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Influence of CDW Recycled Aggregate on Drying Shrinkage of Mortar

Open Journal of civil engineering 2012年第2期2卷 53-57页

作者： Paulo Roberto Lopes Lima Monica Batista Leite Civil and Environmental Engineering Post-Graduate Program State University of Feira de Santana Feira de Santana Bahia Brazil

The use of fine recycled aggregates as raw material in the production of mortars appears as a good alternative to minimize waste disposal, so as to reduce natural resources consumption and to find and supply suitable substitutes for natural aggregates. However, the use of this alternative material in a safe way must be carried out by a wide investigation of its long term behavior. In this way, this paper will examine the mechanical strength, physical properties and drying shrinkage of mortar, which use recycled fine aggregates that have originated from construction and demolition waste (CDW) containing mortar (55%), ceramic (26%) and concrete (16%). Two natural mortars, made with natural sand, were produced with cement/sand ratios of 1:4 and 1:8 (by weight) and a fixed consistency index of 260 +10 mm. Recycled mortar was produced with 50% of substitution rate, in volume, of natural aggregate by recycled one. Results show that recycled mortars present higher total porosity, absorption rate and drying shrinkage than reference mortar.

关键词： Recycled Mortar Construction and Demolition Waste Drying Shrinkage Recycled Aggregate

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An assessment of rolled stainless steel angles under compression 7th

An assessment of rolled stainless steel angles under compres...

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7th International Conference on Structural engineering, Mechanics and Computation, 2019

作者： da Sirqueira, A.S. da Vellasco, P.C.G.S. de Lima, L.R.O. da Silva, A.T. Rodrigues, M.C. Vellasco, M.M.B.R. PGECIV-Civil Engineering Post-Graduate Program UERJ – State University of Rio de Janeiro Brazil Structural Engineering Department UERJ – State University of Rio de Janeiro Brazil Electrical Engineering Department PUC-Rio – Pontifical Catholic University of Rio de Janeiro Brazil

ISBN: (纸本)9781138386969

Stainless steel has been used in several types of constructions. Although many of their mechanical properties are similar to the properties of carbon steel, their nonlinear characteristics imply in different design rules. This non-linearity mainly affects the response to local and flexural buckling. The Eurocode 3: Part 1-4 (2006) stainless steel design standard can be applied to hot rolled, welded and cold formed products, but the provisions of this code are rather conservative, with a limited application due to the lack of experimental data. Thus, one of those areas that require attention and study concerns the behaviour of columns made of rolled stainless steel angles. This paper describes an experimental campaign made on rolled stainless steel angles under axial compression. The tests were performed on stainless steel rolled angles with lengths varying from 150 mm to 1400 mm while the collapse involved: flexural-torsional and flexural buckling modes. © 2019 Taylor & Francis Group, London, UK.

关键词： Hot rolling

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Facades inspection with infrared thermography: cracks evaluation

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Journal of Building Pathology and Rehabilitation 2016年第1期1卷 1-7页

作者： Elton Bauer Elier Pavón Elias Oliveira Claudio H. F. Pereira Post-Graduate Program in Structures and Civil Construction Civil and Environmental Engineering Department University of Brasília Brasília Brazil Centro das Ciências Exatas e das Tecnologias Post-Graduate Program in Structures and Civil Construction - UnB Universidade Federal do Oeste da Bahia-UnB Barreiras Brazil

Infrared thermography is an evaluation technique that helps to identify anomalies and can provide information on their incidence and severity. The aim of this study is to apply quantitative thermography to study a case of severe cracks in facade analyzing the evolution of temperatures and Delta-T. The temperature evolution was studied over a day. There was sun incidence occurring during part of the day, allowing to calculate and assess the evolution of the associated temperatures. Thermograms were acquired hourly during the study period. The highest temperatures were observed at 12:00 noon, and the larger Delta-T between 10:00 and 12:00. There were differences between the Delta-T profiles among the three regions studied. The best time for analysis is when Delta-T is higher. Cracks with higher Delta-T were considered more degraded, and generalized branched cracks did not allow a comparative conclusion.

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Analysis of the possible failure modes in CSH bolted sleeve connections 15

Analysis of the possible failure modes in CSH bolted sleeve ...

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Proceedings of the 15th International Symposium on Tubular Structures, ISTS 2015

作者： Amparo, L.R. Sarmanho, A.M. De Araújo, A. Requena, J. Post-Graduate Program in Civil Engineering Federal University of Ouro Preto Ouro PretoMG Brazil V&M do Brasil S. A Belo HorizonteMG Brazil State University of Campinas CampinasSP Brazil

ISBN: (纸本)9781138028371

Steel circular hollowsections (CHS) have good resistance under tension, compression and torsion loads, considered isolated or combined. Recent researches have been carried out to evaluate the behavior and resistance of these structures. A current use of steel hollow sections is roof trusses, a kind of structure that demands standard procedures and fast assemblage. This work presents an experimental study of a new type of connection called sleeve, developed to attend the assembly process. The connection consists of two tubes internally connected through a third tube with a smaller diameter with passing bolts arranged in line and cross. This connection makes easier the structure assemblage and is aesthetically advantageous if compared to usual flanged connection used in hollow sections. An experimental program of the sleeve connection with bolts in line (along the tube) and crossed at 90◦ was developed. In this work were tested 3 prototypes with staggered bolts to complement previous research and 12 prototypes with crossed bolts. The parameters considered in investigation were tube diameter and thickness and number of bolts. Experimental results lead to identification of failure mode and the resistance of sleeve connection. The analysis of theoretical and experimental data revealed that the dominant failure mode was bending in the bolts, and indicated a reduction in connection resistance that needs to be quantified. For the prototypes with staggered bolts, the analysis also let the development of an expression for the determination of flexural failure in the bolts. The results have demonstrated the viability of this new type of connection, but indicated that all possible failure modes need to be carefully checked. © 2015 Taylor & Francis Group, London.

关键词： Failure modes

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Review of the use of mangrove forests in supporting the socio-economic life of fishing communities 2

Review of the use of mangrove forests in supporting the soci...

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2nd International Conference of Interdisciplinary Research on Green Environmental Approach for Sustainable Development, ICROEST 2020

作者： Untari Darma, R. Betaubun, P. Arief, A.A. Graduate School Hasanuddin University South Sulawesi Indonesia Department of Agribusiness Faculty of Agriculture Universitas Musamus Papua Indonesia Agribusiness Study Program Faculty of Agriculture Hasanuddin University South Sulawesi Indonesia Department of Civil Engineering Faculty of Engineering Universitas Musamus Papua Indonesia Socio Economic of Fisheries Study Program Faculty of Marine Science and Fisheries Hasanuddin University South Sulawesi Indonesia

Mangrove forests have an important function in human life that cannot be replaced by other functions. The existence of mangrove forests has six main functions, namely biological, ecological, physical, social, economic and chemical functions. This article discusses the description of mangrove forest management in meeting the needs of the economic and social functions of the fishing communities on the coast of Merauke Regency, Papua Province, which were reviewed descriptively using relevant literature studies. In terms of economic function, mangrove forests provide economic value for fishing communities because mangrove forests become habitat for crabs, fish and other marine biota that are captured and sold as the main source of family income. In addition, the use of mangrove forests by fishermen on the coast is used as firewood and building materials. The high utilization of mangrove forests by coastal communities that ignores ecological sustainability causes damage to mangrove forests that threatens the sustainability of ecological functions. Damage to mangrove forests in Merauke in the period 2000-2005 was recorded as wide as 2,416 ha while in the 2005-2010 period damage reached 2,233 ha of the total area of the Merauke mangrove forest which reached 216,001.95 Ha or 6.98% of the Merauke forest area. Based on this, the management of mangrove forest utilization needs to get more attention from various parties so that the ecological function of mangrove forests as a condition of sustainable development, especially for fishing communities on the coast, can be realized in Merauke Regency. © Published under licence by IOP Publishing Ltd.

关键词： Sustainable development

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study of damage distribution and intensity in regions of the facade

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Journal of Building Pathology and Rehabilitation 2016年第1期1卷 1-9页

作者： de Souza, Jessica S. Bauer, Elton Nascimento, Matheus L. M. Capuzzo, Valdirene M. S. Zanoni, Vanda A. G. Post-Graduate Program in Structures and Civil Construction Civil and Environmental Engineering Department University of Brasília Campus Universitário Darcy Ribeiro Asa Norte Brasília 70910-900 DF Brazil Faculty of Architecture and Urbanism University of Brasília Campus Universitário Darcy Ribeiro Asa Norte Brasília 70910-900 DF Brazil

The ceramic coating systems applied to building facades have relevant aesthetic value and protection functions. The architectural and environmental conditions can greatly influence the degradation process of the facades, which may pose risks and compromise the durability and service life of the building and its components. The degradation process of facades changes according to the region where it takes place. To this end, the present study aims to determine damage intensity and distribution in the different regions of the facade. This study investigated the facades of three buildings that are part of the Materials Testing Laboratory (LEM) database of the Universidade de Brasilia. The degradation was quantified using a methodology proposed by Silva (2014) to generate a degradation index expressed in m². After the quantification of damages, few indexes associated with the percentage of degraded area, applied to the facade regions, are presented. These weighted indexes allowed to standardize the values observed in each region. Obtaining these indices is fundamental to the study of degradation. The results show that for a comparative analysis between the regions, the observed values should be corrected for the proportionality of the area of each region in relation to the total area of the facade. It was also noted that the continuous walls are the most affected regions, but they do not always present the highest damage intensity. © 2016, Springer International Publishing Switzerland.

关键词： Damage distribution Degradation Degradation index Facades Pathology

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Wind-driven rain incidence parameters obtained by hygrothermal simulation

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Journal of Building Pathology and Rehabilitation 2016年第1期1卷 1-7页

作者： Nascimento, M.L.M. Bauer, E. de Souza, J.S. Zanoni, V.A.G. Post-Graduate Program in Structures and Civil Construction Civil and Environmental Engineering Department University of Brasília Campus Universitário Darcy Ribeiro Asa Norte Brasília 70910-900 DF Brazil Faculty of Architecture and Urbanism University of Brasília Campus Universitário Darcy Ribeiro Asa Norte Brasília 70910-900 DF Brazil

The association of rain and wind composes wind-driven rain (WDR), and its incidence may be crucial to the emergence of anomalies on the facades of buildings. Moisture from the WDR can influence the humidification and drying process, therefore the durability and hygrothermal performance are conditioned by the amount of incident water. The quantification of WDR can be an indispensable tool for understanding its related phenomena and the service life of buildings. The most widely used methods of quantification are the semi-empirical, with theoretical basis, but coefficients partially determined from measurements. These methods may take into account the building exposure conditions related to the envelope, solar orientation, height of the building, and other parameters. In this context, in order to contribute to the studies on quantification of WDR, the purpose of this paper is to apply hygrothermal simulation software WUFI^® on quantification of WDR focusing on buildings degradation of Brasília-Brazil. For the simulation it was used a Typical Meteorological Year file with the wind and precipitation measurement data indispensable for simulation. The quantification of incidence of WDR considered the orientations North, Northeast, East, Southeast, South, Southwest, West, and Northwest. The use of semi-empirical WUFI^® quantification method allowed finding the highest values and consequently critical orientations North, Northwest, and Northeast, moreover, this results showed the relation with the degradation of facades in these orientations. WUFI proved to be an easy, fast and efficient method of WDR quantification, without hiding seasonal weather effects. © 2016, Springer International Publishing Switzerland.

关键词： Degradation Facade Hygrothermal simulation Wind-driven rain

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study of soil structure interaction on basement wall with variants in distance and depth of the basement on soil class SE 2

Study of soil structure interaction on basement wall with va...

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2nd Joint International Conference on Emerging Computing Technology and Sports, JICETS 2019

作者： Saragi, Yetty Irsyam, Masyhur Roesyanto Hendriyawan University of Hkbp Nommensen Sutomo Street No.4A Medan20234 Indonesia Post Graduate Program Civil Engineering Departement University of Sumatera Utara Medan-North Sumatera20155 Indonesia Institute of Technology Bandung Ganesha 10 Bandung West-Java40135 Indonesia Civil Engineering Departement University of Sumatera Utara Medan North-Sumatera20155 Indonesia

The function of the basement is to carry the weight of the upper structure into the soil and to resist lateral loads around the basement wall. One aspect of geotechnical engineering that often a problem in basement wall planning is the determination of lateral ground pressure in the basement wall due to earthquake which must be held by the basement wall. In this study, an analysis of the effects of local soil conditions due to dynamic loads is done through analysis of soil-structure interaction. The analysis is done by modeling the local soil with variations in basement depth and the adjacent basement distance to get the lateral pressure distribution due to dynamic load. The analyzed soil conditions are considered homogeneous at land sites SE (soft soil) with the dynamic load input from earthquake loads uses a 10% probability of exceedance in 50 years (500 years). The most influential parameter for soil displacement is the distance of the basement and then the depth of the basement. The most influential parameter on lateral forces is the depth of the basement followed by the distance of the basement. © 2020 IOP Publishing Ltd. All rights reserved.

关键词： Dynamic loads

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Comparison of Taylor Galerkin and FTCS models for dam-break simulation 5

Comparison of Taylor Galerkin and FTCS models for dam-break ...

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5th International Seminar on Sustainable Urban Development, ISoSUD 2020

作者： Hafiyyan, Q. Adityawan, M.B. Harlan, D. Natakusumah, D.K. Magdalena, I. Graduate School of Civil Engineering Bandung Institute of Technology Jawa Barat Bandung Indonesia Center for Coastal and Marine Development Bandung Institute of Technology Jawa Barat Bandung Indonesia Study Program of Water Resouces Engineering and Management Bandung Institute of Technology Jawa Barat Bandung Indonesia Study Program of Water Resources Engineering Bandung Institute of Technology Jawa Barat Bandung Indonesia Industrial and Financial Mathematics Research Group Bandung Institute of Technology Jawa Barat Bandung Indonesia

The aim of this paper is to compare the ability of two numerical models to simulate two-dimensional dam-break flows. Dam-break modelling is important in reducing the high-risk of dam failure by determining the water flow movement and its effect on buildings downstream. In this study, the Taylor Galerkin and Forward Time Central Space method is presented to simulate 2-D dam-break flow. The Hansen filter is applied to both methods to reduce numerical instability oscillations in the model. The filters were used for each time step at each computing point. The model is verified by comparing the result simulation with numerical results from previous studies. The result show that Taylor Galerkin numerical scheme with Hansen filter is successful to simulate the problem of 2-D dam-break. Also, the Taylor Galerkin model has better results than the FTCS model. Studies like this are needed for mitigation efforts in the event of dam failure. © Published under licence by IOP Publishing Ltd.

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Polymer concrete reinforced with luffa fibers: Effect of gamma radiation

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Revista Tecnica de la Facultad de Ingenieria Universidad del Zulia 2014年第3期37卷 22-29页

作者： Martínez-Barrera, Gonzalo Martínez-López, Miguel Vigueras-Santiago, Enrique Gencel, Osman Beycioglu, Ahmet Dos Reis, João Marciano Laredo Facultad de Química Universidad Autónoma del Estado de México Km.12 de la carretera Toluca-Atlacomulco San Cayetano Mexico Civil Engineering Department Faculty of Engineering Bartin University Bartin Turkey Civil Engineering Department Faculty of Technology Düzce University Düzce Turkey Theoretical and Applied Mechanics Laboratory - LMTA Mechanical Engineering Post Graduate Program - PGMEC Universidade Federal Fluminense - UFF RuaPasso da Pátria 156 Bl. E sala 216 Niterói RJ Brazil

The interest of many research groups regarding manufacture of composite materials by using natural fibers is increasing world-wide. The main objectives involve the improvement of mechanical properties, mainly those related to resistance and elasticity. In the present study in a first stage, polymer concrete specimens were elaborated by using an unsaturated polyester resin, silica sand and luffa fibers; after, they were gamma irradiated at different doses and their mechanical properties were evaluated. Two different silica particle sizes (0.15 mm and 0.6 mm), and four different luffa fiber concentrations (0.3, 0.6, 0.9 and 1.2 wt%) were used, as well as 50 and 100 kGy of radiation dose. The results show a gradually diminution of compressive strength and modulus of elasticity when adding luffa fiber concentration. Nevertheless, such mechanical features are increasing when polymer concrete is gamma irradiated.

关键词： Unsaturated polymers

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