Rheology and conduction calorimetry of cement modified with calcined paper sludge

This paper considers calcined paper sludge as an alternative source of metakaolin, an established supplementary cementitious material. Calcination of the sludge generated in the recycling of newsprint paper at 700 °C yields a product with pozzolanic properties. The effects of this recycled metakaolin on the rheology and conduction calorimetry of cement pastes have been studied and compared to the effects of commercial metakaolin. The effects are similar and the results show that calcined paper sludge has the potential to be used as a supplementary cementitious material. This offers a route for utilising this waste material, as an alternative to the increased environmental burden associated with the production of metakaolin from natural kaolinite resources.     

焊接无头轧制技术

阐明近几年开发出来的一种高效、低成本焊接无头轧制新技术,它包括无头轧制和焊接多块小方坯轧制二种技术,并对闪光焊机和二种焊接轧制的优缺点、经济效益和可行性进行了分析和比较 ,表明这是一种改变现有轧制生产方式的一种重大革新。     

混凝土灌注桩在软弱复杂地基中的应用

针对混凝土灌注桩对软弱复杂地基的处理及应用，结合具体实例介绍了混凝土灌注桩施工方法的设计与施工过程。从经济、技术、工期、施工难易程度等多方面阐述了该施工方法的优点，同时还指出在施工过程中应注意的要点，并提出应采取的措施，证明该方法值得推广和应用。     

绿色印染助剂的开发与原料选用

指出了印染助剂中被禁用的非环保助剂的致癌、天才畸、生物降解性差等危害性，同时详细介绍了无毒性、生物降解性好的替代产品及原材料的选用，以予科技人员进一步开发符合环保要求和生态指标的绿色印染助剂。     

宝珠寺水电站13号～21号坝段大坝中热水泥帷幕灌浆

本文从分析帷幕灌浆设计入手，着重介绍了帷幕灌浆施工工艺和质量检查；通过测试数据对灌浆效果进行了评价分析，认为通过大坝中热水泥高压灌浆，河床坝基幕体已基本形成。     

保温隔热材料的新进展

介绍了国内外最新发展的几种具有代表性的保温隔热材料 ,分析了各种材料和保温隔热性能 ,讨论了材料的组分、配制、施工工艺、工程应用及发展前景等。     

On morphometric uniformity of diamond micron powders

The paper presents the findings of characterization of initial diamond powders and products of their flotation separation, analysis of the adequacy of mean values of morphometric characteristics and assessment of powder uniformity by a system-criterion method. The separation is demonstrated to provide a significant improvement of powder uniformity in dimensional characteristics and shape index. The flotation products have been found to feature the best uniformity which explains their higher abrasive ability. The flotation separation method has proved to be a suitable tool for improving morphometric uniformity of diamond micron powders, and the proposed system of computer-aided analytical methods has been demonstrated to offer an efficiency means for quantitative analysis of morhometric characteristics of the powders.     

Microstructural properties of the bulk matrix and the steel/cement paste interface in reinforced concrete,maintained in conditions of corrosion and cathodic protection

Although rarely considered, especially within the investigation of steel corrosion phenomena or electrochemical protection techniques in reinforced concrete structures, the concrete bulk matrix has a significant contribution in the global performance of the system “reinforced concrete.” This is especially the case when chloride‐induced corrosion or electrical current flow [as within impressed current cathodic protection (CP)] are involved. In the latter cases, the concrete bulk matrix undergoes significant alterations in chemical composition, electrical properties, and microstructures, thus influencing the overall performance of the system. This work reports on the microstructural investigation of the bulk concrete matrix and the steel/cement paste interface in reinforced concrete, previously subjected to corrosion and CP for 460 days. The emphasis hereby is to evaluate the altered structural properties, i.e., porosity, pore size, permeability of the bulk cement matrix, and the steel/cement paste interface (translated to bond strength) as a result of chloride‐induced corrosion and two types of CP (conventional and pulse), compared to control (non‐corroding, non‐protected) conditions. The research revealed a major contribution and close dependence of all microlevel interfaces on the global performance of reinforced concrete. The electrical current flow (as in CP applications) was found to bring about unfavorable modifications to the material structure, both in the bulk matrix (reducing porosity) and at the steel/cement paste interface (enlarging interfacial gaps). The derived microstructural parameters show that the conventional CP leads to a higher level of structural heterogeneity, whereas the pulse CP exerts minimal or no effects, maintaining the material properties close to the reference (control) conditions, the underlying mechanism being a more homogeneous material microstructure.