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摘要: 为全面系统地研究混凝土在应力与腐蚀介质耦合作用下的环境响应, 利用专门设计的应力腐蚀加载试验装置, 分析了高性能混凝土在三分点加荷与腐蚀溶液同时作用下的性能衰减规律, 及各试验结果对应力腐蚀评价指标的敏感性。结果表明, 在一定的试验周期内, 受应力腐蚀高性能混凝土的抗折强度损失率在10%以上, 而抗压强度及质量基本不变, 因此在评价其应力腐蚀性能指标方面以抗折强度损失率最为敏感。Abstract: The stress-corrosion damage of concrete is the coupled action result of stress and corrosion medium, and its study is in exploratory stage. With the loading test equipment of stress-corrosion, the attenuation discipline of high-property-concrete's performance under the action of three-points loading and corrosion solution was studied, the sensitivity of testing results to the stress-corrosion-evaluation indices was analyzed. The results indicate that the loss rate of high-property-concrete's bending strength under the action of stress-corrosion is over 10%, its compression strength and quality usually have no change, the bending strength loss rate is most sensitive to the evaluation indices of concrete's stress-corrosion performance.
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Key words:
- pavement engineering /
- high-property-concrete /
- stress-corrosion /
- evaluation indices
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表 1 普通硅酸盐水泥化学成分
Table 1. Chemical composition of cement
化学成分 SiO2 Al2O3 Fe2O3 CaO MgO f-CaO 碱含量 不溶物 烧失量 含量/% 21.68 5.34 3.47 64.98 1.17 0.58 1.04 0.07 2.68 表 2 粉煤灰化学成分
Table 2. Chemical composition of fly ash
化学成分 SiO2 Al2O3 Fe2O3 CaO MgO SO3 K2O Na2O 烧失量 含量/% 59.34 20.06 9.70 4.18 2.07 0.79 2.17 0.71 2.3 表 3 腐蚀介质及浓度
Table 3. Corrosion media and chroma
腐蚀介质种类 腐蚀介质浓度/% 备注 Na2SO4 10 工业硫酸钠加入水中 MgSO4 10 分析纯硫酸镁加入水中 MgCl2 27 分析纯氯化镁加入水中 自来水 —— —— 表 4 应力腐蚀试验因素与水平
Table 4. Factors and levels of stress-corrosion test
水平 因素 粉煤灰掺量/% 水胶比 应力水平 腐蚀溶液 1 0 0.33 0.15 自来水 2 10 0.30 0.30 Na2SO4 3 20 0.27 0.45 MgSO4 4 30 0.25 0.60 MgCl2 表 5 混凝土配合比及部分试验结果
Table 5. Concrete mixture ratio and partial experiment results
序号 1 m3混凝土材料用量/kg 工作性能 抗压强度/MPa 水泥 粉煤灰 水 砂 石子 外加剂 坍落度/mm 扩展度/mm 7 d 28 d 60 d 1 450 0 150 820 950 6.75 15 未坍落 48.8 59.7 67.0 2 405 45 150 810 950 6.75 180 370 47.8 59.0 70.3 3 360 90 150 800 950 6.75 210 400 45.6 65.2 73.2 4 315 135 150 790 950 6.75 195 390 35.6 56.1 71.5 5 500 0 150 810 950 7.50 5 未坍落 56.5 64.9 76.2 6 450 50 150 800 950 7.50 215 410 59.3 71.3 74.8 7 400 100 150 790 950 7.50 240 470 55.0 77.6 82.3 8 350 150 150 780 950 7.50 240 545 47.2 71.8 77.2 9 550 0 150 800 950 8.25 30 未坍落 57.0 67.3 75.7 10 495 55 150 790 950 8.25 235 465 58.9 83.5 84.8 11 440 110 150 780 950 8.25 235 500 61.4 72.4 87.8 12 385 165 150 770 950 8.25 245 600 52.3 70.2 79.6 13 600 0 150 790 950 9.00 180 未坍落 60.6 64.8 51.9 14 540 60 150 780 950 9.00 220 480 58.6 70.0 77.5 15 480 120 150 770 950 9.00 230 520 60.9 67.3 81.4 16 420 180 150 760 950 9.00 240 510 44.5 60.6 79.2 注: 混凝土中外加剂组成为(占胶结料质量) : 1.0%UNF-5 (粉剂) +0.5%SDB (水剂)。 表 6 质量损失试验结果
Table 6. Test result of quality loss
试验序号 标养60 d, 腐蚀介质中浸泡120 d 标养60 d, 应力腐蚀120 d 浸泡前平均质量/g 浸泡后平均质量/g 质量损失/% 浸泡前平均质量/g 浸泡后平均质量/g 质量损失/% C1 639.6 642.4 -0.438 642.2 644.7 -0.389 C2 652.8 655.1 -0.352 654.0 656.5 -0.382 C3 645.7 647.3 -0.248 933.9 635.3 -0.221 C4 638.6 640.0 -0.219 634.8 635.8 -0.158 C5 639.6 641.0 -0.219 636.5 636.8 -0.047 C6 642.6 644.4 -0.280 638.3 641.0 -0.423 C7 643.6 645.6 -0.311 637.4 639.8 -0.377 C8 644.1 644.6 -0.078 638.6 639.6 -0.157 C9 640.1 643.2 -0.484 634.3 637.3 -0.473 C10 643.5 644.9 -0.218 647.2 648.3 -0.170 C11 638.0 639.1 -0.172 636.3 636.9 -0.094 C12 639.0 640.3 -0.203 638.5 640.8 -0.360 C13 649.2 652.6 -0.524 639.2 642.8 -0.563 C14 639.9 641.5 -0.250 642.4 644.0 -0.249 C15 632.8 633.7 -0.142 633.1 633.3 -0.032 C16 635.9 636.3 -0.063 642.9 644.2 -0.202 表 7 应力腐蚀抗压强度试验结果
Table 7. Test result of stress-corrosion compression strength
试验序号 标养180 d (fcu180) /MPa 标养60 d, 腐蚀介质中浸泡20 d (fcuc) /MPa 标养60 d, 应力腐蚀120 d (fcusc) /MPa 浸泡抗压强度损失/% 应力腐蚀抗压强度损失/% C1 86.3 88.9 83.0 -3.0 3.8 C2 93.9 98.4 94.8 -4.8 -1.0 C3 93.9 97.8 100.8 -4.2 -7.3 C4 94.7 92.3 102.7 2.5 -8.4 C5 81.2 87.0 85.3 -7.1 -5.0 C6 95.9 94.5 92.5 1.5 3.5 C7 103.6 100.5 97.3 3.0 6.1 C8 80.3 85.9 83.1 -7.0 -3.5 C9 84.8 77.5 87.1 8.6 -2.7 C10 99.7 101.9 97.3 -2.2 2.4 C11 99.8 98.3 102.3 1.5 -2.5 C12 102.0 98.4 97.0 3.5 4.9 C13 71.9 86.0 85.6 -19.6 -19.1 C14 96.9 93.4 87.5 3.6 9.7 C15 89.8 83.1 87.2 7.5 2.9 C16 105.0 98.9 96.6 5.8 8.0 表 8 应力腐蚀弯拉强度试验结果
Table 8. Test result of stress-corrosion flexural tensile strength
试验序号 标养60 d (fcf60) /MPa 标养180 d (fcf180) /MPa 标养60 d, 腐蚀介质中浸泡120 d (fcfc) /MPa 标养60 d, 应力腐蚀120 d (fcfsc) /MPa 腐蚀介质强度损失/% 应力腐蚀强度损失/% C1 8.90 9.31 8.59 7.82 7.73 16.00 C2 9.96 9.90 9.65 9.16 2.53 7.47 C3 10.34 10.92 8.54 8.57 21.79 21.52 C4 8.95 9.76 8.64 7.76 11.48 20.49 C5 10.61 9.98 9.65 8.99 3.31 9.92 C6 9.83 10.83 10.57 9.64 2.40 10.99 C7 10.17 10.63 9.14 8.40 14.02 20.98 C8 8.63 8.31 7.83 7.47 5.78 10.11 C9 9.65 9.76 9.02 8.63 7.58 11.58 C10 10.55 10.62 9.04 8.51 14.88 19.87 C11 10.32 11.42 9.98 9.69 12.61 15.15 C12 10.29 11.1 8.59 8.96 22.61 19.28 C13 8.55 9.18 8.76 8.03 4.58 12.53 C14 8.69 8.62 7.82 7.26 9.28 15.78 C15 8.79 9.96 8.38 7.83 15.86 21.39 C16 9.85 10.15 8.49 7.79 16.35 23.25 -
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