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一、负温混凝土外加剂负温混凝土外加剂通常由防冻剂(亚硝酸钠、尿素、氯化钠、碳酸钾等)、早强剂(硫酸钠、三乙醇胺等)和减水剂(如NF、NNO等)复合而成。防冻剂的作用是降低液相的冰点,保证水化作用的持续进行。早强剂用来促进水泥的硬化,使混凝土在受冻前具有一定的强度。而减水剂降低混凝土中的含水量,提高其密实性。根据庆阳地区冬季气温的变化和油田冬季施工的实际及材料供应情况,考虑了三个配制-10℃负温混凝土的方案: 1.NaCl1％+三乙醇胺0.05％(占灰重量),用于大气温度不低于-10℃的素混凝土; 2.NaCl1％+NaNO_21％+三乙醇胺
A. Negative temperature concrete admixtures Negative temperature concrete admixtures are usually made of antifreeze (sodium nitrite, urea, sodium chloride, potassium carbonate, etc.), early strength agents (sodium sulfate, triethanolamine, etc.) and water reducing agents (such as NF , NNO, etc.) compounded. The role of antifreeze is to reduce the freezing point of the liquid phase and to ensure the continued hydration. The early strength agent is used to promote the hardening of the cement, so that the concrete has a certain strength before freezing. The water reducing agent reduces the moisture content in the concrete and improves its compactness. Based on the changes of winter temperature in Qingyang area and the actual conditions and material supply of winter oilfield construction, three schemes for the preparation of negative temperature concrete at -10°C were considered: 1. NaCl1% + triethanolamine 0.05% (ash weight) for The plain concrete whose atmospheric temperature is not lower than -10°C; 2.NaCl1%+NaNO_21%+triethanolamine