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construction Research Congress 2024, CRC 2024

作者： Hajiashrafi, Fatemeh Huynh, Huu T. Lucko, Gunnar Eid, Mohamed S. Construction Engineering and Management Program Dept. of Civil and Environmental Engineering Catholic Univ. of America WashingtonDC United States Dept. of Civil and Environmental Engineering Catholic Univ. of America WashingtonDC United States Dept. of Construction and Building Engineering College of Engineering and Technology Arab Academy for Science Technology and Maritime Transport Cairo Egypt

ISBN: (数字)9780784485286

ISBN: (纸本)9780784485286

Despite various attempts throughout past decades to deal with concurrent delays in construction project schedules, they continue to be a vexing issue that has eluded an unambiguous solution. Prior studies have resorted to the prime contract, which only binds general contractor and owner, cannot be proven to be fair, and may even be biased. Therefore, this paper adopts a concept from cooperative game theory, the Shapley value, which apportions profits (which project participants seek to maximize). Creatively applying it to liquidated damages (which they seek to minimize), the model uses all participants' actual finish dates as input to gain percentage shares of liquidated damages as output. Analyzing all possible coalitions among participants and assigning weights comprehensively assesses their marginal contributions to the project finish date. This generalized view of participants explicitly includes subcontractors, whom prior approaches typically ignored. An example demonstrates how the model also implies an early completion bonus. This yields compelling implications for real-world incentives that can be cast into future contract clauses. © ASCE.

关键词： Contractors

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Influence of rice husk ash and hybrid fiber on engineering properties of densified high-performance fiber-reinforced concrete

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Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 2023年第11期237卷 2845-2857页

作者： Vo, Duy-Hai Nguyen, Minh-Hieu Nguyen, May Huu Hwang, Chao-Lung Huynh, Trong-Phuoc The University of Danang University of Technology and Education Danang Viet Nam Vinh Long Department of Construction Vinh Long Viet Nam Civil and Environmental Engineering Program Graduate School of Advanced Science and Engineering Hiroshima University Hiroshima Japan Department of Bridge and Tunnel Faculty of Civil Engineering University of Transport Technology Hanoi Viet Nam Taiwan Building Technology Center National Taiwan University of Science and Technology Taipei Taiwan Faculty of Civil Engineering College of Engineering Can Tho University Can Tho Viet Nam

Conventional concrete significantly affects the environment due to high CO2 emission into the atmosphere during the production process. In order to improve concrete performance and arrest the incidence of global warming, the use of additive materials for cement replacement has been promoted worldwide. This study was designed to investigate the mechanical properties of high-performance fiber-reinforced concrete (HFRC) produced using rice husk ash (RHA) and hybrid fiber (HF) in accordance with the densified mixture design algorithm (DMDA) mix design method. Samples were produced using RHA as a direct replacement for cement at 10%, 20%, and 30%. HF, comprising steel and polypropylene fibers, was added (by volume) to the 20% RHA group mixture to improve the HFRC sample properties. Based on the experimental results, higher RHA contents had a generally negative effect on the fresh properties of the HFRC mixtures. Compressive strength values ranged from 53 to 72 MPa with various RHA and HF content. RHA replacement levels up to 20% had an insignificant effect on the strength development and dynamic modulus of the HFRC samples. However, the addition of HF improved splitting tensile strength, flexural strength, and dynamic modulus remarkably at all curing ages. Furthermore, the 91-day drying shrinkage was in the ranges of 0.032%–0.039% and 0.023%–0.034% using different RHA and HF levels, respectively. Increasing both RHA and HF contents significantly reduced drying shrinkage in the samples. Multivariable regression was also performed, clarifying that all tested results were consistent and had good correlations. The results of this study also provide a potentially effective use for abundantly available industrial waste products such as fly ash (FA) and RHA to promote the production of greener and more sustainable concrete. © IMechE 2023.

关键词： Bending strength

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Perceptions and Pedagogical Responses of construction Educators During COVID-19

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International Journal of construction Education and Research 2023年第4期19卷 405-425页

作者： Langar, Sandeep Mosier, Rachel Adhikari, Sanjeev School of Civil and Environmental Engineering and Construction Management The University of Texas at San Antonio San Antonio TX United States Francis and Kathleen Rooney Construction Engineering Technology Program Oklahoma State University Stillwater OK United States Department of Construction Management Kennesaw State University Atlanta GA United States

COVID-19 impacted academia across the globe. Given the scale and sudden pandemic onset, limited empirical studies identify the transition’s impact on the US construction educators and education imparted. The study determined the pedagogical responses of educators associated with construction programs within the US during COVID-19 and tested six relationships in the areas of university support, technological access and infrastructure, and educator proficiency improvements. An online survey method was utilized with the instrument emailed to nearly 1,883 educators associated with construction programs/departments across the US. The study used 163 complete responses from US educators based on predefined parameters and identified the baseline operational paradigm (pre-COVID) for construction educators and programs across the US. The study determined the changes after the transition and investigated the impacts of the transition on faculty proficiency with online teaching, existing technological infrastructure, and communication with students. The study identified a moderate relationship between the University’s level of support and educators’ experiences in developing and delivering online materials during the transition. A moderate relationship was also identified between proficiency with online content delivery and total teaching experience. Finally, only a few respondents felt construction education could be delivered entirely online, based on their experiences. © 2022 Associated Schools of construction.

关键词： construction educators COVID-19 impacts on academia online education pedagogical responses to COVID-19

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Flood Management Strategies in Indonesia: A Lesson Learned from Pepe River, Central Java 5th

Flood Management Strategies in Indonesia: A Lesson Learned f...

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5th International Conference on Rehabilitation and Maintenance in civil engineering, ICRMCE 2021

作者： Prastica, Rian Mantasa Salve Wijayanti, Amalia Civil Engineering Department Gadjah Mada University Yogyakarta55281 Indonesia Water Infrastructure Construction Technology Study Program Public Works Polytechnic Semarang50275 Indonesia

ISBN: (纸本)9789811693472

Floods occur every year and threaten communities worldwide. Indonesia is among the countries faced with this problem and still struggling to seek practical solutions to date. Further, as the country’s centers of trade, business, and technology, the island of Java cannot even perform better in dealing with floods. To further understand possible damage and losses, this research investigated structural mitigation measures as part of flood management in the Pepe River, notably river channelization to increase hydraulic efficiency. For the analysis, it used HEC-RAS to observe the river capacity. Existing conditions revealed that the river could not accommodate the predicted floods based on the return periods derived from the synthetic unit hydrograph of Nakayasu. However, after running the mitigation scenario wherein hydraulic modification was applied, flood risk could be reduced by lowering the river water level. Based on the results, it can be concluded that Indonesia needs to pay more attention to other aspects: ecology, green infrastructure, and water governance, to achieve more effective flood mitigation measures because structural mitigation only provides a temporary solution. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

关键词： Rivers

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比较三种稳定剂对FeS纳米颗粒的稳定效果及对水土中镉的固定与去除性能的影响

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Journal of Central South University 2024年第4期31卷 1064-1075页

作者：田舒婷赵东叶霍丽娟马骏杨睿 Department of Environmental Science School of Environment and ResourcesTaiyuan University of Science and TechnologyTaiyuan 030024China Environmental Engineering Program Department of Civil&Environmental EngineeringAuburn UniversityAuburnAL 36849USA Department of Civil Constructionand Environmental EngineeringSan Diego State UniversitySan DiegoCA 92182USA

本研究评估了三种多糖稳定剂(羧甲基纤维素钠(CMC)、羧甲基淀粉钠(CMS)和一种水溶性淀粉)用于稳定FeS纳米颗粒的有效性,并测试了相应稳定化纳米颗粒在水和土壤中固定Cd^(2+)的性能。使用0.010 wt%CMC、0.025 wt%CMS或0.065 wt%淀粉可获... 详细信息

本研究评估了三种多糖稳定剂(羧甲基纤维素钠(CMC)、羧甲基淀粉钠(CMS)和一种水溶性淀粉)用于稳定FeS纳米颗粒的有效性,并测试了相应稳定化纳米颗粒在水和土壤中固定Cd^(2+)的性能。使用0.010 wt%CMC、0.025 wt%CMS或0.065 wt%淀粉可获得完全稳定的FeS纳米颗粒(100 mg/L FeS)。CMC-FeS表现出较高的zeta负电位,淀粉-FeS保持中性,而CMS-FeS则表现出中等负电位。CMCFeS对Cd^(2+)的吸附速率最快,吸附容量也最高。当用100 mg/L CMC-FeS或CMS-FeS处理一种含Cd土壤(58.3 mg/kg Cd)后,Cd的TCLP浸出率分别降低了88.4%和68.0%。CMC-FeS和CMS-FeS均可在模型土壤中运移,显示出其在土壤中原位固定Cd^(2+)方面的潜力。土壤穿透曲线实验表明,CMC-FeS在4.5个孔体积,CMS-FeS在约25个孔体积处几乎完全穿透。柱实验结果表明,当用55个孔体积的CMC-FeS或CMS-FeS悬浮液(100 mg/L)处理该含Cd土壤后,Cd的水浸出率分别降低了98.2%和98.0%。根据目标污染物、材料在土壤中的传输特性和材料成本,可找到这三种稳定剂在土壤修复中的最佳应用。

关键词：硫化铁纳米颗粒稳定剂重金属污染物固定土壤修复地下水污染

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Characteristics of self-compacting green concrete

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Discover civil engineering 2024年第1期1卷 1-14页

作者： Lim, Hung Ling Mannan, Mohammad Abdul Fakhri, Rana Shamseldeen Dawood, Eethar Thanon Teo, Delsye Ching Lee Tasnim, Sadia Department of Civil Engineering Faculty of Engineering Universiti Malaysia Sarawak (UNIMAS) Kota Samarahan Malaysia Department of Building and Construction Engineering Technical College of Mosul Northern Technical University Mosul Iraq Bachelor of Engineering Technology (Civil) Program Department of Business and Construction (Higher Education) Melbourne Polytechnic Epping Australia Applied Engineering South Metropolitan TAFE Munster Australia

Locally, conventional concrete is still created utilizing river sand and crushed stone as filer materials. The massive quarry dust by-product remain untapped in the production of concrete. The coal-fired power station produce significant quantities of Type F fly ash. Self-compacting concrete (SCC) provides many advantages for creating high-quality concrete. Consequently, the main objective of this research is to create a mix design for high-strength SCC utilizing a binary blends, hybrid fibers and fine aggregates that meet both hardened and fresh concrete characteristics. The study is conducted in amendment of w/b ratio, superplasticizer, proportion of fine aggregate to coarse aggregate, optimumal cement replacing by fly ash, dosage of low macro fibre and micro fibre. Mix-50c-X is the best mix design that was produced. The mix quantity for 1m3 concrete was 315 kg Class F fly ash, 315 kg OPC, 630 kg quarry dust, 508 kg river sand, 400 kg coarse aggregate, 0.7% superplasticizer,0.32% w/b, 0.10% macro fiber, and 0.01% micro fiber. This SCC mixture showed fresh characteristics as well as compressive strengths of more than 22 MPa and 62 MPa after 1 day and 28 days, respectively. The results of high-strength SCC demonstrated the enormous potential for the local construction, especially precast product.

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Massive plywood panels and manufacturers: a comprehensive systematic literature review and case study

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Discover civil engineering 2025年第1期2卷 1-24页

作者： De Araujo, Victor Alves, Larissa Jardim, Pedro Švajlenka, Jozef Christoforo, André Post-Graduation Program in Civil Engineering São Paulo State University Ilha Solteira Brazil Department of Civil Engineering Federal University of São Carlos São Carlos Brazil Department of Civil Engineering Federal University of Rondônia Porto Velho Brazil Department of Construction Technology Economy and Management Technical University of Košice Košice Slovakia

Massive timber is a category of heavy green engineered products, manufactured from glued or glued-free processes, to be used in more predictable structural performance in industrialized walls, floors and frames. Massive plywood panel emerges as a novelty for mass timber construction and, therefore, little information is scientifically available. Aligning with the Sustainable Development Goal 9: ‘Industry, innovation and infrastructures’, this study aims to verify this literature gap and raise topics regarding massive plywood panels using a structured systematic review literature. From bibliometric analysis, 12 journal papers, 10 conference papers and an editorial were prospected using Scopus and Web of Science databases. A predominance of studies from English language nations was confirmed. Seismic and monotonic performance of massive plywood are frequent topics in these investigations, whose results have indicated a promising scenario for construction. As no study on industry is available, a case study on massive plywood was sequentially developed to discuss features of commercial panels and perspectives of respective global industry. The North American Freres Engineered Wood and Finnish Metsä Wood are the only active manufacturers, and their massive plywood panels have been manufactured from modern production technologies and environmentally certified practices to be applied in low- and high-rise industrialized buildings.

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Use of Digital Elevation Model for Detecting Airfield Pavement Distress

Use of Digital Elevation Model for Detecting Airfield Paveme...

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2023 International Conference on Airfield and Highway Pavements

作者： All Sourav, Md. Abdullah Ceylan, Halil Kim, Sunghwan Brooks, Colin Peshkin, David Dobson, Richard Brynick, Matthew Dept. of Civil Construction and Environmental Engineering Iowa State Univ. AmesIA United States Dept. of Civil Construction and Environmental Engineering Program for Sustainable Pavement Engineering and Research Iowa State Univ. AmesIA United States Program for Sustainable Pavement Engineering and Research Institute for Transportation Iowa State Univ. AmesIA United States Michigan Tech Research Institute Ann ArborMI United States Applied Pavement Technology Inc. UrbanaIL United States Federal Aviation Administration Airport Pavement R&D Section NJ United States

ISBN: (数字)9780784484906

ISBN: (纸本)9780784484906

A digital elevation model (DEM) is a topographic representation of a bare surface, usually referring to the Earth's surface. DEMs have been used for flood assessment, landside hazard detection, soil properties' quantification, road and highway planning, etc. Recently, DEMs generated using small unmanned aircraft systems (sUAS) have shown potential in transportation infrastructure inspection. In this study, we evaluated the performance of sUAS-collected DEM data to detect airfield pavement distresses. Natural-color red-green-blue (RGB) data were collected from both Portland cement concrete (PCC) and asphalt concrete (AC) pavements at three airports with UAS. The data were processed to generate an RGB optical orthophoto using close-range photogrammetry, and one product of that process was a DEM representing the airfield pavement in three-dimensional space. The resolution of the generated DEMs varied from 2.8 mm/pix to 84 mm/pix based on sUAS sensors, flying altitude, and parameters selected for RGB data processing. The DEMs were studied for their usefulness in visually identifying 14 PCC pavement distresses and nine AC pavement distresses. Analysis showed that DEM with 6 mm/pix resolution or better can be useful for detecting one or more severity levels of 13 PCC pavement distresses and 6 AC pavement distresses. High-resolution DEMs were also useful in identifying distresses related to elevation differences, such as shoving, depression, and faulting. This study illustrates the potential of DEM data in airfield pavement distress detection. © ASCE 2023. All rights reserved.

关键词： Unmanned aerial vehicles (UAV)

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Experimental and Simulation Analysis of Rca and Para-Wood Ash as Partial Substitutes for Nca and Cement in Recycled Aggregate Concrete

SSRN

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SSRN 2024年

作者： Sae-Long, Worathep Chompoorat, Thanakorn Limkatanyu, Suchart Damrongwiriyanupap, Nattapong Sukontasukkul, Piti Chub-Uppakarn, Tanan Thepumong, Thanakit Civil Engineering Program School of Engineering University of Phayao Phayao56000 Thailand Department of Civil and Environmental Engineering Faculty of Engineering Prince of Songkla University Songkhla90110 Thailand Construction and Building Materials Research Center Department of Civil Engineering King Mongkut’s University of Technology North Bangkok Bangkok10800 Thailand

Recycled concrete aggregate (RCA) is widely used as an alternative recycled material in engineering, while para-wood ash (PWA) is a natural agricultural waste product. To advance sustainable construction, it is crucial to thoroughly examine their impact on concrete’s mechanical properties to ensure safety in engineering applications. This paper conducts a series of experiments on recycled aggregate concrete (RAC) with PWA to investigate these replacement effects. RCA replaces natural coarse aggregate (NCA) at 0%, 50%, and 100%, while PWA substitutes cement at 0%, 10%, and 20%. The experiments include compression tests on mortar as well as compressive, tensile, and flexural tests on RAC, along with microstructure investigations. The results indicate a decrease in strength with higher proportions of RCA and PWA. Microstructure investigations were conducted via scanning electron microscopy with energy-dispersive X-ray analysis (SEM/EDX). SEM provides micro images of the testing specimens, while EDX offers insight into their chemical compositions. The EDX results reveal a direct correlation between the Ca/Si ratio and the strengths of mortar and RAC. Correlation studies between compressive strength-replacement parameters, tensile-compressive strength, and flexural-compressive strength demonstrate that the proposed equations accurately predict the experimental data with R2 values of 0.60 (for mortar), and 0.94, 0.95, and 0.71 (for RAC), respectively. Two numerical simulations validate the proposed model and showcase potential engineering applications. Finally, a 10% replacement of PWA for cement can reduce the embodied energy value (EEV) by approximately 9.46% for mortar mixed with PWA and around 10% for RAC mixed with RCA and PWA. © 2024, The Authors. All rights reserved.

关键词： Mortar

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Evolution of large-strain one-dimensional consolidation test for louisiana marsh soil

Evolution of large-strain one-dimensional consolidation test...

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2021 International Foundations Congress and Equipment Expo: Geoenvironmental engineering, Geomaterial Modeling, Transporation Geotechnics, and Case Histories, IFCEE 2021

作者： Apu, Omar Shahrear Wang, Jay X. Sarker, Debojit Program of Civil Engineering Louisiana Tech Univ. RustonLA United States Programs of Civil Engineering and Construction Engineering Technology Louisiana Tech Univ. RustonLA United States

ISBN: (数字)9780784483435

In this paper, statistical analyses were conducted to understand the applicability and reliability of conventional consolidation tests on extremely soft dredged fill material. Of all the consolidated tests reviewed, specially designed and fabricated equipment was used to perform multiple one-dimensional consolidation tests on composite slurry samples prepared from the dredged borrow area. Data of over 30 consolidation tests were analyzed and assessed, and regression equations were proposed to estimate the compression index Cc. By comparing the proposed regression equations with the existing empirical equations, it was discovered that the compression index predicted by a simple linear equation considering the natural moisture content, initial void ratio, plastic limit, and liquid limit could sensibly assess the genuine soil compression index. In any case, the consolidation test on very soft dredged soils is time-consuming and work-intensive;it is likewise observed that the use of empirical equations recommended in this research results in a valuable tool to assess the compression index of the marine clayey soils used in the wetland recovery projects in coastal Louisiana. © ASCE.

关键词： Soils

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