废旧橡胶颗粒改性水泥混凝土及其工程应用

阐述了废旧橡胶的应用现状及废旧橡胶颗粒改性水泥混凝土的特性,分析了废旧橡胶改性水泥混凝土需要进一步探讨的问题,展望了废旧橡胶颗粒改性水泥混凝土的应用前景。研究表明:与传统水泥混凝土相比,废旧橡胶颗粒改性水泥混凝土具有明显的优越性,将大大拓展混凝土材料的应用领域。     

粉煤灰掺量对砂浆固化氯离子性能的研究

主要研究了粉煤灰掺量对砂浆固化氯离子性能的影响，结果表明：随着粉煤灰掺量的增加，混凝土固化氯离子的能力增强，主要是对Cl-的化学结合能力增强，粉煤灰掺量达到60％时，化学结合能力和物理吸附能力都大幅度增大。     

氯盐环境下桥梁混凝土结构的腐蚀行为及破坏机理

为了解决氯盐导致钢筋混凝土结构耐久性破坏的问题,通过测试处于氯盐侵蚀环境中混凝土内部Cl-含量、pH值及含碱量的分布规律,探讨了氯盐对混凝土结构的腐蚀行为和破坏机理;揭示了氯盐侵蚀下钢筋混凝土曲线桥梁过早劣化的机理,并对此类病害的防治及治理提出了合理建议。结果表明：干湿循环条件下,大量Cl-侵入混凝土内部并且到达钢筋表面,造成钢筋锈蚀、混凝土胀裂,且随Cl-含量增加,混凝土PH值下降,含碱量增大;在含有Cl-的区域,混凝土PH值均降低;氯盐入侵后,增大了混凝土碱骨料破坏的可能性,混凝土内部孔结构发生了明显粗化。     

Long-term durability of cement-based materials with very low <Emphasis Type="Italic">w/b</Emphasis>

To investigate the durability, especially the long-term stability of cement-based materials with very low w/b, the air permeability test, carbonation test, capillary absorption rate test and dilation potential test were adopted under long-term heat treatment condition. Microstructure of these materials is also analyzed by scanning electronic microscopy （SEM） and mercury intrusion porosimeter （MIP） in order to further unveil its mechanism and interrelation between microstructure and its properties. The results indicate that in the area investigated, cement-based material with w/b 0.17, like RPC, possesses low porosity and excellent durability. Moreover, its porosity will further decrease under long-term heat treatment compared with normal heat treatment. Its long-term durability is much superior to that of other cement-based materials with w/b 0.25 or 0.35 as high strength concrete（HSC）.     

Invading track of chloride ions in cemented-based materials

Invading track of chloride ions and chloride ion distribution rule in cement-based materials were investigated by partially soaking in 3.5% (mass fraction) NaCl solution and fully immerging in 3.5% and 5.0% (mass fraction) NaCl solution, respectively, and relevant invading mechanisms were discussed. Results indicate that under full immerging condition, the invading track of chloride ions in cement mortar is similar to beeline that is vertical to chloride ion invading direction, and chloride ion content decreases rapidly with the increase of chloride ion invading depth. Under partial soaking condition, the invading track of chloride ion in cement mortar is similar to the shape of concave parabola, and chloride ion content decreases slowly along the lengthway direction of cement mortar samples in the distance of 20-80 mm from the bottom. Lots of chloride ions accumulate in cement mortar surface layer under the effect of capillary rise and evaporation and then invade cement mortar by diffusion effect. Under partial soaking condition, cement mortar is distinguished by four areas, i.e., immerging area, wet area, crystallization area and dry area.     

CFG桩混合料的强度影响研究

研究了水胶比、胶凝材料用量、粉灰比、龄期等因素对CFG桩混合材料的强度影响规律.结果表明:水胶比、粉灰比及胶凝材料用量对CFG桩混合料的抗压强度存在明显影响;随着龄期的增加,CFG桩混合料的抗压强度增大,且其28d 龄期后的抗压强度增长率较大.在保证工作性的务件下,CFG桩混合料的胶凝材料用量宜取低限值.     

粉煤灰－硅灰双掺蒸养混凝土配制技术研究

将Ⅰ级粉煤灰与硅灰复合 ,研究双掺掺合料蒸养混凝土配制方法。试验表明 :通过控制混凝土拌合物的沉落度 ,优化胶凝材料用量和掺合料掺配比 ,采用适宜水量 ,可配制出强度满足预应力混凝土轨枕技术要求的C60蒸养混凝土 ,其抗冻性能能满足F3 0 0要求     

粉煤灰掺量和细度对水泥凝结时间的影响

研究了不同掺量、不同细度的几种粉煤灰对水泥凝结时间的影响。结果表明，粉煤灰对水泥凝结时间有很明显的延缓作用，并且其延缓程度随粉煤灰掺量的增加而增大，而粉煤灰的细度对水泥凝结时间的影响不显著。     

钢管混凝土拱桥施工中的计算机辅助方法

钢管混凝土拱桥因美观的外型和优良的材料性能而受青睐。由于钢管混凝土拱桥施工中拱肋的线形控制及应力状态复杂，所以是控制的重点和难点。在线性控制方面，钢管拱肋的加工及拱肋梁段的拼装是线性控制的基础和能否顺利施工的保证。为了保证钢管拱肋的线形，传统采用现场预拼的方法。现场预拼对场地条件要求高，耗时耗钱，施工对拱肋段损伤大，有时根本无法实现全跨预拼。所以，亟需一种快捷的方法对加工质量进行检验和拼装模拟；在混凝土灌注施工中，钢管拱的结构刚度随着加载施工不断变化，稍有不慎就可能引发工程事故。为了保证施工安全，提高灌注质量，必须进行应力测试与监控。本文试图通过衡南桥施工控制中利用计算机辅助线形检测及预拼装模拟和运用计算程序模拟加载分析，优化加载程序，介绍一种在钢管混凝土拱桥施工过程中的计算机辅助施工方法。     

矿物掺合料对新拌水泥浆体密实性能的影响

采用浆体相对密实度（d/d0)指标，定量分析了超细磨粉煤灰，磨细矿渣及硅粉这三种矿物掺合料对新抖水泥浆体密实性能影响的规律，研究了掺矿物掺合料的水泥浆体流动性与相对密实度的关系以及新抖水泥浆体相对密实度对水泥胶砂抗压强度的影响，并进一步阐明了矿物掺合料对水泥浆体的物理填充作用。