路用再生骨料水泥混凝土性能研究

拆除旧建筑物产生的原生混凝土经破碎、清洗和分级等加工生成的再生产品可应用于路面结构层、路基防护结构、道路附属设施、路基填筑、市政管线基础及管槽回填等混凝土工程。依据路用水泥混凝土性能要求,对采用各类原生混凝土再生粗骨料制备的不同强度等级的再生骨料水泥混凝土进行了力学性能、碳化性能、抗渗性能、孔结构等试验研究。该研究成果为再生粗骨料的应用提供了一定的参考。     

河道淤泥制备免烧砖试验研究

将河道淤泥替代石硝并外掺一定量的磷石膏制备免烧砖,研究了免烧砖的含水率、吸水率、密度、收缩率、软化系数、抗压强度、抗冻性等性能,分析河道淤泥与磷石膏掺量对免烧砖性能的影响。研究表明:河道淤泥掺量为18%时,免烧砖的各项性能均有所提高,磷石膏的掺入会影响免烧砖的性能,但控制一定量后,可符合GB/T 21144—2007《混凝土实心砖》的要求。     

配制参数对结构轻集料混凝土工作性能及力学性能的影响研究

系统研究了体积砂率和矿物掺合料对轻集料混凝土工作性能及力学性能的影响。研究结果表明:当体积砂率为40%时,轻集料混凝土具有最优的工作性能;粉煤灰单掺可明显改善轻集料混凝土的工作性能,但掺量达到30%以上时对混凝土力学性能有不利影响;复掺10%或20%矿渣粉和10%粉煤灰可制备具有优良工作性能和力学性能的轻集料混凝土。     

废弃混凝土再生粗骨料应用研究

废弃混凝土经预处理、磁性分选、杂物分选、二级破碎或三级破碎、多次筛分等工序制得再生粗骨料,通过测试再生粗骨料和天然粗骨料的物理及力学性能,分析再生粗骨料在混凝土生产上的可行性;采用再生粗骨料替代天然粗骨料制备混凝土,研究分析再生粗骨料的取代率对混凝土工作性能、基本力学性能的影响。     

破碎处理对陶粒及其混凝土性能的影响

采用对比试验的方法研究了破碎处理对页岩陶粒及陶粒混凝土性能的影响,结果表明:通过破碎处理的方式可有效地改善陶粒的级配、减小颗粒粒径、提高筒压强度和堆积密度;使用破碎陶粒配制混凝土可显著提高混凝土的抗压强度,增强抗离析能力,改善工作性能,但对混凝土的热工性能有一定程度的不利影响。     

掺杂商洛钼尾矿制备免烧砖的研究

以商洛钼尾矿为试验矿样、以水泥为胶凝材料进行制作尾矿砖的研究。通过水泥、钼尾矿和减水剂的混合,经搅拌、振动后制备免烧砖,研究钼尾矿添加量对免烧砖性能的影响,并分析尾矿对免烧砖性能影响的机理。结果表明:随着钼尾矿添加量的增大,免烧砖的力学性能下降,当钼尾矿添加量在80%以下时,所制得的免烧砖抗折和抗压强度均在3.86、11.65 MPa以上。不同尾矿添加量所制备免烧砖的密度均在2.3 g/cm3左右。随着养护时间的延长,免烧砖的力学性能提高,养护7 d时,其强度达到了28 d强度的80%以上。     

废瓷粉在混凝土中的应用研究

研究废瓷粉对混凝土工作性能、力学性能及耐久性能的影响。研究表明,废瓷粉能有效改善混凝土粘聚性,但会降低混凝土坍落度及流动性能;掺加5%~15%废瓷粉可提高混凝土力学性能和耐久性能,当废瓷粉掺量超过25%混凝土力学性能和耐久性能均大幅下降;废瓷粉和粉煤灰双掺,混凝土综合性能较好。     

混凝土增效剂在寒旱地区的应用及研究

对混凝土增效剂在西北寒旱地区混凝土中的使用及反应效果进行了试验研究,探讨了混凝土增效剂在高寒干旱地区对混凝土工作性能及力学性能的优化和影响,研究表明,在掺入混凝土增效剂的情况下能显著改善混凝土的工作性能,提高混凝土的力学性能。     

再生水泥混凝土力学性能试验研究

对于再生水泥混凝土,由于其用废弃水泥混凝土破碎的再生集料取代了普通混凝土中的天然集料,所以再生集料的性能成为影响再生水泥混凝土强度的一个最重要的因素。在本课题的研究中,对再生水泥混凝土的主要力学性能进行了试验研究。配制了完全采用再生集料的再生水泥混凝土,并对再生集料的基本物理性能、再生混凝土的工作性和力学性能进行了测试。通过初步的室内试验研究分析了材料特性、水灰比、级配等因素对再生水泥混凝土力学性能的影响,总结了再生水泥混凝土的一些基本性质规律。在此基础上,分析了再生水泥混凝土和普通水泥混凝土在上述方面(主要是力学性能)产生差异的原因。     

建筑废弃物的多元化再生利用

深圳宝安国际机场卫星厅及配套工程建设过程中,产生巨量混凝土固体废弃物。在外运成本高昂、环保政策高压的环境下,通过集成减量化破碎、全自动压砖、再生碎石混凝土及水泥稳定集配等核心技术,将既有混凝土结构、内支撑、桩头等建筑固体废弃物,破碎筛分转换为可回收利用的废旧钢筋、再生免烧砖、再生碎石混凝土及水泥稳定碎石基层等,成功解决巨量建筑垃圾处理成本高、利用率低等难题,实现环境保护和资源再生利用,初步达到建筑固体废弃物零排放的目标。     

Public perceptions of river corridors and attitudes towards river works

The Environment Agency has accepted the need for public participation in decisions concerning river management in keeping with Agenda 21 concerns for environmental policies that command a good measure of public support. In the past, public participation has often relied upon consultations involving formal meetings with interest groups and local politicians. Methods of public consultation are changing. In tapping public opinion the Environment Agency now relies less on public meetings and increasingly more on a direct approach and involvement of the public. Research at Middlesex University is part of the attempt to provide opportunities for the representation of views of the lay public to be considered within the management of rivers and river corridors. The research has used surveys of representative samples of members of the public, often at riverside sites. This paper reports on some of the research projects that have developed on these themes, and analyses the implications of their results for river management and the protection of nature conservation values.     

谈长子县雍河河道治理工程

结合长子县雍河河道的工程实况,从总体布置、堤防工程、险工控导工程、支流入河口防护工程等方面,阐述了雍河河道工程的治理措施,解决了河道现存的一些问题。     

余杭塘河桥主桥设计

以余杭塘河桥主桥设计为背景,采用《MIDAS/CIVIL2006》有限元分析软件,建立该桥的有限元模型,重点介绍了该桥主桥的结构设计与计算,从而使桥梁结构受力均满足规范要求。     

埃姆舍河流域治理模式对汾河治理启示

介绍了德国北威州工业发展历史,从流域治理的角度阐述了埃姆舍河流的基本情况、污染治理过程、治理模式和经验,提出了汾河治理过程中应注意和值得借鉴之处,以改善汾河水环境,实现水资源可持续利用,保障汾河流域社会经济可持续发展。     

谈桃河治理

从宏观的角度概括了桃河的治理与阳泉市发展的关系。从微观的角度介绍了桃河河道淤积，泄洪能力差、河面及其地下污染严重的现状。分析了桃河的气候、水文地质条件和地理特征。阐述了治理桃河不宜设复式槽坝的原因。提出了治理桃河的基本原则和初步设想，以达治理好桃河，美化好阳泉的目的。     

上海地区河道淤泥及淤泥砖性能研究

测试了上海地区河道淤泥的化学组成、矿物组成、热工性能和微观形貌等材料特性。同时还测试了河道淤泥烧结多孔砖的外观性能、物理力学性能和放射性。结果表明,上海地区河道淤泥烧结制成的多孔砖符合GB 13544—2011《烧结多孔砖和多孔砌块》标准要求,能够替代黏土砖使用。     

小环江宜州市境内河段水电梯级开发现状与建议

根据小环江宜州市境内河段概况,描述了河段水电梯级开发现状,总结了开发中存在的问题,并从充分利用河道水能资源的角度提出扩建部分已建梯级的建议,以期在一定程度上缓解该网区电力供需矛盾。     

A model for the frequency of extreme river levels based on river dynamics

A new model for predicting the frequency of extreme river levels is proposed which encapsulates physical knowledge about river dynamics. The central idea is the use of continuous time stochastic processes that use hydrological equations and ergodic theory to model extreme events, rather than relying on statistical fits of classical models to local maximum data. A simple example shows how changes in discharge characteristics change the extreme river level frequencies. Solutions are provided for special cases, and directions for more general techniques are provided.     

Weak acid concentrations and river chemistry in the tovdal river, southern Norway

Water samples were collected weekly from the Tovdal river at Boen in southern Norway over the period August 1978–December 1979, and were analysed for pH, sulphate, chloride, nitrate, sodium, potassium, calcium, magnesium, ammonium, aluminium, dissolved silica and weak and strong acids. During the 16 month study period, the river pH showed a much smaller than normal seasonal variation, ranging from a maximum of 5.14 to a minimum of 4.64. The general pattern of the variation in the concentration of both the atmosphere-derived species (sulphate, nitrate and ammonium) and the ground-derived alkalis (calcium, magnesium and potassium) was a steady increase during the autumn and winter to a broad peak during the spring, followed by a minimum concentration during the summer. Nitrate and ammonium exhibited some differences from this pattern since they are rapidly metabolized. The peak in the concentration of sulphate and nitrate which occurred in the spring of 1979 was matched by an equivalent increase in the alkalis leached from the ground, indicating that ground interactions were rapid during the snow-melt period. In the autumn of 1979, the sulphate concentration increased to values higher than in the previous autumn, and, since the concentrations of the leached alkalis did not increase by an equivalent amount, the pH decreased.The seasonal variation in the measured weak acid concentration also exhibited a late winter/spring maximum and a summer minimum. The measured weak acid concentration is shown to have the theoretical dependence on the aluminium, silica and ammonium concentrations together with a dependence on the total organic carbon concentration. For data from the Langtjern catchment, this dependence was found to be 2.3 μeq mgC⁻¹, and, with a value of 4.75 μeq mgC⁻¹, the theoretical relationship satisfactorily fitted the weak acid data from the Tovdal in the spring of 1977, and was also consistent with the measurements from the present study. The seasonal variation in the measured weak acid content was largely explained by the variation in the concentration of the inorganic weak acid species.     

Urban river design and aesthetics: a river restoration case study from the UK

This paper analyses the restoration of an urbanized section of the River Skerne where it flows through a suburb of Darlington, England; a project which was one of the first comprehensive urban river restorations undertaken in the UK. It is shown how aesthetic values were central to the identification of the River Skerne as a site for restoration, the production of restoration objectives, and a design vision of urban river renewal via restoration. Secondly, the means by which these aesthetic values were realized through the design and implementation of restoration techniques and management operations are described. Finally, it is demonstrated how the resulting aesthetic qualities and overall landscape character were intended to accomplish a set of interrelated policy goals.