大温差、大湿差环境下硫酸钠半浸泡混凝土抗压与微观特性
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摘要
研究了西部大温差和大湿差的自然环境下,早期受5%和10%两种浓度硫酸钠溶液半浸泡28 d、56 d、84 d、112 d混凝土抗压强度。结果表明:与不浸泡试样28 d抗压强度相比,随着半浸泡时间的延长,不同浓度硫酸钠溶液半浸泡试样的抗压强度均呈递减趋势。10%硫酸钠溶液半浸泡试样28 d抗压强度损失达27.2%,半浸泡后期其抗压强度与5%溶液浓度半浸泡试样差别不大。扫描电镜(SEM)和XRD测试结果表明:半浸泡试样暴露于空气中的部分发生了无水硫酸钠结晶腐蚀,这也是半浸泡试样抗压强度降低的主要原因之一。
Under natural large temperature and relative humidity difference in the west of China,compressive strengths of twenty-eight days,fifty-six days,eighty-four days and hundred-twelve days for ordinary concrete partially submerged in 5% and 10% sodium sulfate solution at its early stages were studied. The results show that compressive strengths of specimens partially submerged in different concentrations of solution gradually decline as the extension of partially exposed time after comparing with that of unsubmerged specimens. Compressive strength of twenty-eight days for specimen partially submerged in 10% sodium sulfate solution decrease by 27. 2%,however the compressive strengths have no obvious difference with that of 5% solution as the extension of partially exposed time. SEM and XRD show that sodium sulfate crystallization erosion happens to the partially exposed area,and results in large compressive strength loss.
Under natural large temperature and relative humidity difference in the west of China,compressive strengths of twenty-eight days,fifty-six days,eighty-four days and hundred-twelve days for ordinary concrete partially submerged in 5% and 10% sodium sulfate solution at its early stages were studied. The results show that compressive strengths of specimens partially submerged in different concentrations of solution gradually decline as the extension of partially exposed time after comparing with that of unsubmerged specimens. Compressive strength of twenty-eight days for specimen partially submerged in 10% sodium sulfate solution decrease by 27. 2%,however the compressive strengths have no obvious difference with that of 5% solution as the extension of partially exposed time. SEM and XRD show that sodium sulfate crystallization erosion happens to the partially exposed area,and results in large compressive strength loss.
引文
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10马昆林,谢友均,龙广成.毛细用下硫酸盐溶液在混凝土中传输速率的实验研究.硅酸盐学报,2012;40(10):1448-1455Ma K L,Xie Y J,Long G C.Transportation velocity of sulfat solution in concrete under capillary effect.Journal of the Chines Ceramic Society,2012;40(10):1448-1455
11马昆林.混凝土盐结晶侵蚀机理与评价方法.长沙:中南大学,2009Ma K L.Mechanism and evaluation method of salt crystallization attack on concrete.Changsha:Central South University,2009
2高润东,赵顺波,李庆斌,等.干湿循环作用下混凝土硫酸盐侵蚀劣化机理实验研究.土木工程学报,2010;43(2):48-54Gao R D,Zhao S B,Li Q B,et al.Experimental study of the deterioration mechanism of concrete under sulfate attack in wet-dry cycles.China Civil Engineering Journal,2010;43(2):48-54
3梁咏宁,袁迎曙.硫酸钠和硫酸镁溶液中混凝土腐蚀破坏的机理.硅酸盐学报,2007;35(4):504-508Liang Y N,Yuan Y S.Mechanism of concrete destruction under soldium sulfate and magnesium sulfate solution.Journal of the Chinese Ceramic Society,2007;35(4):504-508
4施峰,汪俊华.硫酸盐侵蚀混凝土立方体的性能退化.混凝土,2013;281(3):52-54Shi F,Wang J H.Performance degradation of concrete cube attacked by sulfate.Concrete,2013;281(3):52-54
5孙迎召,牛荻涛,姜磊,等.干湿循环条件下混凝土硫酸盐侵蚀损伤分析.硅酸盐通报,2013;32(7):1405-1409Sun Y Z,Niu D T,Jiang L,et al.Damagelayer thickness of concret under wet/dry cycling measured by ultrasonic method.Building o the Chinese Ceramic Society,2013;32(7):1405-1409
6 Roman L,Andreas L.An accelerated sulfate resistance test fo concrete.Materials and Structures,2016;(49):3445-3457
7 Zhang J S,Zhang Y H,Feng L P,et al.Damage model of fresh concrete in sulphate environment.Journal of Central South University,2015;(22):1104-1113
8 Liu Z Q,Deng D H,Schutter G D.Does concrete suffer sulfate sal weathering?.Construction and Building Materials,2014;(66):692-701
9马昆林,龙广成,谢友均.硫酸盐半浸泡侵蚀下水泥基材料中腐蚀产物的实验研究.混凝土,2013;287(9):33-35Ma K L,Long G C,Xie Y J.Corrosion products of cementiou materials under sulfate partial soaking attack.Concrete,2013;287(9):33-39
10马昆林,谢友均,龙广成.毛细用下硫酸盐溶液在混凝土中传输速率的实验研究.硅酸盐学报,2012;40(10):1448-1455Ma K L,Xie Y J,Long G C.Transportation velocity of sulfat solution in concrete under capillary effect.Journal of the Chines Ceramic Society,2012;40(10):1448-1455
11马昆林.混凝土盐结晶侵蚀机理与评价方法.长沙:中南大学,2009Ma K L.Mechanism and evaluation method of salt crystallization attack on concrete.Changsha:Central South University,2009