| 付传清,屠一军,金贤玉,张俊芝,闫东明.荷载和环境共同作用下混凝土中氯离子传输的试验研究[J].水利学报,2016,47(5):674-684 |
| 荷载和环境共同作用下混凝土中氯离子传输的试验研究 |
| Experimental study on chloride transport in concrete under environmental and loading coupling conditions |
| 投稿时间：2015-07-24 |
| DOI：10.13243/j.cnki.slxb.20150812 |
| 中文关键词: 混凝土 荷载作用 环境条件 氯离子 扩散系数 |
| 英文关键词: concrete loading effect environmental condition chloride ions diffusivity |
| 基金项目:国家973计划项目(2015CB655103);国家自然科学基金项目(51279181,51308503,51379186);中国博士后基金特等资助(2015T80615) |
|
| 摘要点击次数: 1887 |
| 全文下载次数: 98 |
| 中文摘要: |
| 荷载和环境作用影响着混凝土中的氯盐传输过程和混凝土结构的服役寿命。采用弹簧加载系统对8根钢筋混凝土梁施加极限抗弯承载力28%、22%、16%和10%的持续弯曲荷载,并测定混凝土梁跨中部位的局部应变;氯盐侵蚀试验在多功能人工模拟环境试验箱中进行,4根混凝土梁置于5%的NaCl溶液并在环境温度为50 ℃下进行浸泡试验,其余4根钢筋混凝土梁在全自动干湿循环试验箱中进行干湿循环试验,干燥过程中环境相对湿度为60%。氯盐侵蚀60 d后对混凝土梁受拉区和受压区取粉分析氯离子浓度。结果表明:与未承受荷载混凝土试件的氯离子传输速率相比,拉应变达到526με时氯离子扩散系数达到未承受荷载时的2.4倍,压应变达到90 με时氯离子扩散系数无明显改变,而当压应变达到175 με 时氯离子扩散系数降低为无荷载作用时的0.4倍,拉应力加速了氯离子的传输速率,而压应力在一定范围内能够抑制氯离子的传输;且干湿循环条件下混凝土的氯离子传输速率明显高于浸泡条件的混凝土。“拉应力+干湿循环”条件对氯离子的传输影响最大;混凝土局部应变与氯离子扩散系数的相关性较好,能够反映荷载作用对氯盐传输的影响。在一定应变范围内,氯离子扩散系数随拉应变的增大而提高,随压应变增大而降低。 |
| 英文摘要: |
| Abstract:Chloride transport process and service life of concrete structures are affected by surrounding environment and loading conditions. Sustained bending load of 28%, 22%, 16% and 10% of ultimate bending load was applied on 8 reinforced concrete beams by a spring loading system, respectively. Meanwhile, the local strains on the mid-span height of RC beams were measured. Immersion tests were conducted on 4 beams while drying-wetting tests were on the other 4 beams in an artificial climate chamber under the condition of chloride solution of 5% , environment temperature of 50℃ and RH of 60%. An automatic drying-wetting device was used to simulate the ocean tide. After 60 days, to determine the chloride ions concentration, the concrete specimens were drilled at tension zone and compression zone in the mid-span of the RC beam. Compared with the chloride transport process in unstressed concrete, chloride transport process was accelerated by tensile stress and suppressed by compression stress. The chloride diffusivity in concrete with tension strain of 526με is about 2.4 times faster than that in unstressed concrete, and the chloride diffusivity of concrete with compression strain of 90με is the same as the unstressed concrete, but the chloride diffusivity of concrete with the compression strain of 175με is 0.4 times slower than the unstressed concrete. And the chloride transport in RC beams under drying-wetting condition is faster than the ones under immersion condition. Among the different loading and environmental condition couplings, tension stress and drying-wetting coupling is the most serious condition for chloride transport. It can be found that the local strain of concrete is in good correlation with chloride ion diffusion coefficient,which can reflect the effect of loading on chloride transport. Within a range of strain in concrete, chloride diffusion coefficient increases with the increasing ensile strain,and decreases with the increasing compressive strain. |
|
查看全文
查看/发表评论 下载PDF阅读器 |
| 关闭 |
|
|
|