摘要
为了提高高寒地区冬季施工中泵送混凝土的性能,研究两种坍落度、两种防冻剂的混凝土在自然变负温养护和恒负温养护条件下抗压强度发展规律。结果表明:自然变负温养护由于昼夜温差的变化导致掺防冻剂混凝土7d强度均明显高于恒负温7d的强度,高防冻组分的防冻剂能够促进自然变负温养护下混凝土强度持续增长,也抑制了标准养护条件下混凝土后期强度的发展。利用高效减水剂或增加一定的用水量改善混凝土的工作性时,由于凝结时间的延长,负温下混凝土抗压强度会受到明显影响,混凝土内部易冻结损伤。与自然变负温养护条件相比,利用恒负温养护制度检验防冻剂质量时会因防冻剂类型不同造成质量判断上的差异。采用含高减水组分的防冻剂,并延长正温下的养护时间,有利于提高冬季施工中泵送混凝土的性能。
In order to improve the properties of pumping-concrete for winter construction in cold region, the development of compressive strength of concrete was investigated at different slump with two kinds of anti- freezing admixture undergoing two curing conditions, which are outdoor varied negative temperature（OVid） and constant negative temperature（CNT）. The results showed that the compressive strength of concrete with anti-freezing admixture at 7 days under OVNT condition were higher than those under CNT. High anti-reezing agent admixture can promote the development of compressive strength of concrete at OVNT condition but hinder the strength increase of concrete at standard curing condition. When adding superplasticizer and more water to improve the workability of concrete, the compressive strength of concrete at negative temperature was affected distinctly and the frost damage was easily happened inside concrete due to the delay of the setting time of concrete. Compared with OVNT condition, CNT condition used to examine the quality of anti-freezing admixture will cause misjudgment due to different type anti-freezing admixture. Using high water-reducing anti-freez- er and delaying the curing time of concrete at above-zero temperature will benefit to improve the properties of pumping concrete in winter construction.
出处
《低温建筑技术》
2009年第4期1-4,共4页
Low Temperature Architecture Technology
关键词
混凝土
自然变负温养护
恒负温养护
concrete
outdoor varied negative temperature
constant negative temperature
