谈清水混凝土施工技术

本文从模板施工、混凝土浇筑、加强现场管理等方面详细阐述了工业厂房工程中清水混凝土施工技术及施工质量控制要点,保证混凝土施工建筑,表面平整、色泽一致.     

论混凝土在建筑施工技术的应用

当今的建筑技术不断发展,泵送混凝土施工技术得到普及和应用.泵遣混凝土不仅能改善混凝土的施工性能,对薄壁密筋结构少振捣或不振捣施工.具有提高抗渗性、改善耐久性特点.但是混凝土材料品质及配合比质量的波动以及混凝土输送、浇筑、养护等施工工艺对混凝土质量有较大的影响,施工过程中需要严格的质量控制.     

大面积厂房地坪的施工

通过某冶金厂房大面积混凝土地坪施工,介绍了大面积混凝土地坪的施工技术、工艺措施及施工缝与伸缩缝协调处理等经验,提出保证大面积混凝土地坪施工质量的方法.     

怎样做好沥青混凝土路面施工质量控制

高等级公路沥青混凝土路面施工应贯彻"精心施工、质量第一"的方针,保证沥青混凝土路面施工质量,使铺筑的沥青混凝土路面坚实、耐久、平整、稳定,为社会提供安全、舒适、舒畅的交通条件,这也是评价沥青混凝土路面性能的标准.本文着重论述怎样做好沥青混凝土路面施工质量控制.     

高层建筑现场混凝土施工质量综合控制管理措施

混凝土作为高层建筑用量最大的建筑工程材料,其施工质量直接关系到高层建筑的整体质量,因此,必须加强高层建筑现场混凝土施工的管理。本文首先概述了高层建筑混凝土施工质量的影响因素,进而从具体方面论述混凝土施工质量管理措施,可以为高层建筑混凝土施工管理提供合理的参考。     

浅探亚硫酸钠工程混凝土冬期施工技术

混凝土冬期施工在我国北方地区是不可避免的，正确选择技术可行、经济合理、可操作性强的混凝土冬期施工技术，是确保混凝土质量的关键。本文以亚硫酸钠工程的混凝土冬期施工技术为例，对混凝土冬期施工技术进行粗浅的探讨，诣在总结其成功的经验并加以推广。     

钢管混凝土柱施工技术

文章结合工程实践,对钢管混凝土结构施工中,钢管混凝土柱的制作、安装及钢管混凝土顶升浇注施工方法进行了总结。     

大体积混凝土施工技术分析

以武汉钢铁集团鄂城钢铁有限责任公司矿渣微粉工程磨机基础为例.分析了大体积混凝土技术.混凝土浇筑的施工方法等进行了分析。通过采用严密的施工组织措施、合理的配合比设计、先进的温度控制和监测手段、科学的浇灌和养护方法,实现了大体积混凝土施工,基础施工完成后未产生有害裂缝,混凝土浇筑质量良好。     

超大跨度预应力混凝土梁施工技术

文章以赤峰国际会展中心工程为背景,深入探讨本工程超大跨度预应力混凝土梁施工的关键技术,详细介绍了施工过程中的材料准备、混凝土梁模板及支撑体系的设计、预应力钢筋安装、混凝土浇筑及养护、孔道灌浆等主要环节,对大跨预应力混凝土梁的施工具有较高的参考价值。     

矿山混凝土结构施工技术的应用

对矿山混凝土结构的施工原则作了概述,对矿山混凝土结构施工的的影响因素进行了总结,从模板安装、混凝土浇筑、振捣、养护等角度对施工工艺和施工方法进行了分析,并提出了相应的注意事项,从根本上提高矿山混凝土结构的施工质量,有效延长结构的使用寿命。     

Effect of Envelope on Residential Cooling Load Coupled with Use of Solar/Photovoltaic Panels

Three identically oriented homes were used for the study. Two of the homes were identically constructed using wood frame/stucco construction while the third used a wall of sandwiched Styrofoam in between concrete layers. It was found that the concrete house on the average consumed about 15% less energy for HVAC operation than the wood frame houses. Also the photovoltaic array placed on the roofs of two of the houses indicated a reduction in electrical energy consumption from the grid of about 20% of the HVAC electrical energy consumed. TRACE-700 simulation runs were made on both types of houses to determine the design cooling load for each of the houses and the total consumed electrical energy for each house over the whole year on a monthly basis. It was found that in the summer a 20% reduction of electrical energy for HVAC is predicted due to the use of the concrete house as compared to the wood frame homes. In addition a linear correlation was found to represent reasonably well the variation of the daily kilowatt hour versus the daily degree day value for a typical summer month in the Las Vegas, Nev. valley for all three houses. The slope of that line for the concrete home was about 24% less steep than the line for the wood frame construction confirmation in part theoretical calculations that this wall construction is more energy conserving than the base case.     

Stringless Portland Cement Concrete Paving

This paper describes results from a study evaluating stringless paving using a combination of global positioning and laser technologies. A concrete paver manufacturer and a machine guidance solution provider developed this technology and successfully implemented it on construction earthmoving and grading projects. Concrete paving is a new area for considering this technology. A concrete paving contractor in Iowa agreed to test the stringless paving technology on two challenging concrete paving projects located in Washington County, Iowa during the summer of 2003. The research team from Iowa State University monitored the guidance and elevation conformance to the original design. They employed a combination of physical depth checks, surface location and elevation surveys, concrete yield checks, and physical survey of the control stakes and string line elevations. A final check on profile of the pavement surface was accomplished by the use of the Iowa Department of Transportation Light Weight Surface Analyzer. Due to the speed of paving and the rapid changes in terrain, the laser technology was abandoned for this project. Total control of the guidance and elevation controls on the slip form paver were moved from string line to a global positioning system (GPS). Results indicate that GPS control is a feasible approach to controlling a concrete paver. Further enhancements are needed in the physical features of the slip form paver hydraulic system controls and in the computer program for controlling elevation.     

模拟冻结法施工环境对大体积混凝土的性能影响

模拟大体积混凝土在冻结法施工环境的状态,将混凝土浇筑7 h后施加?5/60 ℃和?5/70 ℃温差,测试施加模拟环境后混凝土的超声波参数、抗压强度、劈裂抗拉强度、氯离子扩散系数和冲击倾向性,分析混凝土的扫描电镜微观形貌。结果表明,冻结施工环境对于混凝土内部会造成一定的损伤,且平行于加温方向的损伤要大于垂直方向,C50混凝土的损伤大于C70混凝土,温度梯度会加剧混凝土内部的损伤。模拟冻结环境会对混凝土抗压强度、劈裂抗拉强度、氯离子渗透性能和冲击倾向性造成不利影响,温差与性能降低率正相关,且这种影响对于低强度混凝土更加显著。模拟冻结环境造成混凝土试块的内部微观结构不均匀,低温端混凝土结构比较疏松,高温端结构比较致密,导致部分混凝土性能的降低。      

大体积混凝土施工实践

通过热风炉基础施工,介绍了大体积混凝土的施工技术防止混凝土温度裂缝的控制方法。     

混凝土强度等级的验收与评定

结合现行相关规范和实际施工操作的一些经验,对混凝土试件的制作、养护、强度计算及验收评定阐述了混凝土强度的验收与评定,对于施工阶段混凝土强度的评定,应根据混凝土的结构跨度、类型、模板位置等来评定,采用的方法有两种:一种是统计法,另一种是非统计法供施工企业参考应用。     

Effect of Construction Loads and Vibrations on New Concrete Bridge Decks

This paper presents an investigation on the effects of construction loads and vibrations on typical newly poured reinforced concrete bridge decks. The main objective of this paper was to perform dynamic finite-element analyses of concrete bridge decks under construction loads and vibrations. Two types of bridges were modeled by effectively simulating the loads encountered during construction. Separate analyses were performed to simulate one truck as well as two side-by-side trucks. Additional analyses were performed to simulate the loads during construction and pouring sequence. The loads imposed by concrete mixer trucks, including the full concrete load and the load imposed by a trailer unit carrying the pump, were taken into consideration during the modeling of the bridges. The results obtained consisted of vibration modes and frequencies for each structure in addition to top and bottom stresses in each principal direction. A separate analysis was performed that took into account the sequence of pour to determine the effect of moving loads from adjacent traffic and construction loads on fresh concrete. The time history and dynamic analysis indicated that the sequence of pour has a significant effect on the deformation of the concrete at early ages. As a result, the first three mode shapes obtained by the finite-element analysis will be used to optimize sensor locations for future dynamic field testing.     

轻骨料混凝土在筒仓工程中的应用

论述了筒仓工程中以部分轻骨料混凝土代替普通混凝土的应用研究,阐述了轻骨料混凝土在工程应用中的配合比设计方法,并对轻骨料混凝土在筒仓工程中的经济效益提出了一些建议,为工程技术人员和轻骨料混凝土研究人员提供了一些数据参考.     

大体积混凝土施工

现代建筑中时常涉及到大体积混凝土施工,如高层楼房基础、大型设备基础、水利大坝等。混凝土产生温度裂缝,影响结构安全和正常使用,所以必须正确分析并采取措施,来保证施工的质量。     

钻孔灌注桩施工质量的监理控制

钻孔灌注桩属于隐蔽工程,成桩环节多,施工过程容易出现质量事故,监理人员必须重视施工全过程质量监控。本文就钻孔灌注桩施工准备工作、成孔过程、灌注水下混凝土以及事故处理等环节的质量监理程序和关键点质量控制方法进行讨论和分析,提出了保证钻孔灌注桩施工质量的监控措施。     

浅谈混凝土的温度裂缝

经多年的施工监理实践,在查阅有关混凝土内部应力方面的专著后,对混凝土温度裂缝产生的原因、现场混凝土温度的控制和预防混凝土温度裂缝的措施进行阐述。