摘 要：选择4.75~1.18 mm、1.18~0.3 mm及0.3 mm以下三个级配的再生细骨料，采用Fuller法、K法和i法进行三级配再生细骨料的组成设计，研究了不同级配组成的再生细骨料对自流平砂浆强度的影响规律。结果表明，三种不同粒径的再生细骨料， Fuller法获得的级配组成中小颗粒较多，K法得到的级配组成中小颗粒较少；而三种方法得到的最佳级配组成所对应的砂浆强度中，Fuller法的抗压强度和抗折强度均最小，i法的强度最高，且在抗压强度与K法相近的同时表现出更高的抗折强度。最终认为，i法适合本实验再生细骨料的级配组成设计。 Abstract: In order to study the effect of recycled fine aggregate gradation on strength of self-leveling mortar, the gradation is designed by three methods of Fuller method, K method and i method, using three recycled fine aggregates whose gradation is 4.75~1.18 mm, 1.18~0.3 mm and under 0.3 mm. The results show that there are the most small particles in the gradation obtained by Fuller method and the least small particles in the gradation obtained by K method. The compressive strength and flexural strength of the mortar obtained by Fuller method are the smallest, the compressive strength obtained by i method is similar to that obtained by K method, but the flexural strength is higher than that obtained by K method. The i method is suited to design the gradation of recycled fine aggregate used in self-leveling mortar.

侯云芬,郑东昊,周文娟.再生细骨料级配对自流平砂浆强度的影响[J].混凝土与水泥制品,2019(7):96-100. HOU Y F,ZHENG D H,ZHOU W J.The Influence of Recycled Fine Aggregate Gradation on Strength of Self-leveling Mortar[J].China Concrete and Cement Products,2019(7):96-100.

摘 要：为了进一步强化再生骨料、改善再生骨料混凝土的性能，研究了纳米碳化硅改性水玻璃对再生骨料的强化效果，并分析了作用机制。结果表明，纳米碳化硅改性水玻璃对再生骨料的强化作用明显，但会受水玻璃浓度和纳米碳化硅掺量的影响。水玻璃浓度增大，经水玻璃强化处理的再生骨料表观密度和堆积密度先增大后减小，吸水率逐渐降低，含水率逐渐增加，压碎指标先减小后增大；经水玻璃溶液+纳米碳化硅复合强化的再生骨料随着纳米碳化硅加入量的增加，表观密度和堆积密度先增大后减小，吸水率和含水率均先降低后增大，压碎指标先减小后增大。经浓度为30%的水玻璃溶液+0.75%纳米碳化硅浸泡强化的再生骨料，孔隙和裂缝被改性水玻璃填充，再生骨料表面均匀，综合性能较好，拌制的再生混凝土28 d抗压强度较未处理的再生骨料拌制的混凝土提高约45%，较天然骨料拌制的混凝土低约10%。 Abstract: In order to intensify the recycled aggregate and improve the properties of recycled concrete further, the strengthening effect and mechanism of sodium silicate modified by nano-SiC on the recycled aggregate concrete were studied. The results show that the strengthening effect is obvious ，but it is influenced by concentration of sodium silicate and addition of nano-SiC. As the concentration of water glass is increased, the apparent density and bulk density of the recycled aggregate treated with water glass are firstly increased, the water absorption is gradually reduced, the water content is gradually increased, and the crushing index is increased firstly. With the increase of nano-SiC content, the apparent density and bulk density of recycled aggregate reinforced by nano-SiC solution increased firstly and then decreased, the water absorption and water content decreased first and then increased, and the crushing index decreased first and then increased. The properties of the recycled aggregate which intensified by modified sodium silicate solution with a concentration of 30% and addition of 0.75% nano-SiC are relatively good. The surface of recycled aggregate is even. Pores and cracks are filled with modified sodium silicate. The 28 d compressive strength of corresponding recycled concrete is about 45% higher than the recycled concrete when the recycled aggregate without any treatment, but it is about 10% lower than that of natural aggregate.

徐开东,王继娜,李志新,等.纳米碳化硅改性水玻璃对再生骨料的强化作用机制研究[J].混凝土与水泥制品,2019(7):91-95. XU K D,WANG J N,LI Z X,et al.Research on Reinforcement Mechanism of Sodium Silicate Modified by Nano-SiC on Recycled Aggregate[J].China Concrete and Cement Products,2019(7):91-95.

摘 要：为了研究再生无砂混凝土抗压强度与粒径大小、水灰比和目标孔隙率的关系，采用废弃混凝土破碎作为再生骨料制作成试验样品，在室内进行抗压强度试验。同时为了研究无砂混凝土抗压强度与粒径大小之间的非线性关系，采用三次多项式的方法进行拟合。结果表明：目标空隙率对试件抗压强度具有非线性关系的重要影响；随着粒径尺寸的增大，试件抗压强度先变大再变小；水灰比对试件抗压强度也会产生一定影响。对试验数据的三次多项式拟合比较分析中，当水灰比为0.4时，三种目标孔隙率下的拟合度最好。 Absrtact: In order to study the relationship between the compressive strength of recycled non-fine concrete and particle size, water-cement ratio and target porosity, test samples are made from a municipal building concrete waste yard, and the compressive strength test was carried out in laboratory. In addition, to study the non-linear relationship between the compressive strength and particle size of building non-fine concrete, the cubic polynomial method is used to fit. The results show that the target porosity has an important non-linear effect on the compressive strength of specimens. With the increase of particle size, the compressive strength of specimens first increases and then decreases. Water cement ratio also has a certain impact on the compressive strength of specimens. In the comparative analysis of cubic polynomial fitting of experimental data, when the water cement ratio is 0.4, the fitting degree under three different goal porosities is the best.

孙光林,王爱勤,边亚东,等.再生无砂混凝土抗压强度研究[J].混凝土与水泥制品,2019(7):88-90. SUN G L,WANG A Q,BIAN Y D,et al.Study on Compression Strength of Recycled Non-fine Concrete[J].China Concrete and Cement Products,2019(7):88-90.

摘 要：建立了基于“水化-温度-湿度-约束”多场耦合机制的超高索塔高强大体积强约束混凝土结构收缩开裂风险评估模型，定量分析了开裂风险影响因素；采用温度场与膨胀历程双重调控关键技术制备了绝热温升＜50 ℃、28 d自生体积变形≥50 με的抗裂混凝土；提出了针对性的高强大体积混凝土裂缝控制施工方法。最终形成的集设计、材料、施工、监测于一体的成套技术可控制超高索塔高强大体积混凝土开裂风险＜0.7。 Abstract: Based on the multi-field coupling mechanism of "hydration - temperature - humidity - constraint", the risk assessment model of shrinkage and cracking for large-capacity super-high cable towers with high strong volume and strong constraint concrete structure was established, and the influencing factors of cracking risk were analyzed quantitatively. Adopting the key technology of dual control of temperature field and expansion process，anti-cracking concrete with adiabatic temperature rise <50 °C and 28 d autogenous volume deformation ≥50 με was prepared. A targeted construction method for high strength concrete crack control was proposed. The resulting complete set of technical solutions integrating design, materials, construction and monitoring can control the cracking risk of large-capacity super-high main tower high strength bulk concrete <0.7.

徐文,张士山,李军堂.超高索塔结构混凝土裂缝控制关键技术研究[J].混凝土与水泥制品,2019(7):84-87. XU W,ZHANG S S,LI J T.Research on Key Technology for Crack Control of Super High Cable Tower Structure Concrete[J].China Concrete and Cement Products,2019(7):84-87.

摘 要：立式径向挤压制管工艺由于具有成型时间短生产效率高、自动化程度高、生产成本低、环保节能等优点广泛应用于中小口径钢筋混凝土排水管的生产。本文阐述了立式径向挤压制管的成型机理，对比分析了国内外常用挤压头在机械结构、制管效果、安装调整等方面的差异，同时，介绍了挤压头在生产和维护中的注意事项。 Abstract: The vertical radial extrusion pipe producing process is widely used in the production of small and medium-diameter reinforced concrete drainage pipe due to its advantages such as short molding time, high production efficiency, high automation, low production cost, environmental protection and energy saving. The shaping mechanism of vertical radial extrusion pipe is describled, the mechanical structure, production effect and installation adjustment of common extrusion heads at home and abroad are analyzed and compared, and the precautions of the extrusion head in production and maintenance are introduced.

陈维星.立式径向挤压制管成型及挤压头研究[J].混凝土与水泥制品,2019(7):80-83. CHEN W X.Study on Vertical Radial Extrusion Shaping and Extrusion Head[J].China Concrete and Cement Products,2019(7):80-83.

摘 要：采用文献研究结合专家访谈调研，探讨了装配式混凝土建筑预制凸窗质量安全风险影响因素；基于风险分析理论，采用层次分析法对识别出的风险影响因素进行数据挖掘，计算得出风险影响因素，为判定装配式混凝土建筑预制凸窗风险等级提供决策支撑。 Abstract: Combined literature review and Delphi survey, the risk factors of precast concrete bay window were concluded. Based on risk analysis theory, the analytic hierarchy process was used to processing the indentified factors. The risk-affected factors were calculated. The risk factor levels will contribute to the risk level classification of precast concrete bay window.

戚仁广,邹军,许昂,等.装配式混凝土建筑预制凸窗风险影响因素研究[J].混凝土与水泥制品,2019(7):75-79. QI R G,ZOU J,XU A,et al.The Effecting Risk Factor Research on Precast Concrete Bay Window[J].China Concrete and Cement Products,2019(7):75-79.