Saeed Safaei, Seyed Ahmad Mirbagheri, M. Ehteshami, E. Teymouri, M. Salari
In the present study, oxytetracycline (OTC) was selected as a medical contaminant with an organic structure to increase the efficiency and feasibility of comparison with other research studies. Therefore, the removal of OTC from medicinal effluents using different methods; namely, activated carbon, bentonite adsorption, iron(III) chloride coagulation, membrane filtration and reverse osmosis (RO), was investigated. Results indicated that the removal of soluble antibiotics in the factory wastewater by adsorption method was between 35% and 77%, at a pH of 6.5 and the total dissolved solids (TDS) and OTC concentration were reduced by 55% and 77%, respectively. In the coagulation method, where the suitable pH ranges from 5.5 to and 7.5, the optimal dosage of iron (III) chloride coagulation was between 40 and 100 mg/l, which resulted in 98.7% of OTC removal. It was concluded that the highest OTC adsorption of 98.7% in the RO membrane and TDS removal were obtained at a pressure of 9 bars. All the experiments on these membranes were performed within 4 months and the membranes still performed well. Therefore, it is concluded that long-term operation has little effect on the performance of the membrane and this membrane is a suitable membrane for the concentration of OTC. Finally, the RO is defined as the suitable method for OTC removal, after passing once through the membrane, while the other methods are proper to be used in the pre-treatment of medicinal wastewater. KEYWORDS: Antibiotics, Absorption, Coagulation, Membrane filtration, Reverse osmosis.
{"title":"Removal of Antibiotics from Wastewater by Comparison of Coagulation, Membrane and Adsorption Methods","authors":"Saeed Safaei, Seyed Ahmad Mirbagheri, M. Ehteshami, E. Teymouri, M. Salari","doi":"10.14525/jjce.v17i3.10","DOIUrl":"https://doi.org/10.14525/jjce.v17i3.10","url":null,"abstract":"In the present study, oxytetracycline (OTC) was selected as a medical contaminant with an organic structure to increase the efficiency and feasibility of comparison with other research studies. Therefore, the removal of OTC from medicinal effluents using different methods; namely, activated carbon, bentonite adsorption, iron(III) chloride coagulation, membrane filtration and reverse osmosis (RO), was investigated. Results indicated that the removal of soluble antibiotics in the factory wastewater by adsorption method was between 35% and 77%, at a pH of 6.5 and the total dissolved solids (TDS) and OTC concentration were reduced by 55% and 77%, respectively. In the coagulation method, where the suitable pH ranges from 5.5 to and 7.5, the optimal dosage of iron (III) chloride coagulation was between 40 and 100 mg/l, which resulted in 98.7% of OTC removal. It was concluded that the highest OTC adsorption of 98.7% in the RO membrane and TDS removal were obtained at a pressure of 9 bars. All the experiments on these membranes were performed within 4 months and the membranes still performed well. Therefore, it is concluded that long-term operation has little effect on the performance of the membrane and this membrane is a suitable membrane for the concentration of OTC. Finally, the RO is defined as the suitable method for OTC removal, after passing once through the membrane, while the other methods are proper to be used in the pre-treatment of medicinal wastewater. KEYWORDS: Antibiotics, Absorption, Coagulation, Membrane filtration, Reverse osmosis.","PeriodicalId":51814,"journal":{"name":"Jordan Journal of Civil Engineering","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43177803","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Stilling basins are designed to reduce the high kinetic energy of supercritical flow in a downstream spillway. The USBR II stilling basin is distinguished by chute blocks fixed at the upstream end and a dented sill at the downstream end, allowing for the effective dissipation of excess energy. This research investigates the effect of chute-block geometry on the hydraulic performance of the USBR II stilling basin. Six modified chute-blocks with identical dimensions and spacings as standard blocks were constructed and evaluated for six incoming Froude-number values. The results indicate that chute blocks containing stepped side walls are more effective than standard blocks, increasing energy dissipation by 1.47% and decreasing the sequent depth ratio by 3.91%. Blocks with gradually increased spacings lose 0.7% more energy than standard blocks and reduce the sequential depth ratio by 1.91%. However, blocks with prismatic spacings and top surface angles of 152 degrees, relative to the downstream slope of the spillway, are less effective than standard blocks with energy dissipation reduced by 2.73% and the depth ratio increased by 7.24%.
{"title":"Effects of Chute Block Geometry on the Performance of the USBR II Stilling Basin","authors":"Layla Ali Mohammed Saleh, Saleh Issa Khassaf","doi":"10.14525/jjce.v17i3.12","DOIUrl":"https://doi.org/10.14525/jjce.v17i3.12","url":null,"abstract":"Stilling basins are designed to reduce the high kinetic energy of supercritical flow in a downstream spillway. The USBR II stilling basin is distinguished by chute blocks fixed at the upstream end and a dented sill at the downstream end, allowing for the effective dissipation of excess energy. This research investigates the effect of chute-block geometry on the hydraulic performance of the USBR II stilling basin. Six modified chute-blocks with identical dimensions and spacings as standard blocks were constructed and evaluated for six incoming Froude-number values. The results indicate that chute blocks containing stepped side walls are more effective than standard blocks, increasing energy dissipation by 1.47% and decreasing the sequent depth ratio by 3.91%. Blocks with gradually increased spacings lose 0.7% more energy than standard blocks and reduce the sequential depth ratio by 1.91%. However, blocks with prismatic spacings and top surface angles of 152 degrees, relative to the downstream slope of the spillway, are less effective than standard blocks with energy dissipation reduced by 2.73% and the depth ratio increased by 7.24%.","PeriodicalId":51814,"journal":{"name":"Jordan Journal of Civil Engineering","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46656558","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The energy demand is set to grow very rapidly and the potential demand for oil around the world is at its highest level. Apart from indigenous oil sources, crude oil is imported by water transportation to fulfill local demand. The occurrence of oil leakage during drilling and transportation in pipelines is a major concern. As a result of this, soil is getting polluted and its geotechnical properties are altered. In this study, the effect of engine oil and diesel contamination on the geotechnical parameters of sea sand has been studied. Further, to enhance the properties of oil-contaminated sand, the bioremediation method was adopted. Sea sand from Ganagalla Peta beach, Andhra Pradesh state, India was taken up for the study. In the laboratory, 4%, 8%, 12% and 16% of engine oil and diesel were used to artificially contaminate the sea sand and geotechnical parameters; namely, compaction, shear strength and permeability, were studied for oil-contaminated sand and compared with those of virgin sea sand. In the next stage, bioremediation of engine oil-and diesel-contaminated sand was carried out to improve the geotechnical properties. It has been found that the geotechnical properties had improved after three days of bioremediation. Fourier transform infrared spectroscopy (FTIR) analysis showed that the contaminated sand is of a lipopeptide nature and showed the presence of carboxyl groups, whereas the IR absorption pattern of the treated sand matches with N-Methyl-N-Vinyl Acetamide. KEYWORDS: Engine-oil contamination, Diesel contamination, Bioremediation, Bacillus subtilis, Geotechnical properties, Compaction characteristics, Shear-strength characteristics, Permeability, FTIR analysis.
能源需求将快速增长，全球对石油的潜在需求正处于最高水平。除本地石油来源外，原油通过水运进口以满足当地需求。在钻井和管道运输过程中，石油泄漏的发生一直是人们关注的焦点。因此，土壤受到污染，其岩土力学特性被改变。本文研究了发动机机油和柴油污染对海砂岩土参数的影响。为了提高油砂的性能，采用了生物修复的方法。印度安得拉邦Ganagalla Peta海滩的海砂被用于研究。在实验室中，分别使用4%、8%、12%和16%的机油和柴油对海砂和岩土参数进行人工污染;研究了含油污染砂的压实、抗剪强度和渗透性，并与原始海砂进行了比较。下一步，对机油和柴油污染砂进行生物修复，以改善其岩土性能。经过3天的生物修复，土工性能得到了改善。傅里叶变换红外光谱(FTIR)分析表明，污染砂具有脂肽性质，并存在羧基，而处理砂的红外吸收模式与n -甲基- n -乙烯基乙酰胺相匹配。关键词:机油污染，柴油污染，生物修复，枯草芽孢杆菌，岩土力学特性，压实特性，抗剪强度特性，渗透性，FTIR分析
{"title":"Bioremediation of Oil-contaminated Sand","authors":"S. Sathyapriya, R. Sharvesh, C. Natarajan","doi":"10.14525/jjce.v17i3.05","DOIUrl":"https://doi.org/10.14525/jjce.v17i3.05","url":null,"abstract":"The energy demand is set to grow very rapidly and the potential demand for oil around the world is at its highest level. Apart from indigenous oil sources, crude oil is imported by water transportation to fulfill local demand. The occurrence of oil leakage during drilling and transportation in pipelines is a major concern. As a result of this, soil is getting polluted and its geotechnical properties are altered. In this study, the effect of engine oil and diesel contamination on the geotechnical parameters of sea sand has been studied. Further, to enhance the properties of oil-contaminated sand, the bioremediation method was adopted. Sea sand from Ganagalla Peta beach, Andhra Pradesh state, India was taken up for the study. In the laboratory, 4%, 8%, 12% and 16% of engine oil and diesel were used to artificially contaminate the sea sand and geotechnical parameters; namely, compaction, shear strength and permeability, were studied for oil-contaminated sand and compared with those of virgin sea sand. In the next stage, bioremediation of engine oil-and diesel-contaminated sand was carried out to improve the geotechnical properties. It has been found that the geotechnical properties had improved after three days of bioremediation. Fourier transform infrared spectroscopy (FTIR) analysis showed that the contaminated sand is of a lipopeptide nature and showed the presence of carboxyl groups, whereas the IR absorption pattern of the treated sand matches with N-Methyl-N-Vinyl Acetamide. KEYWORDS: Engine-oil contamination, Diesel contamination, Bioremediation, Bacillus subtilis, Geotechnical properties, Compaction characteristics, Shear-strength characteristics, Permeability, FTIR analysis.","PeriodicalId":51814,"journal":{"name":"Jordan Journal of Civil Engineering","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47247580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In recent years, Lebanon has been grappling with a multitude of crises across all sectors, presenting numerous challenges that have hindered the progress of the construction industry. The construction industry in Lebanon is plagued by a complex array of risks that can lead to the downfall of construction projects. Therefore, this study is primarily concerned with identifying the most crucial economic and time risk factors influencing the Lebanese construction projects. To achieve the research aim, a questionnaire was initially developed from a review of various sources of literature and then refined to reflect the unique circumstances faced by Lebanon in recent years. In addition to that, some interviews to analyze the economic and time risk factors were conducted among expert respondents in the Lebanese construction industry. Then, the relative important index (RII) was applied in order to classify the major risk factors. The findings obtained from the study reveal that currency fluctuation, risk of war, geological risks, risk of pandemics and vendor failures are the most crucial risk factors that influence the time and cost of the Lebanese construction projects. Finally, in order to mitigate the occurrence of the most critical risk factors identified in this study and ensure successful construction projects in Lebanon, effective risk-management strategies should be implemented. KEYWORDS: Risk factors, Construction projects, Cost, Time, Lebanon.
{"title":"Economic and Time Risk Factors Influencing the Construction Projects: A Case Study of Lebanese Construction Projects","authors":"O. Ahmad, Fatemeh Nouban","doi":"10.14525/jjce.v17i3.03","DOIUrl":"https://doi.org/10.14525/jjce.v17i3.03","url":null,"abstract":"In recent years, Lebanon has been grappling with a multitude of crises across all sectors, presenting numerous challenges that have hindered the progress of the construction industry. The construction industry in Lebanon is plagued by a complex array of risks that can lead to the downfall of construction projects. Therefore, this study is primarily concerned with identifying the most crucial economic and time risk factors influencing the Lebanese construction projects. To achieve the research aim, a questionnaire was initially developed from a review of various sources of literature and then refined to reflect the unique circumstances faced by Lebanon in recent years. In addition to that, some interviews to analyze the economic and time risk factors were conducted among expert respondents in the Lebanese construction industry. Then, the relative important index (RII) was applied in order to classify the major risk factors. The findings obtained from the study reveal that currency fluctuation, risk of war, geological risks, risk of pandemics and vendor failures are the most crucial risk factors that influence the time and cost of the Lebanese construction projects. Finally, in order to mitigate the occurrence of the most critical risk factors identified in this study and ensure successful construction projects in Lebanon, effective risk-management strategies should be implemented. KEYWORDS: Risk factors, Construction projects, Cost, Time, Lebanon.","PeriodicalId":51814,"journal":{"name":"Jordan Journal of Civil Engineering","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46392484","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study proposes recycling waste clay brick and waste polyethylene terephthalate (PET) bottles as substitution materials in geopolymer concrete. To accomplish this goal, the control mix of geopolymer concrete was prepared based on blended metakaolin and waste clay brick powder (CBP) at a 1:1 mixture by weight. To evaluate the use of shredded PET particles as fine aggregate, three mixtures were made by replacing sand with PET aggregate at volumetric percentages (10%, 15% and 20%). The specimens containing PET aggregate were tested and compared against the control mix (0% PET), with emphasis on the fresh and dry densities, mechanical performance, water absorption and microstructure characteristics. The results indicated the inclusion of PET aggregate to slightly reduce density and improve mechanical properties. When compared to the control mix, the compressive strength of the 20% PET replacement increased to 28.1 MPa after 28 days. Moreover, the concrete with 20% PET obtained the lowest water-absorption rate. The scanning electron microscopy images revealed that the inclusion of waste PET as sand had a significant effect on the microstructure of Mk-CBP geopolymer concrete. When compared to the control mix, the matrix containing 20% PET had a denser microstructure, as well as fewer holes and microcracks, in addition to the packing of paste at the interfacial transition zone. KEYWORDS: Brick powder, Fine aggregate, Geopolymer concrete, Metakaolin, Polyethylene terephthalate (PET).
{"title":"Effective Use of Waste Plastic As Sand in Metakaolin/Brick-Powder Geopolymer Concrete","authors":"Mahmood Fawzi Ahmed","doi":"10.14525/jjce.v17i3.09","DOIUrl":"https://doi.org/10.14525/jjce.v17i3.09","url":null,"abstract":"This study proposes recycling waste clay brick and waste polyethylene terephthalate (PET) bottles as substitution materials in geopolymer concrete. To accomplish this goal, the control mix of geopolymer concrete was prepared based on blended metakaolin and waste clay brick powder (CBP) at a 1:1 mixture by weight. To evaluate the use of shredded PET particles as fine aggregate, three mixtures were made by replacing sand with PET aggregate at volumetric percentages (10%, 15% and 20%). The specimens containing PET aggregate were tested and compared against the control mix (0% PET), with emphasis on the fresh and dry densities, mechanical performance, water absorption and microstructure characteristics. The results indicated the inclusion of PET aggregate to slightly reduce density and improve mechanical properties. When compared to the control mix, the compressive strength of the 20% PET replacement increased to 28.1 MPa after 28 days. Moreover, the concrete with 20% PET obtained the lowest water-absorption rate. The scanning electron microscopy images revealed that the inclusion of waste PET as sand had a significant effect on the microstructure of Mk-CBP geopolymer concrete. When compared to the control mix, the matrix containing 20% PET had a denser microstructure, as well as fewer holes and microcracks, in addition to the packing of paste at the interfacial transition zone. KEYWORDS: Brick powder, Fine aggregate, Geopolymer concrete, Metakaolin, Polyethylene terephthalate (PET).","PeriodicalId":51814,"journal":{"name":"Jordan Journal of Civil Engineering","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48314820","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Incorporating waste stone powders into the production of reactive powder concretes (RPCs) can be eco-friendly. Since high cementitious material content is used in producing RPCs, CO2, as a harmful greenhouse gas, was used for carbonation curing in this study. For this purpose, waste limestone powder was substituted by 0%, 18%, 36% and 54% of silica sand and the specimens were cured in water for up to 90 days in a CO2 chamber for up to 48 hours. The physical and mechanical properties of the concrete and the specimens' CO2 uptake were measured at different ages. Results showed that the 28-day compressive strength of the moist cured RPCs was higher than 100 MPa and the properties of the RPCs were improved by increasing limestone substitution. CO2 curing of the RPCs significantly increased the samples' compressive strength and limestone-powder substitution as silica sand significantly decreased the carbonation and autogenous shrinkages of the RPCs. Moreover, carbonation curing can make eco-friendly limestone-modified RPCs, where their properties are improved. KEYWORDS: CO2 curing, Reactive powder concrete, Waste limestone powder, Shrinkage.
{"title":"CO2 Curing of Reactive Powder Concretes Modified by Waste Limestone Powder","authors":"H. Rahmani, Nooshin Mohammadzade","doi":"10.14525/jjce.v17i3.08","DOIUrl":"https://doi.org/10.14525/jjce.v17i3.08","url":null,"abstract":"Incorporating waste stone powders into the production of reactive powder concretes (RPCs) can be eco-friendly. Since high cementitious material content is used in producing RPCs, CO2, as a harmful greenhouse gas, was used for carbonation curing in this study. For this purpose, waste limestone powder was substituted by 0%, 18%, 36% and 54% of silica sand and the specimens were cured in water for up to 90 days in a CO2 chamber for up to 48 hours. The physical and mechanical properties of the concrete and the specimens' CO2 uptake were measured at different ages. Results showed that the 28-day compressive strength of the moist cured RPCs was higher than 100 MPa and the properties of the RPCs were improved by increasing limestone substitution. CO2 curing of the RPCs significantly increased the samples' compressive strength and limestone-powder substitution as silica sand significantly decreased the carbonation and autogenous shrinkages of the RPCs. Moreover, carbonation curing can make eco-friendly limestone-modified RPCs, where their properties are improved. KEYWORDS: CO2 curing, Reactive powder concrete, Waste limestone powder, Shrinkage.","PeriodicalId":51814,"journal":{"name":"Jordan Journal of Civil Engineering","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42042503","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shadman Rahman Sabab, H. Md. Shahin, Muftashin Muhim Bondhon, Md. Ehsan Kabir
This study focuses on establishing a robust relationship between Standard Penetration Test-N values (SPT-N), geotechnical parameters and unconfined compressive strength (qu) using regression analysis. The proposed relationship offers a reliable method for estimating qu based on SPT-N values. A comprehensive dataset comprising approximately 200 soil samples collected from various boreholes across Dhaka city was utilized. Multiple Linear Regression (MLR), Rando-forest Regression (RFR) and AdaBoost Regression techniques were employed to develop a unified correlation model. Evaluation metrics including R-squared (R2), Mean Absolute Error (MAE) and Root Mean Squared Error (RMSE), along with Trend-behavior Analysis were employed to assess and compare the performances of the models. Additionally, sensitivity analysis was carried out on the selected model in order to assess the importance of each parameter used to predict qu. Finally, the selected model was compared against the existing empirical models that were published in previous studies. In terms of evaluation metrics and Trend-behavior Analysis, the results showed that the RFR model performed better than the others. Additionally, the selected model outperformed the others, demonstrating the highest R2 score, the smallest RMSE and MAE values and lower residuals compared to the previous models. Hence, the proposed model provides accurate predictions of qu for clayey soil in Bangladesh. Its implementation could ensure more efficient geotechnical designs, specifically adjusted to the geological conditions of the Dhaka region. While previous studies have established regional equations for various parts of the world, our model uniquely has incorporated the Plasticity Index (PI) as a predictor for qu and is specifically calibrated for the geological characteristics of Dhaka city. The findings of this study highlight the effectiveness and applicability of regression analysis in predicting qu for Dhaka's soil properties, thus introducing a valuable tool for enhancing the accuracy and effectiveness of geotechnical assessments and design in the region. KEYWORDS: Unconfined compressive strength, Standard penetration test-N values, Plasticity index, Multiple linear regression, Random-forest regression, AdaBoost regression, Evaluation metrics, Trend-behavior analysis, Sensitivity analysis
{"title":"Regression Analysis for Predicting Soil Strength in Bangladesh","authors":"Shadman Rahman Sabab, H. Md. Shahin, Muftashin Muhim Bondhon, Md. Ehsan Kabir","doi":"10.14525/jjce.v17i3.14","DOIUrl":"https://doi.org/10.14525/jjce.v17i3.14","url":null,"abstract":"This study focuses on establishing a robust relationship between Standard Penetration Test-N values (SPT-N), geotechnical parameters and unconfined compressive strength (qu) using regression analysis. The proposed relationship offers a reliable method for estimating qu based on SPT-N values. A comprehensive dataset comprising approximately 200 soil samples collected from various boreholes across Dhaka city was utilized. Multiple Linear Regression (MLR), Rando-forest Regression (RFR) and AdaBoost Regression techniques were employed to develop a unified correlation model. Evaluation metrics including R-squared (R2), Mean Absolute Error (MAE) and Root Mean Squared Error (RMSE), along with Trend-behavior Analysis were employed to assess and compare the performances of the models. Additionally, sensitivity analysis was carried out on the selected model in order to assess the importance of each parameter used to predict qu. Finally, the selected model was compared against the existing empirical models that were published in previous studies. In terms of evaluation metrics and Trend-behavior Analysis, the results showed that the RFR model performed better than the others. Additionally, the selected model outperformed the others, demonstrating the highest R2 score, the smallest RMSE and MAE values and lower residuals compared to the previous models. Hence, the proposed model provides accurate predictions of qu for clayey soil in Bangladesh. Its implementation could ensure more efficient geotechnical designs, specifically adjusted to the geological conditions of the Dhaka region. While previous studies have established regional equations for various parts of the world, our model uniquely has incorporated the Plasticity Index (PI) as a predictor for qu and is specifically calibrated for the geological characteristics of Dhaka city. The findings of this study highlight the effectiveness and applicability of regression analysis in predicting qu for Dhaka's soil properties, thus introducing a valuable tool for enhancing the accuracy and effectiveness of geotechnical assessments and design in the region. KEYWORDS: Unconfined compressive strength, Standard penetration test-N values, Plasticity index, Multiple linear regression, Random-forest regression, AdaBoost regression, Evaluation metrics, Trend-behavior analysis, Sensitivity analysis","PeriodicalId":51814,"journal":{"name":"Jordan Journal of Civil Engineering","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46120840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Syrian construction industry is plagued with risks that can be challenging to the overall success of any construction project. To minimize a project’s damage in terms of cost, time and quality, an authentic data-driven and expert-approved risk plan must be developed. This paper proposes a methodology to identify and assess major risks based on the personal evaluation of experienced civil engineers as a step in a comprehensive risk-management process. By combining a ranked risk magnitude index and an assigned risk zone, fifteen major risks were identified and assessed. Companies are advised to use the list to develop a resourceful general risk plan. Combining the two methods together makes the risk plan more representative and thus more reliable, as the two proposed methods can result in different rankings. The top fifteen risks in the Syrian construction industry were mainly management, financial and design risks. Locating in the zone of maximum risk came “an unprecedented increase in raw-material prices” and “the loss due to an increase in fuel prices” as number one and number two, respectively”. “Unavailability of resources” was next in the zone of high risk. “Improper cost estimation” and “losing critical work forces at a critical time” scored high in the final ranking. KEYWORDS: Risk identification, Risk assessment, Syria, Construction industry.
{"title":"Identification and Assessment of Major Risks in Syrian Construction Projects: Lattakia-Syria Case","authors":"Reem Ghanem Kattoub, J. Omran","doi":"10.14525/jjce.v17i3.13","DOIUrl":"https://doi.org/10.14525/jjce.v17i3.13","url":null,"abstract":"The Syrian construction industry is plagued with risks that can be challenging to the overall success of any construction project. To minimize a project’s damage in terms of cost, time and quality, an authentic data-driven and expert-approved risk plan must be developed. This paper proposes a methodology to identify and assess major risks based on the personal evaluation of experienced civil engineers as a step in a comprehensive risk-management process. By combining a ranked risk magnitude index and an assigned risk zone, fifteen major risks were identified and assessed. Companies are advised to use the list to develop a resourceful general risk plan. Combining the two methods together makes the risk plan more representative and thus more reliable, as the two proposed methods can result in different rankings. The top fifteen risks in the Syrian construction industry were mainly management, financial and design risks. Locating in the zone of maximum risk came “an unprecedented increase in raw-material prices” and “the loss due to an increase in fuel prices” as number one and number two, respectively”. “Unavailability of resources” was next in the zone of high risk. “Improper cost estimation” and “losing critical work forces at a critical time” scored high in the final ranking. KEYWORDS: Risk identification, Risk assessment, Syria, Construction industry.","PeriodicalId":51814,"journal":{"name":"Jordan Journal of Civil Engineering","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47430651","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Excavation of tunnels or chambers causes crack initiation, propagation and coalescence, resulting in the instability and destruction of underground projects. Understanding the damage mechanism of joint rock-like materials is important for maintaining the stability of concrete construction. Based on the Mohr–Coulomb criterion and Lemaitre strain equivalence hypothesis, the coupling-damage constitutive model of rock masses was improved for application to plain concrete. Parameters including the mesoscopic and macro-meso coupling damage variables, as well as the fractal dimension, were calculated to realize the non-linear mechanical behaviour during damage evolution. The rationality of the model was verified by comparing experimental and theoretical parameters. Results revealed that the coupled-damage constitutive model of rock masses has a good applicability to plain concrete. Furthermore, two main factors affected the damage deformation: the number of joints and the inclination angle. As the number of joints increased, the early damage accumulation increased and the inflection point of the damage rate occurred in advance. The damage deformation varied significantly when the inclination angle was changed. The cumulative damage curve of the plain-concrete specimens is shown as the evolution law of an S-type curve. Both peak strength and elastic modulus were positively correlated with the damage variable. Moreover, a smaller peak strength resulted in a larger fractal dimension and coupling-damage variable. KEYWORDS: Rock mass, Joint inclination angle, Mesoscopic, Macroscopic, Fractal dimension, Coupling-damage constitutive model.
{"title":"Damage Mechanism on Different Joint Types of Plain Concrete under Uniaxial Compression","authors":"Shanshan Guo, D. Cui, Liang Lv","doi":"10.14525/jjce.v17i2.14","DOIUrl":"https://doi.org/10.14525/jjce.v17i2.14","url":null,"abstract":"Excavation of tunnels or chambers causes crack initiation, propagation and coalescence, resulting in the instability and destruction of underground projects. Understanding the damage mechanism of joint rock-like materials is important for maintaining the stability of concrete construction. Based on the Mohr–Coulomb criterion and Lemaitre strain equivalence hypothesis, the coupling-damage constitutive model of rock masses was improved for application to plain concrete. Parameters including the mesoscopic and macro-meso coupling damage variables, as well as the fractal dimension, were calculated to realize the non-linear mechanical behaviour during damage evolution. The rationality of the model was verified by comparing experimental and theoretical parameters. Results revealed that the coupled-damage constitutive model of rock masses has a good applicability to plain concrete. Furthermore, two main factors affected the damage deformation: the number of joints and the inclination angle. As the number of joints increased, the early damage accumulation increased and the inflection point of the damage rate occurred in advance. The damage deformation varied significantly when the inclination angle was changed. The cumulative damage curve of the plain-concrete specimens is shown as the evolution law of an S-type curve. Both peak strength and elastic modulus were positively correlated with the damage variable. Moreover, a smaller peak strength resulted in a larger fractal dimension and coupling-damage variable. KEYWORDS: Rock mass, Joint inclination angle, Mesoscopic, Macroscopic, Fractal dimension, Coupling-damage constitutive model.","PeriodicalId":51814,"journal":{"name":"Jordan Journal of Civil Engineering","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47986686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This research aims to investigate the use of magnetic iron nano-particles (FeN) for the removal of heavy metals under single and ternary scenarios. The methodology includes synthesis of FeN using chemical precipitation approach, batch experiments for single and ternary metals removal, isotherm and kinetic studies, thermos-dynamic study and assessing the effect of different parameters on the adsorption process. The results showed that the maximum removal for As and Hg was achieved at a pH of 7, while a pH of 6 provided a slightly higher removal of Cd than a pH of 7 at an optimum mixing time of 120 minutes. The optimum adsorption capacities of As, Cd and Hg at the initial concentration of 200 ppm were 260, 280 and 75.0 mg/g in the case of single metal removal against 91.5, 237.8 and 341.5 mg/g in the case of ternary combination, respectively. The removal of all metals increased with increasing the FeN dose and the mixing time, while it decreased with the increase of the initial concentration. The removal efficiency was affected strongly by the presence of multiple metals, while As removal decreased sharply and Hg removal increased significantly. Adsorption selectivity is affected negatively by the increase in atomic weight and atomic radius. In the case of single-metal removal, fitting of isotherm models can be ranked as Langmuir>Freundlich>Temkin>D-R for As and Cd and Temkin>Freundlich>D-R>Langmuir for Hg, while contradictory results were obtained in the case of ternary combination. Kinetic studies found that the adsorption follows the pseudo-second-order model with R2=0.99. For all metals, the adsorption process is highly favourable at higher temperatures and is endothermic in nature with (ΔHo) of 10.91, 23.86 and 0.163 for As, Cd and Hg, respectively. Coating of FeN with silica resulted in lower removal efficiency for all metals up to 50%. It can be concluded that FeN can be successfully used for the removal of heavy metals either through the single or ternary approach, but the single approach provides a higher performance. KEYWORDS: Nano-materials, Magnetite iron, Adsorption, Arsenic, Cadmium, Mercury, Lead.
{"title":"Single and Ternary Removal of Heavy Metals from Aqueous Solution Using Fe3O4 Magnetic Nano-particles","authors":"K. Al-Zboon","doi":"10.14525/jjce.v17i2.13","DOIUrl":"https://doi.org/10.14525/jjce.v17i2.13","url":null,"abstract":"This research aims to investigate the use of magnetic iron nano-particles (FeN) for the removal of heavy metals under single and ternary scenarios. The methodology includes synthesis of FeN using chemical precipitation approach, batch experiments for single and ternary metals removal, isotherm and kinetic studies, thermos-dynamic study and assessing the effect of different parameters on the adsorption process. The results showed that the maximum removal for As and Hg was achieved at a pH of 7, while a pH of 6 provided a slightly higher removal of Cd than a pH of 7 at an optimum mixing time of 120 minutes. The optimum adsorption capacities of As, Cd and Hg at the initial concentration of 200 ppm were 260, 280 and 75.0 mg/g in the case of single metal removal against 91.5, 237.8 and 341.5 mg/g in the case of ternary combination, respectively. The removal of all metals increased with increasing the FeN dose and the mixing time, while it decreased with the increase of the initial concentration. The removal efficiency was affected strongly by the presence of multiple metals, while As removal decreased sharply and Hg removal increased significantly. Adsorption selectivity is affected negatively by the increase in atomic weight and atomic radius. In the case of single-metal removal, fitting of isotherm models can be ranked as Langmuir>Freundlich>Temkin>D-R for As and Cd and Temkin>Freundlich>D-R>Langmuir for Hg, while contradictory results were obtained in the case of ternary combination. Kinetic studies found that the adsorption follows the pseudo-second-order model with R2=0.99. For all metals, the adsorption process is highly favourable at higher temperatures and is endothermic in nature with (ΔHo) of 10.91, 23.86 and 0.163 for As, Cd and Hg, respectively. Coating of FeN with silica resulted in lower removal efficiency for all metals up to 50%. It can be concluded that FeN can be successfully used for the removal of heavy metals either through the single or ternary approach, but the single approach provides a higher performance. KEYWORDS: Nano-materials, Magnetite iron, Adsorption, Arsenic, Cadmium, Mercury, Lead.","PeriodicalId":51814,"journal":{"name":"Jordan Journal of Civil Engineering","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46463622","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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