高寒地区水电站水工混凝土耐久性研究

Study on durability of hydraulic concrete for large hydropower station in the alpine region

高原地区具有独特的气候条件、原材料特点以及施工方法,高原、高寒、低压的气候特征将会对水工混凝土的耐久性和服役寿命产生较大影响。笔者结合当地水工混凝土可能经受的干湿冻融循环、碳化、化学侵蚀等耐久性问题,开展混凝土冻融循环破坏和干湿循环-冻融协同作用、碳化-冻融协同作用、化学侵蚀-冻融协同作用等多种因素破坏的试验。试验后得知:冻融循环和干湿循环的叠加作用对混凝土性能的影响不是二种因素之间的简单叠加,而是会产生放大效应。无论是先碳化后冻融还是先冻融后碳化,其碳化深度总体来说都随着水胶比的增加而增大。尽管混凝土试件经受多次冻融循环后,外观、质量以及相对动弹模变化不大,但强度劣化十分严重,建议采用性能损耗率或降低率等指标来表征混凝土的冻融耐久性。研究水工混凝土的耐久性,对保障高寒地区水电站水工混凝土质量起到了良好的指导作用。

Plateau areas have unique climatic conditions,characteristics of raw materials and construction methods.The climatic characteristics of plateau,high cold and low pressure will have a great impact on the durability and service life of hydraulic concrete.Combined with the durability problems that local hydraulic concrete may undergo such as dry-wet cycling,carbonization,chemical erosion,etc.,single factor damage of concrete freeze-thaw cycles and multi-factor damage experiments such as dry-wet cycle-freezing-thawing synergy,carbonization-freezing-thawing synergy,chemical erosion-freezing-thawing synergy are carried out.The study on the durability of hydraulic concrete plays a good guiding role in ensuring the quality of hydraulic concrete for hydropower stations in the alpine region.