Civil Engineering Design最新文献_第9页

Effect of admixtures and supplementary cementitious material on mechanical properties and durability of concrete 外加剂和补充胶凝材料对混凝土力学性能和耐久性的影响

Civil Engineering Design Pub Date : 2020-03-06 DOI: 10.1002/cend.201900016

Gholamreza Asadollahfardi, Behnaz Yahyaei, Amir M. Salehi, Arash Ovesi

{"title":"Effect of admixtures and supplementary cementitious material on mechanical properties and durability of concrete","authors":"Gholamreza Asadollahfardi, Behnaz Yahyaei, Amir M. Salehi, Arash Ovesi","doi":"10.1002/cend.201900016","DOIUrl":"10.1002/cend.201900016","url":null,"abstract":"We studied the effects of superplasticizer (SP) (PCE1 and PCE2), air-entraining admixtures (AEA), and supplementary cementitious material (silica fume and fly ash) on the mechanical and durability properties of concrete samples. Eight concrete mix designs were prepared. The first six concrete mix design contained similar aggregates, PCE2 SP, AEA, 350 kg/m3 cement, and water to cement ratio equal to 0.38, and one of the mentioned mix design was selected as control samples with water to cement ratio equal to 0.57, without PCE2 SP and AEA. We used a different quantity of PCE2 SP and AEA and replaced the fly ash or silica fume as part of cement in two of the mentioned mix designs. The last two concrete mix designs studied the effect of PCE1 SP and AEA on freezing and thawing of concrete mix design. Adding PCE2 SP in concrete mix design increased compressive strength at age 11, 42, and 90 days sharply and reduced the depth of water penetration at the age of 28 and 90 days compared to the control sample. Using simultaneous PCE2 and AEA in concrete mix design did not improve compressive strength significantly and increased slightly depth of water penetration compared to only using PCE2. However, increasing the quantity of AEA to 5% improved both compressive strength and reduced depth of water penetration. In the second group of concrete mix design, adding both PCE1 and AEA increased the number of resistible freezing and thawing cycles of concrete. Side chain length and molecular weight of PCE1 and PCE2 SPs had no important effect on the compressive strength and performance properties of concrete.","PeriodicalId":100248,"journal":{"name":"Civil Engineering Design","volume":"2 1-2","pages":"3-11"},"PeriodicalIF":0.0,"publicationDate":"2020-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/cend.201900016","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"92682475","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}

引用次数: 5

An experimental investigation of bond strength of AFRP bars with self-consolidating concrete AFRP钢筋与自固结混凝土粘结强度的试验研究

Civil Engineering Design Pub Date : 2019-11-27 DOI: 10.1002/cend.201900013

Emmanuel Chinaka, Mehdi Shokouhian, Monique Head, Steve Efe

引用次数: 4

Mechanical characterization and out-of-plane behavior of fabric-reinforced cementitious matrix overlay on clay brick masonry 粘土砖砌体纤维增强胶凝基质覆盖层力学特性及面外行为

Civil Engineering Design Pub Date : 2019-11-13 DOI: 10.1002/cend.201900021

Ömer S. Türkmen, Boy T. de Vries, Simon N. M. Wijte

{"title":"Mechanical characterization and out-of-plane behavior of fabric-reinforced cementitious matrix overlay on clay brick masonry","authors":"Ömer S. Türkmen, Boy T. de Vries, Simon N. M. Wijte","doi":"10.1002/cend.201900021","DOIUrl":"10.1002/cend.201900021","url":null,"abstract":"The mechanical behavior of carbon fiber-reinforced polymer (CFRP) fabric-reinforced cementitious matrix (FRCM) overlay on clay brick masonry was characterized by means of double-shear bond, tensile, and out-of-plane tests. Different bond lengths in the range 55-250 mm were analyzed during the double-shear bond tests. The failure mechanism was slippage of the CFRM mesh, with peak stresses in the fabric around 500 N/mm2 per 100 mm bond length. Tensile tests were performed following AC434.13 with FRCM coupons of 10 and 15 mm thickness, where the mechanical behavior was divided into three stages. The four-point bending experiments on FRCM-reinforced prisms showed that the CFRP mesh provided significant added value in both moment capacity (>110%) and deformation capacity (>2800%), when compared to specimens reinforced with solely a cementitious matrix. Additionally, no significant difference was observed between the envelope of the cyclically tested specimen and the statically loaded specimens. A model was proposed where, in contrast to existing design models, the influence of the cementitious matrix layer also was considered. Using the modified tensile test results as input parameters for the model, a good estimation of the experimental results was obtained.","PeriodicalId":100248,"journal":{"name":"Civil Engineering Design","volume":"1 5-6","pages":"131-147"},"PeriodicalIF":0.0,"publicationDate":"2019-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/cend.201900021","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"96635873","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}

引用次数: 3

Stress-strain analysis in the window zone area of full-scale wall models made of AAC and calcium silicate units AAC与硅酸钙全尺寸墙体模型窗区应力-应变分析

Civil Engineering Design Pub Date : 2019-11-13 DOI: 10.1002/cend.201900022

Łukasz Drobiec

引用次数: 2

Post-installed mechanical fasteners in high strength and ultra-high strength performance concrete 高、超高强度混凝土后安装机械紧固件

Civil Engineering Design Pub Date : 2019-10-21 DOI: 10.1002/cend.201900015

Michael Schwenn, Klaus Voit, Oliver Zeman, Konrad Bergmeister

{"title":"Post-installed mechanical fasteners in high strength and ultra-high strength performance concrete","authors":"Michael Schwenn, Klaus Voit, Oliver Zeman, Konrad Bergmeister","doi":"10.1002/cend.201900015","DOIUrl":"10.1002/cend.201900015","url":null,"abstract":"Post-installed fastening systems are essential in structural engineering nowadays. Triggered by the increasing popularity of high strength concrete (HSC) and ultra-high performance concrete (UHPC), fastening in these basements is more and more frequently applied. This inevitably leads to the question of the applicability of conventional fastening systems and the corresponding design concepts with concrete showing a compressive strength of up to 200 N/mm2. According to EAD 330232-00-0601, mechanical fasteners have to be placed in predrilled holes in compacted reinforced or unreinforced concrete without fibers with strength classes in the range of C20/25 to C50/60 in compliance with EN 206. This means that concrete strength class C50/60 also provides the reference for higher concrete strength; the impact of fibers and accompanying increase of concrete ductility is also excluded. Within the framework of this contribution it is intended to analyze the following aspects: (a) proof of applicability of various fastening systems in unreinforced and fiber-reinforced high strength concrete via experimental investigations and (b) making a statement regarding the currently valid European Assessment Document and provide experimental background for this issue.","PeriodicalId":100248,"journal":{"name":"Civil Engineering Design","volume":"1 5-6","pages":"161-167"},"PeriodicalIF":0.0,"publicationDate":"2019-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/cend.201900015","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80624590","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 10

Calculation of risk costs in construction projects 建设项目风险成本的计算

Civil Engineering Design Pub Date : 2019-08-10 DOI: 10.1002/cend.201900014

Stefanie Brokbals, Vincent Wapelhorst, Ivan Čadež

{"title":"Calculation of risk costs in construction projects","authors":"Stefanie Brokbals, Vincent Wapelhorst, Ivan Čadež","doi":"10.1002/cend.201900014","DOIUrl":"10.1002/cend.201900014","url":null,"abstract":"As early as 1971, Schubert made a first contribution to the consideration of risks during the execution of construction projects. In addition to that, he was first to introduce elements of the risk management process to the construction management literature in Germany. By the use of an empirical study of the probability of risk occurrence and the cost amount by risk occurrence, Schubert made among others a statement about the importance of the risks depending on the amount of the risk costs. In an updated study for building construction projects with construction costs ≤2.5 million € and unit price contracts applying the VOB/B primarily the altered risk evaluations are shown; it needs to be emphasized that the sum of the determined risk costs corresponds to Schubert's results. Furthermore, with a variation of the characteristic attributes (response options) of the probability of risk occurrence and the cost amount by risk occurrence, it can be displayed that the risk costs during the execution of building construction projects are even considerably higher. Additionally, a probabilistic risk cost calculation — applying the Monte Carlo method — is used to reveal the bandwidth of risk costs. It can be pointed out that the risk costs range between 2.71% and 8.67% of the construction costs. The results could serve as a benchmark for contractors during the tender calculation to determine the amount of risk costs depending for example, on the market situation, the company-specific risk disposition as well as strategic considerations.","PeriodicalId":100248,"journal":{"name":"Civil Engineering Design","volume":"1 3-4","pages":"120-128"},"PeriodicalIF":0.0,"publicationDate":"2019-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/cend.201900014","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85555944","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Static and dynamic behavior of cellular glass products used for the bottom insulation of flat bottom tanks 用于平底罐底部绝缘的多孔玻璃制品的静态和动态性能

Civil Engineering Design Pub Date : 2019-08-05 DOI: 10.1002/cend.201800003

Till Waas, Robert Hertle, Marian Krol

引用次数: 0

Distributed fiber optic sensing for crack detection in concrete structures 分布式光纤传感在混凝土结构裂缝检测中的应用

Civil Engineering Design Pub Date : 2019-07-29 DOI: 10.1002/cend.201900008

Oliver Fischer, Sebastian Thoma, Simone Crepaz

引用次数: 35

Multiaxial and variable amplitude fatigue of concrete 混凝土的多轴变幅疲劳

Civil Engineering Design Pub Date : 2019-07-13 DOI: 10.1002/cend.201900010

Peter Heek, Peter Mark