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Application of Geological Prospecting Radar to Detecting the Reinforced Concrete Blocks of East Runway of the Capital International Airport of China
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作者 宁书年 杨峰 席拥军 《International Journal of Mining Science and Technology》 SCIE EI 1997年第1期25-28,共4页
The geological prospecting radar, a high-techuology rapidly developed in recent years, is used in the field of nondestructive testing and object detecting, in accordance with the reflection principle of high-frequency... The geological prospecting radar, a high-techuology rapidly developed in recent years, is used in the field of nondestructive testing and object detecting, in accordance with the reflection principle of high-frequency electromagnetic wave. It will be effective if there exists a large difference in the electromagnetic properties between an object body and its surroundings. The result of using the geological prospecting radar in detecting the concrete blocks with ber in the capital internatioual airport’s east runway is aualyed in detail herein. The introduction of the geological prospecting radar provides a new approach to nondotodive testing. 展开更多
关键词 GEOLOGICAL PROSPECTING RADAR concrete blocks with reinforcing bar NONDESTRUCTIVE testing
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Quality Assessment of Concrete Blocks Exposed in Nature for Eighty Years
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作者 Hu Yuchu , Wu Shaozhang Lu Liyun Senior Engineer, Nanjing Hydraulic Research Institute, 210029 Nanjing Professor and Senior Engineer, Nanjing Hydraulic Research Institute, 210029 Nanjing Assistant Engineer, Nanjing Hydraulic Research Institute, 210029 Nanjing 《China Ocean Engineering》 SCIE EI 1992年第4期455-470,共16页
The concrete blocks used on a jetty in Shanghai were made in 1909 and 1910. Having been exposed in nature for 80 years, now there are 4600 pieces of blocks left on the jetty. Comprehensive inspections, such as externa... The concrete blocks used on a jetty in Shanghai were made in 1909 and 1910. Having been exposed in nature for 80 years, now there are 4600 pieces of blocks left on the jetty. Comprehensive inspections, such as external appearance examination, core-drilling of concrete blocks, ultrasonic detection, nuclear densimeter inspection and in-door and out-door chemical analysis, show that 75% of the blocks are of the rebound number of 21 - 23, and the saturated limit compressive strength and dry limit compressive strength of 10MPa; the carbonized depth of concrete is 1 - 2 mm. Compared with the state of the jetty in 1968, already used for 60 years then, the jetty is expected to serve another 40 years or more after being repaired. 展开更多
关键词 jetty concrete block damage inspection DURABILITY
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Analysis of Waste in the Production of Concrete Blocks---A Case Study in the Goias Industry
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作者 Tatiana Gondim do Amaral Weslley M. Cruz Jose R. Perim 《Journal of Civil Engineering and Architecture》 2015年第8期926-937,共12页
An ever more demanding consumer market and the need for companies to be more competitive have led organizations to try to eliminate waste. This research is a case study which presents a proposal for intervention in or... An ever more demanding consumer market and the need for companies to be more competitive have led organizations to try to eliminate waste. This research is a case study which presents a proposal for intervention in order to improve performance of a pre-cast concrete block factory in outer Goihnia. As a first step, waste in the production process was identified through analysis of data on time involved in each step of the process. Then, applying the concepts of lean production, a list of activities was drawn up with a view to eliminating non-value-added work, identifying waste, decreasing cycle time, streamlining the production process and increasing the flexibility and transparency of the process. From the results, it was possible to identify the sources of waste and provide management with information for strategic decisions about production. Finally, various suggestions were made with a view to eliminating or mitigating bottlenecks in the production process. 展开更多
关键词 Lean production WASTE concrete blocks continuous improvement.
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Experimental Performance Measures of Recycled Insulation Concrete Blocks from Construction and Demolition Waste
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作者 Doudou Liu Liang Qiao Guozhong Li 《Journal of Renewable Materials》 SCIE EI 2022年第6期1675-1691,共17页
Construction and demolition(C&D)waste has seriously affected the ecological environment.The utilization of C&D waste resources can greatly alleviate this problem,and it is an important way to help achieve the ... Construction and demolition(C&D)waste has seriously affected the ecological environment.The utilization of C&D waste resources can greatly alleviate this problem,and it is an important way to help achieve the goal of zero carbon in 2050.In this study,insulation concrete blocks were developed with recycled aggregates,cement,fly ash as main raw materials,expanded polystyrene(EPS)insulation boards as block insulation filling material,and selfdeveloped construction waste composite activator,interface enhancer,surface modifier and other additives.Through experimental research and performance test analysis,the best mix ratio of the product and the mechanism of each additive were proved.The experimental results showed that the insulation concrete block prepared under the conditions of recycled aggregates sand ratio of 45%,active activator Na_(2)SO_(4)content of 0.15%and fly ash content of 30%has the best performance and meets the relevant standards. 展开更多
关键词 C&D waste recycled insulation concrete blocks experimental performance
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Mechanical Behavior of Concrete Block Masonry
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作者 Gihad Mohamad Eduardo Rizzatti +1 位作者 Paulo Brandao Lourenco Humberto Ramos Roman 《Journal of Civil Engineering and Architecture》 2012年第10期1354-1361,共8页
The main objective of this study is to verify, through compression tests on different prisms, the vertical and horizontal deformability and the failure modes of the components of concrete blocks under compression. In ... The main objective of this study is to verify, through compression tests on different prisms, the vertical and horizontal deformability and the failure modes of the components of concrete blocks under compression. In this study two mortar mixes were tested, along with two types of prism, with and without the presence of a vertical joint. The conclusions were: the appearance of non-linearities of the masonry corresponds to an increase in the lateral strain due to extensive cracking of the material and a progressive increase in the Poisson ratio, the cracks in the three-block prisms built with the mortar type I were vertical, occurring symmetrically on both sides; the prisms built with mortar type II had, as a consequence of localized crushing, an association with vertical cracks due to the concentrations of stresses at some points, the presence of a vertical joint led to the appearance of separation cracks between the middle block and the vertical mortar joint, when the stress reached approximately 30% of the compressive strength of the set; the prisms with two whole blocks and one vertical joint (B) built with the mortars of mixes I and II had a compressive strength of the order of 42% and 66% of the prisms with three whole blocks (A), respectively. 展开更多
关键词 MASONRY concrete block PRISMS FAILURE vertical joint
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Research on Concrete Beam Crack Recognition Algorithm Based on Block Threshold Value Image Processing
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作者 Wenting Qiao Xiaoguang Wu +1 位作者 Wen Sun Qiande Wu 《Structural Durability & Health Monitoring》 EI 2020年第4期355-374,共20页
To solve the problem that the digital image recognition accuracy of concrete structure cracks is not high under the condition of uneven ill umination and complex surface color of concrete structure,this paper has prop... To solve the problem that the digital image recognition accuracy of concrete structure cracks is not high under the condition of uneven ill umination and complex surface color of concrete structure,this paper has proposed a block segmentation method of maximum entropy threshold based on the digital image data obtained by the ACTIS automatic detection system.The steps in this research are as follows:1.The crack digital images of concrete specimens with typical fea-tures were collected by using the Actis system of KURABO Co,Ltd,of Japan in the concrete beam bending test.2.The images are segmented into blocks to dis-tinguish backgrounds of different grayscale.3.The max imum interclass average gray difference method is used to distinguish the sub-blocks and screen out the image blocks that need to be segmented.4.Segmentation is made to the image with 2D max imum entropy threshold segmentation method to obtain the binary image,and the target image can be obtained by screening the connected domain features of the binary image.Results have shown that compared with other algo-rithms,the proposed method can effectively decrease the image over-segmentation and under segmentation rates,highlight the characteristics of the target cracks,solve the problems of excessive difference between the identified length and actual length of cracks caused by background gray level change and uneven ilumnination,and effectively improve the recognition accuracy of bridge concrete cracks. 展开更多
关键词 concrete crack block segmentation maximum entropy segmentation algorithms maximum interclass variance(Otsu)method
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公路轻型砌块式挡土墙受力特性及设计计算方法研究 被引量:6
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作者 赵明华 罗宏 邹新军 《中南公路工程》 2005年第1期5-9,12,共6页
提出一种运用于公路的轻型砌块挡土墙 ,对其结构体系及组成进行了概述。利用Marc有限元程序对局部砌块单元以及整体结构的变形及受力进行了受力分析 ,对该挡土结构的整体设计计算及稳定性分析方法进行了探讨。分析结果与工程实用经验表... 提出一种运用于公路的轻型砌块挡土墙 ,对其结构体系及组成进行了概述。利用Marc有限元程序对局部砌块单元以及整体结构的变形及受力进行了受力分析 ,对该挡土结构的整体设计计算及稳定性分析方法进行了探讨。分析结果与工程实用经验表明 ,H形砌块挡土结构能充分利用材料的抗压性能 ,施工速度快、排水性能良好。 展开更多
关键词 Marc
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Autoclaved Aerated Concrete Block Prefabricated Multi-Storey Building Technology
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作者 Jingjing Sun 《Journal of World Architecture》 2022年第2期1-4,共4页
In active response to the national requirements of promoting green building materials and developing prefabricated buildings,it is necessary to continuously optimize and reasonably employ relevant technologies.Autocla... In active response to the national requirements of promoting green building materials and developing prefabricated buildings,it is necessary to continuously optimize and reasonably employ relevant technologies.Autoclaved aerated concrete block prefabricated multi-storey building technology is a new technology,which will not only effectively realize green environmental protection in construction engineering,but also promote the further development of prefabricated buildings.Therefore,this paper analyzes the autoclaved aerated concrete block prefabricated multi-storey building technology for future references. 展开更多
关键词 Autoclaved aerated concrete Building block Prefabricated building Multi-storey building
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Experimental study on the compressive strength of grouted concrete block masonry based on nondestructive detection methods 被引量:1
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作者 姜洪斌 李龙飞 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2009年第2期189-193,共5页
Existing nondestructive detection methods were adopted to test the compressive strength of grouted concrete block masonry,i.e.the rebound method,pulling-out method and core drilling method were employed to test the st... Existing nondestructive detection methods were adopted to test the compressive strength of grouted concrete block masonry,i.e.the rebound method,pulling-out method and core drilling method were employed to test the strength of block,mortar and grouted concrete,respectively.The suitability of these methods for the testing of strength of grouted concrete block masonry was discussed,and the comprehensive strength of block masonry was appraised by combining existing nondestructive or micro-destructive detection methods.The nondestructive detection test on 25 grouted concrete block masonry specimens was carried out.Experimental results show that these methods mentioned above are applicable for the strength detection of grouted concrete block masonry.Moreover,the formulas of compressive strength,detection methods and proposals are given as well. 展开更多
关键词 grouted concrete block masonry compressive strength nondestructive detection
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马鞍山长江公铁大桥主航道桥中塔下横梁施工关键技术
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作者 刘爱林 徐敏 王伟 《世界桥梁》 北大核心 2024年第4期29-34,共6页
马鞍山长江公铁大桥主航道桥Z4号中塔采用空间四肢A形钢-混组合塔,横向两塔肢间设下横梁,下横梁间设3道系梁,纵向两塔肢间不设置横梁。下横梁采用支架法分层浇筑施工。下横梁施工支架采用落地式钢管支架配套模板体系,受力性能满足要求;... 马鞍山长江公铁大桥主航道桥Z4号中塔采用空间四肢A形钢-混组合塔,横向两塔肢间设下横梁,下横梁间设3道系梁,纵向两塔肢间不设置横梁。下横梁采用支架法分层浇筑施工。下横梁施工支架采用落地式钢管支架配套模板体系,受力性能满足要求;通过有限元计算比选下横梁混凝土分层浇筑方案并进行优化,采取(5.5+2.5)m分层方案,上、下层混凝土分别分为2块、3块分层分块浇筑;通过低温升、易泵送、高抗裂的C60混凝土研制、下横梁与塔柱倒弧结合面抗裂措施优化、分块间接缝构造形式及施工工艺优化、下横梁与系梁混凝土浇筑施工组织优化、混凝土温度智能化监控、预应力束张拉时机控制等混凝土防裂措施,有效解决了下横梁大体积混凝土易开裂的难题。 展开更多
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混凝土小型空心砌块墙片伪静力试验研究 被引量:2
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作者 周抚生 郭迅 +1 位作者 郑志华 毛国成 《世界地震工程》 CSCD 北大核心 2005年第2期75-79,共5页
由于强度、环保、施工方便等多方面的优势,混凝土空心砌块成为粘土砖的最理想的替代材料。不过砌块建筑经历的震害很少,抗震研究的成果也少。针对多层砌块建筑的抗震设计需求,模拟不同楼层压力,对15片1.4m×1.2m的空心混凝土砌块墙... 由于强度、环保、施工方便等多方面的优势,混凝土空心砌块成为粘土砖的最理想的替代材料。不过砌块建筑经历的震害很少,抗震研究的成果也少。针对多层砌块建筑的抗震设计需求,模拟不同楼层压力,对15片1.4m×1.2m的空心混凝土砌块墙片进行了伪静力试验,得到了往复力-位移曲线,可供砌块结构抗震设计参考。 展开更多
关键词 线
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钢管混凝土双块式轨枕无砟轨道结构疲劳性能试验研究 被引量:1
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作者 刘晓春 陈佳琦 +3 位作者 罗延亮 朱志辉 李启航 郑纬奇 《铁道科学与工程学报》 EI CAS CSCD 北大核心 2024年第1期106-115,共10页
新型钢管混凝土(CFT)双块式轨枕克服了桁架钢筋双块式轨枕存在的生产制造复杂、存放易锈蚀、运营阶段易开裂等问题,可广泛应用于高速铁路和城市轨道交通无砟轨道结构。为检验CFT双块式轨枕无砟轨道结构的疲劳性能,采用11根预制CFT双块... 新型钢管混凝土(CFT)双块式轨枕克服了桁架钢筋双块式轨枕存在的生产制造复杂、存放易锈蚀、运营阶段易开裂等问题,可广泛应用于高速铁路和城市轨道交通无砟轨道结构。为检验CFT双块式轨枕无砟轨道结构的疲劳性能,采用11根预制CFT双块式轨枕现浇制作足尺无砟轨道结构节段模型,开展橡胶隔振垫式减振轨道和现浇整体式轨道节段的疲劳试验,揭示其疲劳损伤特性,分析典型疲劳加载循环次数后静载作用下轨道结构应变和变形分布及其演化规律。研究结果表明:1.5倍静轴重的疲劳荷载累计作用500万次后,减振节段及整浇节段CFT双块式轨枕无砟轨道结构混凝土均未出现肉眼可见的裂缝,轨枕与现浇道床整体工作性能良好,疲劳性能满足规范要求;停机开展静载试验过程中轨道结构各测点混凝土横向应变值随荷载增大而近似线性增大,最大拉压应变值均远小于混凝土的极限应变值,工作状态良好;轨道整浇节段道床板中处于整体受拉的状态,可见设置层间连接钢筋实现了道床与底座的共同工作;疲劳试验过程中轨道结构测点竖向位移值总体随着静载的增大而逐渐增大,位移量级较小,满足规范要求,减振轨道节段竖向位移值及其变化率大于整浇轨道节段。研究结果可供类似研究及钢管混凝土双块式轨枕无砟轨道结构工程应用参考。 展开更多
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Thermal Analysis of Concrete Mixtures with Recycled EPS Aggregates
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作者 Aisha Ayoubi Emilio Sassine +3 位作者 Joseph Dgheim Joelle Al Fakhoury Yassine Cherif Emmanuel Antczak 《Journal of Building Material Science》 2022年第2期36-45,共10页
Reusing recycled waste materials in buildings is gaining more and more attention for what it offers economic,environmental,and energy benefits;and many researchers are nowadays working on producing new sustainable con... Reusing recycled waste materials in buildings is gaining more and more attention for what it offers economic,environmental,and energy benefits;and many researchers are nowadays working on producing new sustainable construction materials incorporating recycled wastes.In this scope,this work uses an experimental approach aiming at understanding the effect of incorporating Expanded Polystyrene(EPS)beads in concrete and proposing thermally improved concrete mixtures for the production of hollow blocks in Lebanese constructions by substituting fine aggregates with recycled products such as EPS in order to promote their insulating properties.Three different diameters of EPS beads(2 mm~3 mm,3 mm~4 mm and 4 mm~5 mm)are studied with different volumetric ratios(20%,40%,60%and 80%)in order to investigate the effect of EPS on the thermal properties of concrete.The results showed that the only the percentage of incorporated EPS beads impacted the thermal performance of the concrete mixtures while the EPS diameters have a negligible effect on the thermal properties of the concrete samples. 展开更多
关键词 concrete mixtures Hollow blocks EPS beads Thermal properties Thermal insulation Recycled wastes
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压缩浇筑混凝土的应力-应变关系
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作者 吴宇飞 汪勋 +1 位作者 袁方 胡彪 《深圳大学学报(理工版)》 CSCD 北大核心 2024年第1期42-49,共8页
压缩浇筑可以显著提高混凝土的强度和耐久性,无需添加任何化学添加剂和矿物掺料.采用压缩浇筑方法制作压缩浇筑混凝土试件,并开展单轴受压试验.试验结果表明,相比于普通混凝土,压缩浇筑混凝土的抗压强度和弹性模量显著提高,而峰值应力... 压缩浇筑可以显著提高混凝土的强度和耐久性,无需添加任何化学添加剂和矿物掺料.采用压缩浇筑方法制作压缩浇筑混凝土试件,并开展单轴受压试验.试验结果表明,相比于普通混凝土,压缩浇筑混凝土的抗压强度和弹性模量显著提高,而峰值应力对应的应变稍有减小.基于现有混凝土应力-应变模型对试验结果进行回归分析,得到压缩浇筑混凝土的应力-应变关系模型.在此基础上,利用受弯定理推导了压缩浇筑混凝土受弯构件的等效矩形应力块参数模型.研究成果可为压缩浇筑混凝土构件的抗弯设计和分析提供理论依据. 展开更多
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Coupled Conductive-Convective-Radiative Heat Transfer in Hollow Blocks with Two Air Cells in the Vertical Direction Subjected to an Incident Solar Flux
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作者 Mourad Najjaoui Thami Ait-taleb +2 位作者 Abdelhalim Abdelbaki Zaki Zrikem Hassan Chaib 《Fluid Dynamics & Materials Processing》 EI 2022年第5期1399-1407,共9页
This work presents the results of a set of steady-state numerical simulations about heat transfer in hollow blocks in the presence of coupled natural convection,conduction and radiation.Blocks with two air cells deep ... This work presents the results of a set of steady-state numerical simulations about heat transfer in hollow blocks in the presence of coupled natural convection,conduction and radiation.Blocks with two air cells deep in the vertical direction and three identical cavities in the horizontal direction are considered(typically used for building ceilings).Moreover,their outside horizontal surface is subjected to an incident solar flux and outdoor environment temperature while the inside surface is exposed to typical indoor environment conditions.The flows are considered laminar and two-dimensional over the whole range of parameters examined.The conservation equations are solved by means of a finite difference method based on the control volumes approach,relying on the SIMPLE algorithm for what concerns the coupling of pressure and velocity.The effects of the number of cells in the horizontal direction and the thermal conductivity on the heat transfer through the alveolar structure have been investigated.The results show that the number of holes has a significant impact on the value of the overall heat flux through the considered structure. 展开更多
关键词 Numerical simulation heat transfer coupled hollow concrete block control volumes approach
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废水泥浆对陶粒加气混凝土砌块性能的影响研究
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作者 王艳红 庄建钢 +3 位作者 吴育萍 朱锋盼 沈伟锋 姚永鹤 《新型建筑材料》 2024年第2期103-106,111,共5页
在废水泥浆中的水取代全部拌合水的条件下,探究废水泥浆中的粉体以等量取代或系数为0.65~1.05折算取代部分粉煤灰时,对陶粒加气混凝土和易性及陶粒加气混凝土砌块抗压强度、干密度、干燥收缩、导热系数的影响。研究表明,水胶比为0.45,... 在废水泥浆中的水取代全部拌合水的条件下,探究废水泥浆中的粉体以等量取代或系数为0.65~1.05折算取代部分粉煤灰时,对陶粒加气混凝土和易性及陶粒加气混凝土砌块抗压强度、干密度、干燥收缩、导热系数的影响。研究表明,水胶比为0.45,当废水泥浆浓度为0~18%时,按等量取代后,砌块28 d平均抗压强度为5.51~5.54 MPa,干密度为728~730 kg/m~3,干燥收缩值为0.28~0.41 mm/m,导热系数为0.137~0.145 W/(m·K);当废水泥浆浓度为20%时,按系数为0.75~0.95折算取代后,砌块28 d平均抗压强度为5.18~5.43MPa,干密度为732~743 kg/m~3,干燥收缩值为0.35~0.42 mm/m,导热系数为0.146~0.178 W/(m·K),此时,砌块符合JG/T 504—2016对CA5.0B07砌块要求。 展开更多
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Studying the Properties of Lightweight Concrete Using Construction Materials Waste
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作者 Aamer Najim Abbas Hussain Haider Abdulzahra 《Journal of Environmental Science and Engineering(A)》 2015年第6期295-302,共8页
The main purpose of this research is to study the mechanical properties of lightweight concrete through the using of different types of lightweight aggregate. Three types of lightweight aggregate were used in this stu... The main purpose of this research is to study the mechanical properties of lightweight concrete through the using of different types of lightweight aggregate. Three types of lightweight aggregate were used in this study for the production of lightweight concrete. These types are red block aggregate, red ceramic aggregate and white thermostone aggregate. All these types have been brought from construction waste. A comparison of the properties of lightweight concrete with normal concrete is the most important goal of this study. The most important properties of concrete, which were compared with each other is compressive strength, static modulus of elasticity, splitting tensile strength and slump flow. 展开更多
关键词 Lightweight concrete red block aggregate red ceramic aggregate white thermostone aggregate.
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钢管混凝土双块式轨枕道床复合受力性能试验
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作者 刘晓春 姚军 +3 位作者 罗延亮 李启航 朱志辉 余志武 《铁道科学与工程学报》 EI CAS CSCD 北大核心 2024年第10期4040-4052,共13页
新型钢管混凝土(CFT)双块式轨枕采用钢管混凝土取代了桁架钢筋的连接构件作用,具有结构简单、安全耐久性好等优点。为研究钢管混凝土双块式轨枕与现浇混凝土道床所形成的轨道结构的复合受力性能,采用某实际工程的材料和工艺制作了一段足... 新型钢管混凝土(CFT)双块式轨枕采用钢管混凝土取代了桁架钢筋的连接构件作用,具有结构简单、安全耐久性好等优点。为研究钢管混凝土双块式轨枕与现浇混凝土道床所形成的轨道结构的复合受力性能,采用某实际工程的材料和工艺制作了一段足尺CFT轨枕减振道床和现浇整体道床,经疲劳试验验证后,用绳锯将其沿横向切割成单承轨台和双承轨台的CFT轨枕道床试件,分别开展试件的轨下截面加载试验和中间截面加载试验,分析道床试件中轨枕、现浇道床、底座板混凝土和钢筋的应力、变形及裂缝的开展演化规律。试验结果表明:CFT轨枕道床受力破坏过程均表现出整体工作、带裂缝工作和破坏的典型三阶段特征;中间截面加载试件破坏时受拉钢筋被拉断而受压区混凝土未被压碎,类似于低筋破坏,轨下截面加载试件因竖向裂缝和弯剪区段斜裂缝之间的混凝土被压碎剥落而失效,受拉纵筋未屈服,类似于斜压破坏;CFT轨枕整体道床试件抗裂能力、承载能力更高,整体道床试件开裂荷载约为减振道床试件相应值的4.7倍,其极限荷载约为减振道床的2.3倍,道床与底座板之间采用拉结钢筋连接后能大幅提升轨道结构刚度和承载能力。CFT轨枕与现浇道床界面黏结及整体工作性能良好,研究成果可供钢管混凝土双块式无砟轨道理论研究和工程应用参考。 展开更多
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大掺量粉煤灰蒸压加气混凝土的制备试验研究--以双氧水为发气剂
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作者 王正 胡荣建 +4 位作者 杨朝刚 刘会军 赵天祥 张美霞 张慧月 《中国资源综合利用》 2024年第8期6-9,22,共5页
粉煤灰是煤炭燃烧后产生的固体废弃物,若采用填埋处理,则会对环境造成很大危害。试验以粉煤灰为主要基体材料,将双氧水作为发气剂,从影响双氧水的发气条件入手,复掺生石灰和水泥作为胶凝材料,添加石膏作为缓凝剂,另加少量激发剂和稳泡剂... 粉煤灰是煤炭燃烧后产生的固体废弃物,若采用填埋处理,则会对环境造成很大危害。试验以粉煤灰为主要基体材料,将双氧水作为发气剂,从影响双氧水的发气条件入手,复掺生石灰和水泥作为胶凝材料,添加石膏作为缓凝剂,另加少量激发剂和稳泡剂,制备蒸压加气混凝土砌块,从而有效实现粉煤灰大掺量利用。检测结果显示,在最佳的反应时间、双氧水浓度、催化剂添加量、溶液pH、水浴温度和双氧水添加量等发气条件下,蒸压加气混凝土砌块的抗压强度为5.2MPa,干密度为579kg/m^(3),符合强度等级A5.0、密度等级B06的产品质量要求。 展开更多
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新型钢管混凝土枕式无砟轨道动力响应试验研究
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作者 朱志辉 李启航 +1 位作者 刘晓春 郑纬奇 《中南大学学报(自然科学版)》 EI CAS CSCD 北大核心 2024年第6期2310-2319,共10页
采用钢管混凝土构件连接轨枕块形成钢管混凝土轨枕,基于钢管混凝土轨枕设计城市轨道交通用钢管混凝土枕式无砟轨道结构。为掌握钢管混凝土枕式无砟轨道结构在城市轨道交通列车运行条件下的力学性能,验证结构设计的安全性、合理性,分别... 采用钢管混凝土构件连接轨枕块形成钢管混凝土轨枕,基于钢管混凝土轨枕设计城市轨道交通用钢管混凝土枕式无砟轨道结构。为掌握钢管混凝土枕式无砟轨道结构在城市轨道交通列车运行条件下的力学性能,验证结构设计的安全性、合理性,分别在减振地段、普通地段铺设钢管混凝土枕式无砟轨道,通过行车试验,测试分析不同列车行驶速度下无砟轨道钢轨、轨枕、道床结构的动力响应。研究结果表明:在列车车速为40、60和80 km/h运行条件下,轮轨垂向力最大值为86.18 kN,横向力最大值为13.99 kN,脱轨系数最大值为0.21,轮重减载率最大值为0.23,测试值均明显小于相应的安全限值,无砟轨道结构满足行车安全性要求;在列车动荷载作用下,钢管混凝土轨枕钢管压应力最大值为3.55 MPa,拉应力最大值为3.77 MPa;轨枕块压应力最大值为1.32 MPa;道床钢筋压应力最大值为2.30 MPa,拉应力最大值为3.54 MPa;道床底压应力最大值0.22 MPa。这些动力响应结果均满足材料的的限值,表明结构保持了良好的力学性能,结构设计合理可行。 展开更多
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