摘 要：分析了湖南区域三个混凝土预拌厂废水的理化性质，采用该废水制备了C20~C60混凝土来研究废水对混凝土工作性能、力学性能和关键耐久性能的影响，并在相关指标满足工程应用的要求后，将其应用于工程中。研究表明，三个预拌厂产生的废水及其沉淀废渣各项理化性质相似，成分接近，主要以SiO2、Al2O3和CaO为主。沉淀废渣粒径较小可以改善混凝土体系的颗粒级配；各强度等级的混凝土在废水的最优掺量上存在差异，C30混凝土废水掺量在50%表现出较为优异的工作性，且废水对于中高强度等级混凝土的抗压强度未发现不利的影响；废水可降低混凝土的电通量和提高抗碳化性能，C60废水混凝土6 h总电通量为300 C左右，碳化深度随着废水掺入量的增加而减少。 bstract: According to physical and chemical properties analysis of three concrete mixing stations in Hunan area, the C20~C60 concrete were prepared by adding waste water to study the effects of waste water on working performance, mechanical performance and critical durability of the concrete. The concrete was applied to engineering after relevant indicators met the requirements. The results show that physical and chemical properties of the waste water and sediment residue produced by the three mixing station are similar, and the main composition is SiO2, Al2O3 and CaO. The small particle size of sediment residue can improve the particle gradation of concrete. The concrete with different strength grade has different optimal content of waste water. The 50% waste water content of C30 concrete has excellent working performance, and waste water has no adverse effect on the compressive strength of medium and high strength grade concrete. Waste water can reduce concrete electric flux and improve carbonation resistance. The 6 h total electric flux of C60 concrete by waste water is about 300 C, and the carbonation depth decreases with the increase of the content of waste water.

摘 要：将废弃混凝土破碎制备再生骨料应用于透水混凝土中，通过四因素三水平正交试验研究了骨料粒径、集灰比、水胶比、水泥用量四个因素对再生骨料透水混凝土性能的影响。结果表明，影响透水混凝土性能的因素依次为骨料粒径＞水泥用量＞集灰比＞水胶比，水胶比在0.27~0.35范围内对再生透水混凝土性能无显著影响。选取正交试验中强度和透水系数最高的两组分别研究再生骨料掺量对透水混凝土性能影响，结果表明，再生骨料在透水混凝土中的掺量不宜超过50%。 Abstract: Recycled aggregate made by crushed deserted concrete was used to prepare pervious concrete. The orthogonal experiments of four factors and three levels was carried out to study influence of aggregate size，aggregate-binder ratio，water-binder ratio, cement content on the performance of pervious concrete. The results show that the contribution of factors which affect the performance of pervious concrete is aggregate size＞cement content＞aggregate-binder ratio＞water-binder ratio. The water-binder ratio has no significant effect on the performance of recycled pervious concrete in the range of 0.27~0.35. The two groups with the highest strength and permeability coefficient in the orthogonal test are selected to study the effects of recycled aggregate content on the performance of pervious concrete, result shows the content of recycled aggregate in pervious concrete should not exceed 50%.

摘 要：通过高层泵送顶升施工钢管混凝土配合比设计与应用，阐述了顶升混凝土配制关键技术，同时通过对顶升混凝土全面质量控制管理，取得了大量基础数据，总结了顶升混凝土的质量控制要点，可为顶升混凝土配制和顶升施工过程质量控制提供参考。 Abstract: Through the mix ratio design and application of high-rise pumping lift-up construction concrete filled steel pipe, the key technologies of concrete for pumping lift-up construction are described. At the same time, through the comprehensive quality control process for the concrete, a large amount of basic data is obtained, and the quality control of jacked concrete is summarized. The main points can provide a reference for the quality control of pumping lift-up concrete preparation and construction proc

摘 要：磷石膏是生产工业磷酸等的副产物，通常，磷石膏在水泥水化硬化中可起缓凝作用。本文基于低场核磁共振法这一无损检测方法，研究磷石膏的掺入对水泥在水化硬化过程中引起的早期孔结构的变化。结果表明，随着磷石膏的加入，水泥硬化体中的孔径分布逐渐向较小尺寸的方向进行发展；水泥硬化体的最可几半径不仅随养护龄期的增加而逐渐降低，随磷石膏掺量的增加而逐渐增加。基于分形理论研究了在该过程中水泥硬化体的孔径分布的变化，结果表明，其分形维数随养护龄期的增加而逐渐降低，随磷石膏掺量的增加而逐渐降低。 Abstract: Phosphogypsum is a by-product of the production of industrial phosphoric acid. Generally speaking, phosphogypsum plays a retardation role in hydration and hardening of cement. A new nondestructive testing method based on low field nuclear magnetic resonance (NMR) method was used to study the changes of pore structure in the early stage caused by the incorporation of phosphogypsum on cement in the process of hydration and hardening. The results show that with the addition of phosphogypsum, the pore size distribution of hardened cement gradually developed to a smaller size. The most probable radius of hardened cement paste decreases with the increase of curing age and increased with the increase of phosphogypsum content. Based on the fractal theory, the variation of the pore size distribution of the hardened cement paste in this process is studied. The results show that the fractal dimension decreased gradually with the increase of curing age, and gradually decreases with the increase of the amount of phosphogypsum.

摘 要：针对目前设计的立式径向挤压制管机成型头，采用SolidWorks软件建立不同拔模斜度的成型头三维模型，运用Hypermesh软件对各模型进行前处理，通过LS-Dyna计算各成型头挤压混凝土成型的力学行为，分析了拔模斜度对混凝土最大应力和应变的影响，拟合出了拔模斜度与混凝土最大应力、应变的关系曲线，确定混凝土成型效果最佳时，成型头的拔模斜度为2.1 °。在此条件下，基于数值模拟和正交实验，分析了成型头上升速度、上挤压辊顺时针旋转速度、下挤压辊与抹光环逆时针旋转速度对混凝土成型效果的影响，确定了最佳的工艺参数组合：成型头上升速度为0.1 m/s，上挤压辊顺时针旋转速度为60 r/min，下挤压辊与抹光环逆时针旋转速度为140 r/min。 Abstract：The molding head of vertical radial press concrete pipe machine was designed. The SolidWorks software is used to model the different draft angle molding heads, and the HyperMesh software is used to establish the finite element model of each molding head. The Ls-Dyna is used to calculate the mechanical behavior of molding head extruding the concrete to analyze the effect of draft angle on the stress and strain of concrete. From the fitted curve of draft angle and the stress and strain of concrete, the molding results of the concrete are the best when the draft angle of molding head is 2.1 °. Under this condition, based on the numerical simulation and orthogonal experiment, the effects of the rising speed of the molding head, the clockwise rotation speed of the upper roller and the counterclockwise rotation speed of the lower roller on the molding results of the concrete are analyzed. The best combination of process parameters is that the rising speed of the molding head is 0.1 m/s, the clockwise rotation speed of the upper roller is 60 r/min and the counterclockwise rotation speed of the lower roller is 140 r/min.

摘 要：以流动度为控制指标，讨论了纤维素醚掺量和分子量变化对脱硫石膏基自流平砂浆性能的影响，测试了纤维素醚对脱硫石膏水化热的影响规律。试验结果表明，纤维素醚掺量和分子量的增加，显著增大了砂浆的黏度和保水性，同时，凝结时间延长，力学性能呈下降趋势，相较而言，分子量的增加对砂浆宏观性能的影响小于掺量的变化。在相同流动度时，纤维素醚掺量增加导致的用水量增加和体积密度的下降是砂浆力学性能下降的主要原因。 Abstract: The effect of the content and molecular weight of cellulose ether on the basic properties of desulphurized gypsum based self-leveling mortar was discussed, and the effect of cellulose ether on hydration heat of desulphurized gypsum was tested. The experimental results show that the increase of cellulose ether content and molecular weight significantly increases the viscosity and water retention of mortar. At the same time, the setting time is prolonged, and the mechanical properties of mortar decrease. The increase of molecular weight has less effect on the macroscopic properties of mortar than the change of content. At the same fluidity, the increase of water consumption and the decrease of volume density caused by the content of cellulose ether are the main reasons for the decrease of mechanical properties of the mortar.