北京西长安街大修使用新型预拌快硬混凝土

北京西长安街大修工程前不久开工建设。大修工程范围西起五棵松桥,东至南礼士路,全长6.88km。此次大修工程采用预拌硫铝酸盐水泥快硬混凝土,北京市政路桥高强公司被业主单位公联公司指定为独家供应单位。此次大修完成后将提高车辆行驶的安全性及舒适性,为2014年APEC峰会的召开提供有力的交通保障。     

钢纤维快硬硫铝酸盐水泥混凝土性能研究及在桥梁伸缩缝改造工程中的应用

本文介绍了以预拌方式应用快硬硫铝水泥配制钢纤维特快硬混凝土的研究和应用。指出配制该快硬混凝土的关键是要解决新拌混凝土的凝结时间和可工作时间之间的矛盾，在试配中要考虑快硬硫铝酸盐水泥专用外加剂的组成和掺量以及混凝土中粉煤灰与专用外加剂的适应性问题；在拌制、运输、浇筑和养护等一系列环节，要严格遵循有关注意事项方能确保混凝土工程质量。     

钢纤维硫铝酸盐水泥混凝土性能与工程应用研究

以预拌方式用快硬硫铝水泥配制钢纤维混凝土，其关键是要解决新拌混凝土的凝结时间和可工作时间之间的矛盾。在试配中要考虑快硬硫铝酸盐水泥专用外加剂的组成和掺量以及混凝土中粉煤灰与专用外加剂的适应性问题；在拌制、运输、浇筑和养护等过程中，要严格遵循有关注意事项以确保混凝土工程质量。     

新型材料在北京长安街路面大修工程中的应用

结合北京长安街路面大修工程的特点,介绍了长安街路面大修工程中抗车辙沥青混合料、橡胶沥青混合料、温拌沥青混合料、温拌橡胶沥青混合料、钢渣沥青混合料、煤矸石沥青混合料及快硬水泥混凝土等资源节约型和环境友好型新型材料的应用。     

特快硬水泥混凝土的性能与应用

特快硬混凝土是以硫铝酸盐超早强水泥为主,掺加外加剂配制而成的。它具有快硬、早强、凝结时间可调节,后期强度无倒缩、抗硫铝酸盐侵蚀等特点。特快硬混凝土的施工基本上与普通水泥混凝土相似,由于它具有快硬、早强等特点。因此,可以用于紧急抢修工程,快速施工工程、喷射混凝土施工工程等。     

混凝土外加剂对硫铝酸盐水泥水化历程的影响

采用x射线半定量分析方法研究了在快硬混凝土中掺加缓凝剂和促硬荆对硫铝酸盐水泥凝结时间、水化历程、水化产物种类的影响.结果表明:快硬硫铝酸盐水泥的水化产物主要有Aft、Afm、C4H13及Al(OH)3,而C2S的水化非常缓慢;快硬硫铝酸盐水泥快凝早强的主要原因是Aft的生成,而后期强度发展停滞甚至倒缩的原因主要是Aft...     

市政改造工程快速修补技术获公路学会一等奖

一项专门针对城市应急抢险工程,特别适合要求限时开放交通的城市市政改造工程的高效快速修补技术—硫铝酸盐水泥在应急抢修钢筋混凝土工程中的应用控制技术最近获北京公路学会一等奖。该项技术以预拌方式利用硫铝酸盐水泥来配     

科技信息

快硬早强混凝土应用于长安街大修改造工程由北京市政路桥控股下属建材集团高强公司研发并拥有拥有自主知识产权的快硬早强混凝土产品近期成功应用北京长安街大修改造工程。快硬早强混凝土规模化生产供应难度非常大,世界范围内尚无可参考的成功范例。快硬早强混凝土运达现场后必须在0．5h内进行振捣、成型抹面及养护,     

应用快硬硫铝酸盐水泥浇筑设备基础的问题与讨论

快硬硫铝酸盐水泥是一种新的水泥品种,它具有活性高、水化速度快、水化产物比较稳定、早期强度高、抗冻性能好等优点,所以它特别适用于冬期抢建的混凝土工程;但由于快硬硫铝酸盐水泥水化放热量的70～80％集中在第一天,则成为混凝土产生温度裂缝的根源,从而限制了其适用范围。本文通过分析总结怏硬硫铝酸盐水泥浇筑设备基础(或大体积混凝土)的应用,提出了一些探索性见解。     

浅议水泥性能对预拌混凝土品质的影响

文中重点探讨了水泥需水性、水泥细度、水泥凝结时间、同外加剂适应性及对预拌混凝土成本、质量的影响,提出了预拌混凝土应采用需水性小、细度控制合理、凝结时间稳定正常、同外加剂适应良好的新型干法水泥生产线生产的水泥作胶凝材料。     

干旱区绿洲环境下的新疆小城镇建设投资

一、研究区域基本现状新疆地处欧亚大陆腹地,地貌轮廓表现为“三山夹两盆”,山地与平原的面积大致各占50%,镶嵌于戈壁沙漠的绿洲仅有7万平方公里。新疆土地面积166.49万平方公里,占全国总面积的六分之一。气候干旱,荒漠广布,是中国最大的干旱区,是亚洲干旱核心区,也是世界上著名的干旱区之一。水资源短缺,生态极度脆弱。新疆2004年底有1950万人,人均GDP已经超过了1000美元,城镇化进入了快速发展阶段,特别是小城镇的发展速度较快。但新疆特殊的干旱区绿洲环境,使得小城镇的发展存在许多问题。一是城镇规模小而散,基础设施配套差,城镇集散和…     

污泥制砖存在问题浅析

污泥制砖符合国家的环保政策,但在技术方面还待进一步创新和突破。为此分析了污泥制砖在技术方面、环保方面和社会大众认可方面存在问题及相应的改进措施。     

Levels of manganese in the urine of female farmers in non-polluted regions in Japan

Nearly 1500 urine samples were collected from female farmers in eight regions widely scattered in the islands of Japan in the winter of 1987-1988. The samples were analysed for manganese by wet ashing and flameless atomic absorption spectrophotometry under strict quality control. The values observed after adjustment for a specific gravity of 1.016 were distributed log-normally with a geometric mean of 0.65 microgram/l and a geometric standard deviation of 2.47. There was no effect of aging or any effect of smoking on the urinary manganese concentration. The inter-regional difference may be present but not yet conclusive. As no sex difference was observed in a previous study, it may be possible to deduce that the value may possibly stand for the "background" level of both men and women, either smoking or non-smoking, among the general Japanese population. The observed value is discussed in comparison with values reported in the literature.     

Typification of Fires in Buildings in Spain

Although the Dirección de General de Protección Civil (DGPC), an agency of the Spanish government, has been responsible for the collection of data and the statistical analysis of fires since 1985, it has not as yet issued any reports. It is true that a couple of studies have been made, but in neither case did they use a standardized methodology but relied simply on the heterogeneous information provided by the fire brigades which cooperated in the studies. At that time Spanish fire brigades did not have special units for professional fire investigation, nor was the information derived from standardized methodologies suited to research purposes. In addition, information was extremely scarce and basic, focussed only on the fire, the use of the building and personal data of the victims. In this context, the project for a Fire Investigation Unit in the Fire Brigade of Málaga (the sixth largest Spanish province in inhabitants) was set up. Although inspired in the methodologies used in the USA and in the UK, the aim was to create a customized methodology for the first scientific investigation of fires in Spain. Our research was conducted in 2007. Using the methodologies of the USA and the UK, our own methodological approach and the Spanish regulations, we drew up a questionnaire with 110 variables arranged into 6 modules. We studied 96 fires out of the 154 emergency fire calls received in 2007, having omitted some emergency calls for various reasons. Our results revealed that it was necessary to generalize the installation of fire extinguishers in residential buildings, to train the general public in the use of these devices, to promote the use of fire and smoke detectors in residential buildings, to encourage the inspection and control of old electric installations and to monitor the new installations, to generalize the implementation of emergency and evacuation plans and to design new systems and materials for the cabinets where hand-held extinguishers are stored.     

莳花在城市绿化中的应用

目的:花化、香化、彩化已成为城市园林绿化的主要趋势,也是为满足人们对环境要求越来越高的一种心境。方法:选择采用莳花能表现出品种繁多,色彩艳丽等不同的方式,从而能在很大程度上丰富了植物造景的层次感要求。结果:能使其达到美化环境、增添节日气氛、提高绿化品质等方面有着突出的作用。结论:莳花造景对城市的美化可达到立杆见影效果,从而提高城市的形象和品位。     

分光光度法测水中余氯

介绍了用双硫腙分光光度法测定水中余氯的新方法，阐述了其测定试验过程，根据试验结果显示，其结论符合国家标准，表明该方法可用于自来水等样品中余氯含量的测定，结果比较准确。     

Intersections of inequality in homeownership in Sweden

Abstract

Inequalities relating to ownership of housing have become a major issue de jour in many Western societies. This article examines how the distribution of homeownership in Sweden relates to two factors widely seen as significant to such inequalities, namely parental tenure status and place of birth. We use longitudinal registry data to examine the bearing of these two factors on individual-level tenure progression since the beginning of the 1990s for persons at different stages of their housing careers. We extend existing understandings of Swedish homeownership patterns by demonstrating that inequalities relating to place of birth and parental tenure intersect with one another in ways that substantially advantage certain subgroups while disadvantaging others, and by demonstrating that experiences of entry into homeownership have in recent years been changing in markedly different ways for these different subgroups. Overall, Swedish homeownership inequalities, far from dissipating, appear to be hardening along existing lines.     

遗传算法在边坡稳定系数计算中的应用

边坡稳定性的关键问题是确定最危险滑动面(潜在最危险滑动面)和边坡的稳定系数。国内外一般是采用先假定边坡滑移模式,然后近似确定最危险滑动面,再求近似的边坡稳定系数的方法来分析边坡的稳定性,但假设的边坡滑移模式难以反映边坡滑移的实际状态。因此本文探索利用遗传算法搜索最危险滑动面,并得到最小稳定系数及对应的最危险滑动面曲线,取得了较好的效果。     

日本城市浅层地下空间利用的新成就

本文结合日本川崎市站前广场和神户市哈巴兰德地区的立体化再开发，分析介绍当前日本浅层地下空间开发利用的成就和特点。     

地质情况复杂地区高速公路隧道地质预报研究

针对地质情况复杂地区垫邻高速公路设计、施工中的具体问题，从地质预报的方法、原理方面入手，对地质情况复杂地区高速公路隧道施工中的地质超前预报工作进行了深入的研究，在分析归纳的基础上，提出合适的工作方法。