基于不同环境下掺粉煤灰混凝土耐久性试验研究
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摘要
混凝土耐久性是反应其内部材料性能和抵抗外部环境作用的一个综合性评价指标。为了研究不同水胶比及粉煤灰掺量混凝土的耐久性能,在考虑各地气候及环境的基础上,以3种水胶比及粉煤灰掺量的混凝土作为研究对象,在室内设计了模拟现场侵蚀环境的3种耐久性试验,结果表明:不同环境下混凝土侵蚀机理不同,自然浸泡环境下以化学腐蚀为主,冻融循环作用下混凝土试件则主要受到物理破坏,硫酸盐溶液中进行干湿循环时试件同时受到复杂的物理化学反应。三类试件中以水胶比是0.30,粉煤灰掺量为15%的试件在各类环境下的耐久性最好。混凝土在硫酸盐溶液中会生成膨胀产物钙矾石,对试件产生较大的膨胀压力。
The durability of concrete is a comprehensive evaluation index of its internal material properties and resistance to external environmental effects.In order to study different water-binder ratio and fly ash content concrete durability performance,on the basis of considering local climate and environment,with three kinds of water-binder ratio,fly ash content concrete as the research object,three kinds of durability tests of the simulation of erosion environment indoors were designed in the laboratory.Results show concrete erosion mechanism is not same in different environment.Under the condition of natural immersion,the concrete specimens are mainly subject by chemical corrosion.However,freezing and thawing cycle under the action of its is mainly affected by physical damage,complex physical and chemical reactions were also at the simultaneously performed in sulfate solution during the wetting and drying cycles.Water/cement ratio is 0.30 and15% fly ash specimen have best durability in all kinds of environment.The concrete product will generate expansive ettringite in sulfate solution and result in high pressure expansion on the specimen.
The durability of concrete is a comprehensive evaluation index of its internal material properties and resistance to external environmental effects.In order to study different water-binder ratio and fly ash content concrete durability performance,on the basis of considering local climate and environment,with three kinds of water-binder ratio,fly ash content concrete as the research object,three kinds of durability tests of the simulation of erosion environment indoors were designed in the laboratory.Results show concrete erosion mechanism is not same in different environment.Under the condition of natural immersion,the concrete specimens are mainly subject by chemical corrosion.However,freezing and thawing cycle under the action of its is mainly affected by physical damage,complex physical and chemical reactions were also at the simultaneously performed in sulfate solution during the wetting and drying cycles.Water/cement ratio is 0.30 and15% fly ash specimen have best durability in all kinds of environment.The concrete product will generate expansive ettringite in sulfate solution and result in high pressure expansion on the specimen.
引文
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[2]周纲,李少荣,王掌军,等.盐渍土地区混凝土腐蚀状况调查分析[J].建筑科学与工程学报,2011,28(4):121-126.
[3]弋雪良,苏文德,陆采荣.气候变化条件下水工混凝土的抗冻性能[J].水利水电科技进展,2015,35(6):37-40.
[4]王晓初,金明君,杨春峰.混凝土耐久性研究现状综述[J].混凝土,2006(2):31-33.
[5]高原,张君,韩宇栋.干湿交替下混凝土内部相对湿度变化规律[J].建筑材料学报,2013,16(3):375-381.
[6]元成方,牛荻涛,齐广政.干湿循环机制下碳化混凝土氯离子侵蚀试验研究[J].西安建筑科技大学学报(自然科学版),2012,44(3):339-344.
[7]张立明,余红发,何忠茂.沿湖地区混凝土氯离子扩散性[J].中南大学学报(自然科学版),2011,42(6):1752-1755.
[8]张益杰,赵铁军,张鹏,等.冻融环境下水灰比及掺合料对短期混凝土断裂能的影响研究[J].硅酸盐通报,2015,34(11):3084-3089.
[9]方从启,张俊萌,段桂珍.素混凝土抗冻性能试验研究[J].混凝土,2014(2):5-8.
[10]乔宏霞,师莹莹,陈丁山,等.混凝土在硫酸盐中的腐蚀模型[J].重庆大学学报,2015,38(6):129-137.
[11]严福章,于国明,胡瑾,等.混凝土的抗压强度和抗硫酸盐侵蚀性能的正交试验研究[J].混凝土,2015(3):34-37.
[12]乔宏霞.混凝土抗硫酸盐腐蚀耐久性的评价方法研究[D].兰州,2007:130-132.