludge for the growth of Agropyron elongatum (tall wheat grass). Sludge was amended with ash at an application rate of 0, 5, 10, 35 and 50% (w/w). Each Mixture was then Mixed with a loamy Soil at either 1:1 or 1:5 (v/v) and incubated under greenhouse conditions for 3 weeks prior to plant growth experiment. Addition of the ash-sludge Mixture significantly improved the seedling emergence and dry weight yields of Agropyron. Pots with 10% ash-sludge Mixture at 1:5 v/v Soil Mixing ratio had the highest yield, while those with 10 and 35% ash-sludge amendment at 1:1 v/v Soil Mixing ratio had lower dry weight yields but were still higher than that of the control with fertilizer treatment. No deficiency in N and P was noted for the ash-sludge-amended pots at both 1:1 and 1:5. Shoot tissue Ca, Mg and B concentrations increased while K, Fe, Mn and Zn decreased with an increase in ash amendment rate. The root tissue Fe, Mn, Cu and Zn contents were significantly higher than those of the shoot tissue. Hence, no excessive accumulation of heavy metals was noted owing to the ash-sludge amendment. The increased yield even at a high amendment rate of 35% ash-sludge Mixture at 1:1 v/v Soil Mixing ratio indicates the potential use of the ash-sludge Mixture as an artificial Soil Mix for agricultural use.
-
effect of an artificial Soil Mix from coal fly ash and sewage sludge on Soil microbial activity
Biology and Fertility of Soils, 1996Co-Authors: J W C Wong, Ka Man LaiAbstract:An artificial Soil Mix was prepared from coal fly ash and sewage sludge and an experiment was performed to evaluate their effects on Soil microbial respiration. Coal fly ash at 0%, 5%, 10%, 35% and 50% w/w was Mixed with dewatered sewage sludge and then each ash-sludge Mixture was incubated with a sandy Soil at 1:1 v/v at 28°C for 42 days. All treatments showed the same carbon dioxide production pattern with a peak production at day 7 to day 14. Addition of ash-sludge Mixtures to Soil resulted in an increase in carbon dioxide production but the production rate decreased according to the ash amendment rate. The high pH of coal fly ash and the dilution effect of the sludge were the major reasons for the decrease. However, the ecological dose 50% values sharply increased from 26% at day 3 to 39% ash at day 14. This indicates the rapid acclimatization of microorganisms to the fly ash-sludge Mixtures. Therefore, a brief stabilization period may be required for the establishment of Soil microbial populations in Soil amended with ash-sludge Mixtures.
-
the production of artificial Soil Mix from coal fly ash and sewage sludge
Environmental Technology, 1995Co-Authors: J W C WongAbstract:The scarcity of land in Hong Kong makes landfilling an unattractive means for the disposal of sewage sludge and coal fly ash. Therefore, reutilisation of these solid wastes might ease the disposal problems. A glasshouse pot leaching study was performed to evaluate the feasibility of using alkaline fly ash as a stabilisation agent for sewage sludge and the final product being used as a potting medium. Sludge was amended with ash at 0, 5, 10, 35 and 50% (w/w). Each Mixture was then Mixed with a loamy Soil (1:1 v/v) and leached with 600 mL of deionized water prior to plant growth experiment using Agropyron elongatum (Tall wheat grass). Soil pH and electrical conductivity following leaching increased consistently with an increase in ash amendment, from 6.3 to 8.2 and 1.6 to 2.3 dS m−1 respectively. Pots amended with 35% ash showed a significant reduction in Zn, Cu and Cd availability but an increase in B contents. The total dry weight yields of ash amended pots were significantly increased as compared to the ...
Al-tabbaa Abir - One of the best experts on this subject based on the ideXlab platform.
-
Time-dependent performance of Soil Mix technology stabilised/ solidified contaminated site Soils
Journal of Hazardous Materials, 2015Co-Authors: Wang Fei, Wang Hailing, Al-tabbaa AbirAbstract:This paper presents the strength and leaching performance of stabilized/solidified organic and inorganic contaminated site Soil as a function of time and the effectiveness of modified clays applied in this project. Field trials of deep Soil Mixing application of stabilization/solidification (S/S) were performed at a site in Castleford in 2011. A number of binders and addictives were applied in this project including Portland cement (PC), ground granulated blastfurnace slag (GGBS), pulverised fuel ash (PFA), MgO and modified clays. Field trial samples were subjected to unconfined compressive strength (UCS), BS CN 12457 batch leaching test and the extraction of total organics at 28 days and 1.5 years after treatment. The results of UCS test show that the average strength values of Mixes increased from 0–3250 kPa at 28 days to 250–4250 kPa at 1.5 years curing time. The BS EN 12457 leachate concentrations of all metals were well below their drinking water standard, except Ni in some Mixes exceed its drinking water standard at 0.02 mg/l, suggesting that due to varied nature of binders, not all of them have the same efficiency in treating contaminated Soil. The average leachate concentrations of total organics were in the range of 20–160 mg/l at 28 days after treatment and reduced to 18–140 mg/l at 1.5 years. In addition, organo clay (OC)/inorgano–organo clay (IOC) slurries used in this field trial were found to have a negative effect on the strength development, but were very effective in immobilizing heavy metals. The study also illustrates that the surfactants used to modify bentonite in this field trail were not suitable for the major organic pollutants exist in the site Soil in this project.This paper was written to support the SMiRT (Soil Mix remediation technology) project, the funding for which was supplied by the UK Technology Strategy Board with 16 industrial partners (Project TP/5/CON/6/I/H0304E). The project website is at http://www-g.eng.cam.ac.uk/smirt. The authors are grateful to Schlumberger Foundation for its financial help of the PhD studentship for the first author, and many thanks to the proofreading by Fei Jin and David O’Connor.This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/doi:10.1016/j.jhazmat.2015.01.00
Abir Al-tabbaa - One of the best experts on this subject based on the ideXlab platform.
-
Preliminary model development for predicting strength and stiffness of cement-stabilized Soils using artificial neural networks
Computing in Civil Engineering, 2013Co-Authors: O. Wang, Abir Al-tabbaaAbstract:This paper presents ongoing work on data collection and collation from a large number of laboratory cement-stabilization projects worldwide. The aim is to employ Artificial Neural Networks (ANN) to establish relationships between variables, which define the properties of cement-stabilized Soils, and the two parameters determined by the Unconfined Compression Test, the Unconfined Compressive Strength (UCS), and stiffness, using E50 calculated from UCS results. Bayesian predictive neural network models are developed to predict the UCS values of cement-stabilized inorganic clays/silts, as well as sands as a function of selected Soil Mix variables, such as grain size distribution, water content, cement content and curing time. A model which can predict the stiffness values of cement-stabilized clays/silts is also developed and compared to the UCS model. The UCS model results emulate known trends better and provide more accurate estimates than the results from the E50 stiffness model. © 2013 American Society of Civil Engineers.
-
Introduction to the Development of an Information Management System for Soil Mix Technology Using Artificial Neural Networks
Geo-Frontiers 2011, 2011Co-Authors: Rakshya Shrestha, Abir Al-tabbaaAbstract:This paper introduces current work in collating data from different projects using Soil Mix technology and establishing trends using artificial neural networks (ANNs). Variation in unconfined compressive strength as a function of selected Soil Mix variables (e.g., initial Soil water content and binder dosage) is observed through the data compiled from completed and on-going Soil Mixing projects around the world. The potential and feasibility of ANNs in developing predictive models, which take into account a large number of variables, is discussed. The main objective of the work is the management and effective utilization of salient variables and the development of predictive models useful for Soil Mix technology design. Based on the observed success in the predictions made, this paper suggests that neural network analysis for the prediction of properties of Soil Mix systems is feasible. © ASCE 2011.
-
Soil Mix technology for land remediation: recent innovations
Proceedings of the Institution of Civil Engineers - Ground Improvement, 2011Co-Authors: Abir Al-tabbaa, Peter Barker, Chris W. EvansAbstract:The past 15 years have seen increasing applications of Soil Mix technology in land remediation, mainly in stabilisation/solidification treatments and the construction of low-permeability cut-off walls and permeable reactive barriers; clear evidence of the versatility of the technology and its wide-ranging applications. This paper provides an overview of some of the recent innovations of Soil Mix technology in land remediation covering equipment developments and applications, including systems for rectangular panels and trenching systems, treatments, such as chemical oxidation, and additives, such as modified clays, zeolites and reactive magnesia. The paper also provides case studies for such innovations. The paper concludes with an overview of an on-going research and development project SMiRT (Soil Mix Remediation Technology) which will involve field trials on a contaminated site and will employ some of the innovations discussed in the paper. The range of significant advantages that Soil Mix technology n...
-
Influence of curing temperature on the strength of cement-stabilised artificial clays
2009Co-Authors: Abir Al-tabbaa, M. GrisoliaAbstract:The paper present results of a laboratory investigation on the influence of curing temperature and time on the mechanical characterisation of cement-stabilised clays as used in deep Soil Mix applications. Numerical modelling, based on the Arrhenius equation, is also presented. Experimentally, this model was applied to a series of tests performed at different temperatures. For each temperature, unconfined compres- sive strength tests were performed at specific time intervals in order to follow the curing and the increase of strength with time. The clay used was artificial clay made up of 40% kaolin clay and 60% of silt (using silica flour). Three different water contents were used to compare the performance of different soft clays. The results showed that the strength increases with the temperature. It was also found that the activation energy is the same for all three water content clays. Using the numerical modelling long-term behaviour of up to 2.4 years was predicted.
-
Soil Mixing in the UK 1991–2001: state of practice report
Proceedings of the Institution of Civil Engineers - Ground Improvement, 2003Co-Authors: Abir Al-tabbaaAbstract:Soil Mixing in the UK started around 12 years ago. The early Soil Mixing work was carried out for the purposes of excavation support and ground improvement by Cementation Piling and Foundations. Not much work was then performed for this application until recently. Around 1995 Soil Mixing was introduced to the UK for geoenvironmental applications for the containment and remediation of contaminated sites. This paper tells the story of research, developments and applications of Soil Mix technology in the UK over the past 12 years or so. The paper concludes with statements on the current position with regard to Soil Mixing practice in the UK. En Angleterre, on a commence a pratiquer le Mixage des sols il y a 12 ans a peu pres. Les premiers travaux de Mixage ont ete effectues, dans le but de soutenir les excavations et d'ameliorer les sols, par la societe Cementation Piling et Foundations. Ensuite, peu de travaux ont ete effectues dans cette application. Vers 1995, le Mixage du sol a ete introduit en Angleterr...
Fei Wang - One of the best experts on this subject based on the ideXlab platform.
-
time dependent performance of Soil Mix technology stabilized solidified contaminated site Soils
Journal of Hazardous Materials, 2015Co-Authors: Fei Wang, Hailing Wang, Abir AltabbaaAbstract:Abstract This paper presents the strength and leaching performance of stabilized/solidified organic and inorganic contaminated site Soil as a function of time and the effectiveness of modified clays applied in this project. Field trials of deep Soil Mixing application of stabilization/solidification (S/S) were performed at a site in Castleford in 2011. A number of binders and addictives were applied in this project including Portland cement (PC), ground granulated blastfurnace slag (GGBS), pulverised fuel ash (PFA), MgO and modified clays. Field trial samples were subjected to unconfined compressive strength (UCS), BS CN 12457 batch leaching test and the extraction of total organics at 28 days and 1.5 years after treatment. The results of UCS test show that the average strength values of Mixes increased from 0–3250 kPa at 28 days to 250–4250 kPa at 1.5 years curing time. The BS EN 12457 leachate concentrations of all metals were well below their drinking water standard, except Ni in some Mixes exceed its drinking water standard at 0.02 mg/l, suggesting that due to varied nature of binders, not all of them have the same efficiency in treating contaminated Soil. The average leachate concentrations of total organics were in the range of 20–160 mg/l at 28 days after treatment and reduced to 18–140 mg/l at 1.5 years. In addition, organo clay (OC)/inorgano–organo clay (IOC) slurries used in this field trial were found to have a negative effect on the strength development, but were very effective in immobilizing heavy metals. The study also illustrates that the surfactants used to modify bentonite in this field trail were not suitable for the major organic pollutants exist in the site Soil in this project.
-
time dependent performance of Soil Mix technology mass stabilised contaminated site Soils
7th International Congress on Environmental Geotechnics : iceg2014, 2014Co-Authors: Fei Wang, Abir AltabbaaAbstract:Soil Mixing Technology (SMT) has emerged as a cost-effective, efficient, versatile, and low risk method for the implementation of a range of in-situ remediation treatments. However, contaminants remain in the ground following SMT, and hence assessment of the time-dependent performance of real projects is essential for the validation of the technology and its wider acceptability amongst stakeholders. The SMT system considered in this paper is mass stabilisation, using the ALLU system, which is an effective technique for combining contaminated Soil remediation and ground improvement treatments on the same site. Field trial samples were obtained from the Soil Mix Remediation Technology (SMiRT) project site which contains both heavy metals and organic contaminants. The purpose of this study was to investigate the effect of different combinations of various binders and dosages on physical, strength and leachability behaviour of the mass stabilised Soils at 1 year after treatment. The binder dosages used were 2.5, 5, and 10% by weight. Samples of the treated Soils were subjected to unconfined compressive strength (UCS) and BS EN 12457 batch leaching test at 40 days and 1 year after treatment. The results show that 1) the strength of the mass stabilised site made ground increased with time; 2) the combination of GGBS:MgO at a ratio of 9:1 has the best strength and leachability performances amongst all Mixes; 3) the leachability of Pb, Cu and Zn meet the drinking water standards; and 4) the leachability of total organics varied for the different Mixes.