工民建工程施工中混凝土裂缝的控制研究

为更好的控制工民建施工中混凝土裂缝,本文基于混凝土裂缝的常见种类,分析了这些裂缝的形成原因,从工程设计方面、工程施工方面以及混凝土比例等方面提出了一系列预防工民建施工中混凝土裂缝的方法,并总结一些常用的混凝土裂缝修补方法,以供同行参考。     

谈混凝土裂缝预防与控制

介绍了混凝土裂缝的分类,针对混凝土裂缝产生的原因,从勘察设计阶段、施工阶段、环境温度影响等方面,阐述了混凝土裂缝的预防与控制措施,从而确保混凝土构件的施工质量。     

大体积混凝土裂缝分析和防治

分析了混凝土施工裂缝产生的原因,从施工中的混凝土材料要求、混凝土浇捣与养护等方面进行了裂缝防治及处理措施的阐述,达到满足工程使用性和耐久性要求,从施工上避免了混凝土裂缝的产生。     

地下室混凝土裂缝的成因分析及预防

从混凝土浇筑及养护两方面分析了混凝土裂缝产生的原因,从施工操作、施工方案、材料、施工质量等方面研究了混凝土裂缝的预防措施,以减少工程裂缝,从而达到提高工程质量的目的。     

泵送混凝土现浇楼板裂缝预防措施

针对泵送混凝土容易出现裂缝的问题,从塑性收缩裂缝、沉降裂缝、施工荷载引起的裂缝等方面阐述了泵送混凝土现浇楼板裂缝的预防措施,以积累泵送混凝土施工经验,从而提高建筑工程的质量。     

混凝土大坝裂缝成因分析与防治措施综述

具体分析了混凝土大坝产生裂缝的原因,从结构方面、材料方面、施工方面及综合管理方面提出了防止混凝土裂缝的措施,并对混凝土大坝表面裂缝危害进行了分析,提出对混凝土表面进行保护,可以有效地减少表面裂缝的产生.     

承台大体积混凝土冷却系统设计施工方案

大体积承台混凝土施工裂缝控制是承台施工的重点,围绕承台混凝土施工裂缝控制,从水化热控制、冷却系统设置、温控监测等方面系统阐述了对混凝土施工温度的控制,避免混凝土表面和内部裂缝的产生,为相关工程施工提供借鉴。     

混凝土路面裂缝控制处理技术探讨

结合工程实践,介绍了混凝土路面产生裂缝的种类和原因,分析了影响混凝土路面裂缝开裂的因素,从材料质量、施工前准备工作、施工过程等方面阐述了混凝土路面裂缝的防止与控制,以期提高混凝土路面施工质量。     

现浇混凝土裂缝产生的原因及防治

裂缝是混凝土在施工中常见的一种质量通病,为了降低混凝土裂缝的发生,文章针对建筑施工中混凝土裂缝的产生展开分析,论述了各种类型裂缝的形成原因,从表面裂缝、设计、材料、混凝土配合比、施工与养护等几个方面讨论防治对策,制定完善的混凝土裂缝防治方案,有效地降低混凝土裂缝产生。     

预拌泵送混凝土施工裂缝的分析和预防及处理

分析了预拌泵送混凝土施工裂缝所产生的原因,从施工中的预拌混凝土材料要求、混凝土浇捣与养护等方面进行了裂缝防治及处理措施的阐述,达到满足工程使用性和耐久性要求,从施工上避免了混凝土构件裂缝的产生。     

浅析高速公路工程招投标中的最低评标价法

结合目前高速公路施工项目招投标活动的实际情况,阐述了最低评标价法的概念,归纳了其优点及存在问题,对完善最低评标价法提出几点策略,以期促进招标投标市场更加规范有序。     

Place-Making in Megaprojects in Melbourne

This article analyses state-led place-making practices in Melbourne. The two levels of government that influence planning in Melbourne make much of the city as ‘culturally vibrant’ and ‘creative’, and have incorporated creative city-inspired place-making principles into many layers of the planning system. An examination of the development of two mixed-use megaprojects in central Melbourne reveals however that ideals of culturally engaging public places, and indeed of creative landscapes for middle-class consumption, wither in the face of more basic imperatives for economic development. In these case studies the ‘creative city’, no matter how the idea is interpreted, has little traction either as a set of inclusive place-making principles or as a gentrification strategy. The article concludes that the creative city-inspired place-making objectives in the planning system at both state and local levels are ambiguous in their overall intents and completely unsupported by statutory controls. Such place-making objectives as are realised are the compromised results of the interplay of uncoordinated decisions, delivered at the pleasure of the developer.     

Pathogens in septage in Vietnam

Septage is widely acknowledged as a major source of infectious pathogens while disposal of septage, and the operation and maintenance of septic tanks, is not regulated in many developing countries. Twenty untreated septage and septage sludge samples were taken from Can Tho City, Vietnam to examine their pathogen content, and indicator micro-organisms. Escherichia coli and Enterococcus spp. were detected in all samples, regardless of sludge storage time. Phages were detected in 80% of samples. Salmonella spp. were detected in 70% of the untreated septage and 60% of septage sludge samples. Concentrations of phages and bacteria tested in septage sludge after many years of tank storage were much higher than the expected levels. Helminth ova were present in 95% of untreated septage samples with an average of 450 ova l^− 1, and were detected in all septage sludge samples with an average of 16,000 ova l^− 1. Twelve varieties of helminth ova were identified. More helminth ova varieties in higher concentrations were found in septage than those reported from stool samples. The varieties' frequency ranged from 10% to 50% and Ascaris lumbricoides predominated. Results show that pathogens and indicator micro-organisms, especially helminth ova, accumulate in sludge. Thus helminth ova should be considered when septage sludge is treated and used for agriculture. Proper health protection measures must be applied for people handling septage.     

新时期广东城市化的新特点

新时期广东城市化出现以下特点:知识源导向、城市由单体向群体化发展、产业集群推动、政府主导自上而下的集约化发展、城镇化向城市化转变、由重“数量”发展向重“质量”发展的转变。     

谈城市历史保护规划的误区

由于缺乏起码的历史文化知识,忽视历史文化遗产的保护,错误的决策导致了建设性的破坏,要加强城市保护的教育,培养合格人才。     

浅谈我国工程项目建设成本控制存在的问题

结合目前我国施工企业工程项目成本管理现状,对工程项目成本管理过程中存在的问题进行了较详细的分析,并提出了一些解决问题的办法,以做好项目成本控制工作,进而增强企业经济实力。     

浅谈建筑施工临时用电安全

针对由于建筑施工临时用电安全管理的不完善和不规范操作而导致大量工伤事故频频发生的问题,为消除用电安全隐患,对建筑施工临时用电安全管理进行了归纳和分析,并提出了整改意见,以确保现场人员及电气设备的安全运行。     

Perchlorate exposure in lactating women in an urban community in New Jersey

Perchlorate is most widely known as a solid oxidant for missile and rocket propulsion systems although it is also present as a trace contaminant in some fertilizers. It has been detected in drinking water, fruits, and vegetables throughout New Jersey and most of the United States. At sufficiently high doses, perchlorate interferes with the uptake of iodine into the thyroid and may interfere with the development of the skeletal system and the central nervous system of infants. Therefore, it is important to quantify perchlorate in breast milk to understand potential perchlorate exposure in infants. In this study we measured perchlorate in breast milk, urine, and drinking water collected from 106 lactating mothers from Central New Jersey. Each subject was asked to provide three sets of samples over a 3-month period. The average ± SD perchlorate level in drinking water, breast milk, and urine was 0.168 ± 0.132 ng/mL (n = 253), 6.80 ± 8.76 ng/mL (n = 276), and 3.19 ± 3.64 ng/mL (3.51 ± 6.79 μg/g creatinine) (n = 273), respectively. Urinary perchlorate levels were lower than reference range values for women of reproductive age (5.16 ± 11.33 μg/g creatinine, p = 0.03), likely because of perchlorate secretion in breast milk. Drinking water perchlorate levels were ≤ 1.05 ng/mL and were not positively correlated with either breast milk or urine perchlorate levels. These findings together suggest that drinking water was not the most important perchlorate exposure source for these women. Creatinine-adjusted urine perchlorate levels were strongly correlated with breast milk perchlorate levels (r = 0.626, p = < 0.0005). Breast milk perchlorate levels in this study are consistent with widespread perchlorate exposure in lactating women and thus infants. This suggests that breast milk may be a source of exposure to perchlorate in infants.     

安康市工程施工企业未来几年人才需求调查

为了不断提高工程类专业的办学质量,对安康市区主要施工企业或项目经理部未来几年人才需求状况进行了调查,同时提出相关建议,以期培养更多的该类专业人才,满足施工企业需求。