万家寨水利枢纽工程混凝土施工温度控制

Temperature Control of Concrete Construction for Wanjiazhai Dam Project

万家寨水利枢纽工程地处干旱、半干旱的黄土高原丘陵区 ,夏季炎热 ,冬季严寒 ,且温差较大 ,给混凝土施工温度控制带来很大难度。文章较详细的介绍了本工程混凝土施工温度控制的技术措施、施工措施以及温控效果。

Wanjiazhai Dam Project lies in loess plateau of arid and semi arid rolling region,where it is burning hot in summer,freezing cold in winter and where,there is great temperature difference,all these conditions make concrete construction very difficult.In this paper,the technological measures and construction measures of temperature control for concrete construction and the effect of temperature control are introduced in detail.The technological measures include:selecting the rational mix proportion,admixing effectual water reducing agent,blending the fly ash,using the cement of a low hydration heat,enlarging the maximum grain size of aggregate,rationally determining the sand and total aggregate ratio and adopting the concrete of a low slump.The construction meaures for temperature control differ with different season,in summer,they have:temperature reducing and precooling of aggregate,keeping coldness by insulation,rational arranging the casting time,cooling by water circulation within dam and blending cold water and ice piece for concrete construction;in winter,they have:admixing antifreeze agent,cleaning snow,frost and ice which adhered to the aggregate before which are to be stored,decreasing the temperature fluctuation at outlet of mixer;and in the spring and autumn,some corresponding measures are taken as well.The results of temperature monitoring inside the dam and observation on concrete crack show that the great temperature variation of the dam body conforms to general regime of the gravity dam and that there has not been found any large and harmful traverse cracks.