共查询到20条相似文献,搜索用时 328 毫秒
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根据已有文献的试验数据建立了混凝土孔隙结构分析的数学模型。基于孔隙结构的研究结果,提出了在冻融循环下混凝土中形成冰晶核的温度和混凝土冻结特征温度的预测方法。预测值与现有的试验观察数据有很好的一致特性。该预测方法可以可靠地用于评估混凝土的状态,判别其处于安全状态还是亚安全状态。 相似文献
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介绍了透明混凝土这一新型建筑材料。讨论了透明混凝土的应用现状、组成成分、各项结构性能和功能特性,并对透明混凝土的组成成分以及施工方法提出一些建议。 相似文献
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本文对FRP加固混凝土梁界面特性研究的众多问题,以及FRP加固混凝土梁FRP-混凝土界面特性研究的局限性进行了总结,分析了FRP-混凝土界面剥离承载力的影响因素、剥离承载力与试验方法的关系问题,归纳和评价了FRP-混凝土界面特性研究的试验方法、剥离承载力与试验方法等关系问题,并提出了FRP-混凝土界面特性研究的宽缺口梁试验法。 相似文献
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简述了火灾的危害,分析了火灾对钢筋混凝土材料性能的影响,探讨了火灾后钢筋混凝土构件承载力的检测与评估,提出了火灾后钢筋混凝土结构的加固原则和加固方法,从而为火灾后工程加固设计提供参考。 相似文献
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Huanjun Jiang Bo Fu Laoer Liu Xiaowei Yin 《The Structural Design of Tall and Special Buildings》2014,23(5):334-349
Many steel–concrete hybrid buildings have been built in China. The seismic performance of such hybrid system is much more complicated than that of steel structure or reinforced concrete (RC) structure. A steel–concrete hybrid frame‐tube super‐tall building structure with new type of shear walls to be built in a district of seismic intensity 8 in China was studied for its structural complexity and irregularity. Both model test and numerical simulation were applied to obtain the detailed knowledge of seismic performance for this structure. First, a 1/30 scaled model structure was tested on the shaking table under different levels of earthquakes. The failure process and mechanism of the model structure are presented here. Nonlinear time‐history analysis of the prototype structure was then conducted by using the software PERFORM‐3D. The dynamic characteristics, inter‐story drift ratios and energy dissipation conditions are introduced. On the basis of the comparison between the deformation demand and capacity of main structural components at individual performance level under different earthquake level, the seismic performance at the member level was also evaluated. Despite the structural complexity and code‐exceeding height, both experimental and analytical results indicate that the overall seismic performance of the structure meet the requirements of the Chinese design code. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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Demolished concretes to be recycled show great diversity in property with regard to residual potential of resistance to the environmental effects such as frost action, when they are used in a new concrete as aggregate. There seems to exist no appropriate test method fitting specific characteristics of the recycled concrete aggregates with respect to the fair judgement of their unbound state frost durability. This fact rises another important prejudice against performance of recycled concrete aggregates compared to virgin alternatives. This study deals with reliable identification of frost susceptibility of recycled concrete aggregates. An unbound frost durability test with a mild pre-drying procedure (at 50 °C) was performed on recycled concrete aggregates originated from both air-entrained and non-air-entrained type of source concretes. The procedure distinctly identified the non-durable recycled coarse aggregates in parallel to freezing and thawing durability results of the concretes incorporating identical aggregates. Sulfate soundness test gave misleading results in judgement of the unbound state frost durability due to the highly disruptive physicochemical effect of the method on the recycled concrete aggregates, regardless of the air void characteristics of the materials. 相似文献
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为探究火灾后采用聚合物砂浆加固修复混凝土空心楼盖二次火灾下的抗火性能,对四边简支混凝土组合塑料模盒空心楼盖进行两次火灾试验。介绍了试验空心楼盖第一次受火试验及火灾后构件修复情况,重点介绍了加固修复后空心楼盖第二次火灾试验,描述了试验空心楼盖在两次受火下的破坏特征、变形和温度场分布规律,并进行分析和对比。研究结果表明:采用聚合物砂浆修复的空心楼盖在二次火灾作用下,第一次火灾受损较为严重的部位易产生爆裂脱落,从而降低了耐火极限;二次受火下楼盖内混凝土的温度峰值高于一次受火,且距离板底越近,两次火灾作用中温度峰值差值越大;试件在两次火灾作用下跨中处最大竖向位移基本相同,第二次受火作用后的残余位移小于第一次;采用聚合物砂浆对火灾后的空心楼盖进行修复,修复后的楼盖仍具有一定的抗火性能。 相似文献
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Experimental and analytical studies on the seismic performance of high strength concrete beams in moment resisting frame structures are described. Two large-scale high strength concrete and two counterpart normal strength concrete model beams with a length-to-depth ratio of 6·0 (i.e. shear span ratio of 3·0) have been tested under cyclic shear and double bending. The beams were heavily reinforced in the longitudinal direction to study beam performance under high seismic shear demand. Transverse reinforcement was designed following the seismic design provisions of current ACI 318–95 code. Both high and normal strength concrete beams developed ductile flexural responses. High strength concrete beams exhibited increased capacity and improved hysteretic performance compared to normal strength concrete beams. A simple analytical approach based on the moment curvature characteristics of critical sections has also been developed to predict the flexural behavior of structural beams. Comparison of analytical and test results indicates that behavior of high strength concrete beams can be satisfactorily predicted. © 1998 John Wiley & Sons, Ltd. 相似文献
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介绍了高性能混凝土的特点,从其原材料、制备及工程应用情况等方面进行了阐述,并提出了智能混凝土、自修复混凝土、爆压成型混凝土等目前混凝土领域较新的研究动向。 相似文献
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从钢筋混凝土的钢筋锈蚀理论出发,结合混凝土材料科学,概述了微胶囊的制备方法与触发机理,列举了不同触发型微胶囊阻锈剂的触发方式及触发过程;介绍了适用于研究微胶囊基本性能与表征的测试体系;总结了国内外关于微胶囊阻锈剂对混凝土性能影响的试验成果,指出了研究现状中的一些不足,并在此基础上提出有待深入研究的问题。 相似文献