改性环氧修复剂修复潮湿环境下混凝土裂缝的固化时间影响

利用室内试验的方式,探讨了固化时长对不同宽度衬砌混凝土裂缝的修复效果。试验结果显示,修复之后混凝土试件的抗压强度、抗折强度和渗透性均有显著提升。结合试验结果和工程的经济性,建议在工程实践中选择9 d固化时长。

改性环氧修复材料在渠道衬砌板潮湿界面的修复性能试验

衬砌混凝土板开裂是影响输水渠道服役性能和耐久性的重要因素,而对其进行有效修复是学界和工程界关注的重要领域。此次研究针对输水渠道衬砌结构的特殊服役环境,提出了一种针对潮湿环境混凝土裂缝的改性环氧修复材料。试验结果显示,该材料可以获得良好的修复效果和耐久性,建议在衬砌修复工程中选用。同时,根据试验结果,建议施工中采取不小于14 d的固化时间。

渗透修复型环氧在水泥混凝土桥面裂缝修复中的应用

水泥混凝土桥面裂缝是一种常见病害,其修补材料应具有高渗透性、高强度、无苛刻施工条件、修补快速等特点,以某混凝土桥面裂缝处理工程为例,阐述渗透修复型环氧基层处理剂材料性能特点与施工流程,结论表明渗透修复型环氧基层处理剂在渗透性、成型强度、强度成型速度、施工易行性及修补效率上具有突出优势,适用于水泥混凝土裂缝修补作业。

新型快速修补材料MRK在某桥梁病害修复项目中的应用

介绍了环氧类快速修复材料MRK在广清高速广州连接线桥梁伸缩缝加铺层病害修补中的应用,并对其力学性能、粘结性能、高温及水稳定性等进行了研究,结果表明各项性能优良,对伸缩缝加铺层病害的修补效果良好。

南水北调万年闸泵站渠道衬砌施工方案比选

近几年,南水北调万年闸泵站渠道衬砌板表面陆续出现爆皮、砂浆及碎石脱落等现象,为保证工程运行安全,需对其维修处理。根据水利工程多年工程维修经验,结合多方咨询及调研,确定采用环氧修复和拆除重建两种方案对比施工,解决输水渠道冻融剥蚀等问题,同时做好人、材、机投入数量统计,为后续类似工程维修积累经验。

Lubricant Biodegradation Enhancers: Designed Chemistry and Engineered Technology

In recent decades, a growing worldwide trend of developing the biodegradable lubricants has been prevailing to form a specific field of green chemistry and green engineering. Enhancement of biodegradability of unreadily biodegradable petroleum-based lubricants has as such become an urgent must. For over a decade the authors have been focusing on the improvement of biodegradability of unreadily biodegradable lubricants such as petroleum-based lubricating oils and greases. A new idea of lubricant biodegradation enhancer was put forward by the authors with the aim to stimulate the biodegradation of unreadily biodegradable lubricants by incorporating the enhancer into the lubricants in order to turn the lubricants into greener biodegradable ones and to help in situ bioremediation of lubricant-contaminated environment. This manuscript summarizes our recent efforts relating to the chemistry and technology of biodegradation enhancers for lubricants. Firstly, the chemistry of lubricant biodegradation enhancers was designed based on the principles of bioremediation for the treatment of hydrocarbon contaminated environment. Secondly, the ability of the designed biodegradation enhancers for increasing the biodegradability of unreadily biodegradable industrial lubricants was investigated through biodegradability evaluation tests, microbial population analysis, and biodegradation kinetics modeling. Finally, the impact of biodegradation enhancers on some crucial performance characteristics of lubricants such as lubricity and oxidation stability was tested via tribological evaluation and oxidation determinations. Our results have shown that the designed chemistry of nitrogenous and/or phosphorous compounds such as lauroyl glutamine, oleoyl glycine, oleic diethanolamide phosphate and lauric diethanolamide borate was outstanding in boosting biodegradation of petroleum-based lubricants which was ascribed to increase the microbial population and decrease the oil-water interfacial tension during the biodegradation process. Lubricants doped with the biodegradation enhancers exhibited much better biodegradability and higher biodegradation rate in the surrounding soils which could be well modeled by the exponential biodegradation kinetics. Furthermore, as lubricant dopants, the biodegradation enhancers also provided excellent capability in reducing friction and wear and in retarding oxidation of lubricants. In the nature of things, lubricant biodegradation enhancers, which are multi-functional not only in the improvement of biodegradability, but also in the fortification of lubricity and in the inhibition of oxidation of lubricants, are expected to be promising as a new category of lubricant additives.

Phytoremediation of PAH-Contaminated Sediments by Potamogeton Crispus L. with Four Plant Densities

In order to investigate the effect of plant density ofPotamogeton crispus L. on the remediation of sedi- ments contaminated by polycyclic aromatic hydrocarbons, a 54-day experiment with four plant densities （642, 1 604, 2 567 and 3 530 plants/m^2） was conducted. The results showed higher plant density with slower plant growth rate. Surface area per plant was the most sensitive root parameter to plant density. At the end of the 54-day experi- ment, planting P. crispus enhanced the dissipation ratios of phenanthrene and pyrene in sediments by 6.5%-26,2% and 0.95%-13.6%, respectively. The dissipation increment increased with increasing plant density. Plant uptake accounted for only a small portion of the dissipation increments. Furthermore, P. crispus could evidently improve sediment redox potentials, and strong positive correlations between root surface area and the redox potential as well as between the redox potentials and the dissipation ratios of phenanthrene and pyrene were obtained, indicating that the oxygen released by the roots ofP. crispus might be the main mechanism by which P. crispus enhanced the dis- sipation of PAHs in sediments.

Photocatalytic remediation of ionic pollutant

Recently, the photocatalysts have attracted lots of attention and efforts due to their great potential for environmental remediation application. Toxic ions in water are an increasing environmental pollutant with the fast development. Numerous researches have been made to develop photocatalysts to treat ionic pollutants under the illumination of ultraviolet light and visible light. Here, photocatalytic remediation of toxic ionic pollutants has been reviewed. This review summarized and discussed various photocatalysts including TiO〉 modified TiO2, metal oxides, metalsulfides, and nitrides and their recent progress in removing ionic pollutants such as heavy metal ion. The latest achievements and their future prospects of photocatalytic remediation of ion pollutant have also been reviewed.