混凝土骨料二维分布的模拟和应用

通过在一个矩形截面上模拟混凝土骨料的实际分布，获得了该截面上任一点的骨料分布密度和骨料分布的统计特性。模拟结果表明，当模拟次数趋向于无穷大时，截面上任一点的骨料分布密度趋向于定值，对于不同的骨料面积百分数，骨料分布密度曲线的形状十分相似，均由上升段和水平段两部分组成。基于这些模拟结果，利用数学拟合获得了骨料分布密度的解析表达式，并被混凝土实验所初步证实。作为一个应用，本文计算了混凝土截面上各点的氯离子扩散系数。     

Repair of Cracked Aluminum Overhead Sign Structures with Glass Fiber Reinforced Polymer Composites

Transportation departments have been using aluminum overhead sign structures since the 1950s. It is well documented that cracks develop in the welds between diagonal and chord members due to fatigue stresses from wind-induced vibration of the slender members. The cracks propagate to complete failure of the members, which can cause collapse of the truss and inflict injuries. The original design of overhead sign structures did not consider fatigue as a limit state. In addition, field welding of aluminum structures for any possible repairs is prohibited. A repair method for the cracked aluminum welded connections between diagonals and chord members using glass fiber reinforced polymer composites (GFRPs) is proposed. The static load carrying capacity of the welded connection, and the cracked connection repaired with GFRP composites are established. The paper describes the surface preparation of the aluminum tubular members, and the architecture and application sequence of the GFRP composite to retrofit the connection. Experimental results are presented from static tests of welded aluminum connections, welded aluminum connections retrofitted with GFRP composites, and new aluminum connections that depend only on GFRP composite elements for their strength. The results from monotonic static tests carried out on cracked welded specimens from actual sign structures show that the retrofitted connection with GFRP reinforcement achieved 1.17 to 1.25 times the capacity of the welded aluminum connection without any visible cracks. This result, and the minimal traffic disruption anticipated in the actual field application, makes this retrofit method a good candidate for implementation.     

螺纹钢牙筋长度不足的原因及解决办法

分析了影响螺纹钢牙筋长度的原因，根据铣床的工作原理，利用刀头夹持长度与凸轮工作轨面半径的几何关系，推导出计算各种不同规格螺纹钢牙筋的工艺参数，解决了螺纹钢牙筋长度不足之问题。     

免振捣自密实混凝土技术在多层住宅中的应用

介绍了免振捣自密实混凝土的特点和质量控制措施，结合某小区自密实混凝土工程应用实例，阐述了该项施工技术，其经济和社会效益良好，提出了进一步发展该技术的若干设想。     

在湿陷性黄土地区对混凝土夯扩桩的检测

对夯扩桩在豫西湿陷性黄土地区的应用和可行性分析与检测。     

Investigation on compounding and application of C80-C100 high-performance concrete

This paper presents the compounding technology and application of C80-C100 high-performance concrete (HPC) containing ultra-pulverized fly ash composite (PFAC) and superplasticizer. The properties of C80-C100 HPC are also studied systematically. The experimental results indicate that this concrete has excellent workability, high strength, lower drying shrinkage, outstanding volume stability, durability, etc.     

Porosity of recycled concrete with substitution of recycled concrete aggregate: An experimental study

In this paper, we present the experimental analysis of samples of recycled concrete (RC) with replacement of natural aggregate (NA) by recycled aggregate originating from concrete (RCA). The results of the tests of mechanical properties of RC were used for comparison with tests of mercury intrusion porosimetry (MIP), in which the distribution of the theoretical pore radius, critical pore ratio, the surface area of the concrete, threshold ratio and average pore radius were studied at ages of 7, 28 and 90 days. The results showed some variation in the properties of the RC with respect to ordinary concrete. Porosity increases considerably when NA is replaced by RCA. Additionally, a reduction in the mechanical properties of the RC is seen compared with ordinary concrete when porosity increases.     

重力坝深(底)孔断面钢筋混凝土模型试验研究

文通过7个小尺寸和1个大尺寸的钢筋混凝土断面模型试验，研究重力坝深(底)孔在坝体自重和内水压力以及超内水压力作用下的结构特性和破坏规律。重点探讨混凝土和钢筋应力应变、混凝土开裂、裂缝宽度和裂缝扩展规律，为建立更为科学的孔口配筋理论提供依据。     

厚壳玻璃钢艇体选材、铺层设计及工艺

本文涉及玻璃钢猎扫雷艇艇体材料的优选、铺层设计和工艺等内容。试验确定了以１６２９间苯聚酯树脂为基体、以９００ｇ／ｍ２无碱无捻粗纱短切毡（Ｍ）和８１０ｇ／ｍ２无碱无捻粗纱方格布（Ｒ）为增强体以及（Ｍ＋Ｒ）为基本铺层设计单元的方案。试验表明，按上述材料和铺层制作的层板，性能达到Ｌｅｒｉｃｉ和ＭＨＣ－５１艇壳层板的指标要求。     

预应力工程中的OVM锚固体系

ＯＶＭ锚固体系是我国第一种采用二片四开式，锚碇１８６０ＭＰａ级低松弛钢绞线的预应力锚固体系。本文介绍其基本性能，与其他系列锚具的组合以及它在斜拉桥主索上的应用。