全部文章
第四期
周孝红,陈国平,朱水文
摘 要:将稻草原材料制成不同粒径的微粒,并分别按不同掺量制成复合砂浆,通过试验得到复合砂浆抗折强度、抗压强度、干缩率以及导热系数变化规律。研究结果表明,稻草纤维微粒能有效改善砂浆物理力学性能,为节能环保起到有效的推动作用。
Abstract: The different size of particle is produced by straw raw material, composite mortar is made of different dosage of particle. The change rules of the flexural strength, compressive strength, dry shrinkage and thermal conductivity variation of composite mortar is obtained by experiment. The results show that, the straw fiber particle can effectively improve the physical and mechanical properties of the mortar,which can promote the energy saving and environmental protection.
蒋跃楠1,万大前2
摘 要:以江宁医改中心一期工程为依托,探讨了桩基础的设计与施工方法,分析了抗拔桩与抗压桩的静载试验。结果表明,本工程的抗拔桩平均回弹率一般大于抗压桩;抗拔桩回弹变形中桩身的弹性恢复只是小部分,桩身质量对抗拔桩的变形有一定影响;同一地段发生同等位移条件下,抗压荷载明显大于抗拔荷载且荷载差异随位移的增加而增加;荷载作用下的基桩变形与检测的间隔时间关系不大。
Abstract: As project of Jiangning hospitalcare center Ⅰ, design and construction method of pile foundation are investigated, static load experimental results of tension pile and compression pile are analyzed. The results show that, average rebound rate of tension pile in this project is more than compression piles; elastic recovery of tension pile in rebound deformation is a small part, there is the influence of pile quality on deformation of tension pile; under the same area and same condition of displacement, compression load is obviously more than tension load, and with increasing the displacement, the load difference is increased; under the role of load,pile deformation and detected interval have little relationship. Key words: Tension pile; Compression pile; Static load experiment; Deformation amout
张宏博1,2,解全一1,2,岳红亚1,2,李 信1,2,马 源1,2
摘 要:为研究对拉式挡土墙失稳时的力学响应规律,设计了室内模型试验,监测并分析了对拉式挡土墙在倾覆破坏和沉降破坏时墙背侧向土压力分布特征及拉筋应力的变化规律。研究结果表明,在对拉式挡土墙发生倾覆破坏时,倾覆端侧向土压力普遍增大,整体呈抛物线形式,沉降端土压力普遍减小;单拉筋条件下的沉降破坏,随着沉降量的增加,拉筋应力逐渐增大,倾覆端土压力在拉筋作用下呈现出倾覆破坏时的土压力分布,沉降端土压力整体呈先增后减的趋势且拉筋上部土压力变化幅度远大于拉筋下部;多拉筋条件下的沉降破坏,上部拉筋钢筋应力迅速减小,下部拉筋迅速增大,其墙背土压力与单拉筋条件下的墙背土压力相似,因此,在易发生不均匀沉降地段的对拉式挡土墙应加强下部拉筋及挡土墙墙身的强度。
Abstract: To study the mechanics response law of mutually anchored retaining wall in unstability, indoor model tests were designed to monitor and analyze changing rules of lateral earth pressure distribution of wall and the changing rules of anchor-bar stress, in the case of overturning and destruction. The results show that, when the tied double retaining wall overturns, end later earth pressures of overturns increase generally, overall forms parabolic, earth pressures of settlement end generally decreases. Under the condition of single rebar, when settlement destruction of the tied double retaining walls happens, with the increase of settlement, rebar stress is increased gradually, under the reaction of rebar, side of overturnings shows earth pressure distribution as overturning, earth pressures of settlement end shows a trend of increasing after decreases first, and earth pressure in upper brace changes bigger than the lower brace; under the condition of multi-strand rebar, when settlement destruction of the tied double retaining walls happens, steel bar stress of upper rebars decreases rapidly, the lower increases quickly, the earth pressure is similar with single rebar, therefore, the tied double retaining wall should strengthen the lower rebar and strength of retaining wall when area easily occurs uneven settlement.
高 路,陆晓彤,高 扬,王小惠,王 菁
摘 要:对三组钢筋混凝土梁在外荷载和服役环境下的耐久性能进行了试验室模拟研究。运用电化学方法对试件中不同涂层钢筋和无涂层钢筋的阻抗进行了测试和等效电路模拟,结合不同试件的裂缝分布,对模拟结果进行了分析。结果表明,环氧涂层能提高钢筋的耐腐蚀性;加载形式不同会对试件钢筋锈蚀产生不同影响;随盐水腐蚀时间的增加,试件中不同厚度涂层钢筋的抗锈蚀能力也有不同程度的退化。
Abstract: Laboratory simulation research on the durability behaviour of the three groups of reinforced concrete (RC) beams external load and environment attacks was studied, test and equivalent circuits modeling of impedance for specimen containing different epoxy-coated reinforcing bar and uncoated reinforcing bars by using electrochemical method are carried out, that simulation results are analyzed by combining with cracks distribution of different specimens. The results show that, epoxy coating can provide effective anti-corrosion protection for the reinforcing bars; the corrosion of the reinforcing bars in RC test specimens is influenced by external load. Deterioration of the anti-corrosion protection for reinforcing bars with different coating thicknesses in test specimens is shown with the increase of the simulated seawater solution attack.
曹天骥1,2,钱春香1,2,郭景强3,曲 军3
摘 要:结合一定条件下的水泥基材料泛碱处理措施与计算机图像分析技术,提出了一种定量表征水泥基材料泛碱程度的方法。基于该项方法,研究活性矿物掺合料偏高岭土对水泥基材料泛碱问题的影响。同时采用热重分析测试方法分析不同掺量偏高岭土的水泥基材料内部泛碱物质含量,并研究了偏高岭土对材料力学性能的影响。结果表明,适宜偏高岭土可以有效地抑制水泥基外墙系统的泛碱问题并保持其良好的力学性能。
Abstract: A quantitative method to characterize the degree of efflorescence in cement-based material is established based on computer image analysis technology and efflorescence treatment. According to this method, the influence of active mineral admixture-metakaolin on resist efflorescence for cement-based material is studied. Meanwhile, the efflorescence substance in cement-based material with different dosage of metakaolin is tested by TG, and the influence of metakaolin on mechanical properties of materials is investigated. The results indicate that, the proper dosage of metakaolin can effectively maintain the performance of anti-efflorescence and acquire better mechanics for cement-based external wall system.
张维维1,程建杰1,张 源2,何嘉鹏1
摘 要:以南京地区冬季的室外空气综合温度为计算条件,利用FLUENT软件模拟分析了空心混凝土砌块、EPS外保温、复合相变混凝土砌块应用于南向外墙时对空调房间和非空调房间室内热环境的影响。研究结果表明:对于空调房间和非空调房间,相变石膏板内置时的利用效果均优于外置;对于空调房间,EPS外保温和内置相变温度为19℃的相变石膏板的复合相变混凝土砌块下的内壁面热流波幅分别较空心混凝土砌块减小73%、43%,而房间总散热量分别较空心混凝土砌块减小6%、45%;对于非空调房间,内置相变温度为15℃的相变石膏板的复合相变混凝土砌块下的室内空气平均温度分别较空心混凝土砌块和EPS外保温提高2.45℃和2.24℃,而温度波幅分别较空心混凝土砌块和EPS外保温减小82%和51%。
Abstract: The outdoor air complex temperature in winter in Nanjing as the calculation conditions, the FLUENT software was used to simulate and analyze the effect of the hollow concrete block (HCB), EPS external insulation (EPS) and the composite phase change concrete block (PCCB) applied in the south facade on the indoor thermal environment of rooms with air conditioners and without air conditioners. The results show that, for the rooms with air conditioners and without air conditioners, the utilization effect of the phase change plasterboard (PCB) in internal putting was better than external putting; for the room with air conditioners, the amplitudes of heat flux on the inner wall surface of EPS and PCCB (the PCB was put in the inner hole, the phase change temperature was 19℃) decreased by 73% and 43% respectively than HCB, and the total heat emission of the room decreased by 6% and 45% respectively than that of HCB; for the room without air conditioners, the average temperature of indoor air of the room with PCCB (the PCB was put in the inner hole, the phase change temperature was 15℃) increased by 2.45℃ and 2.24℃ respectively than HCB and EPS, and the amplitude of the temperature of the indoor air decreased by 82% and 51% respectively than that of HCB and EPS.