摘要
采用相同的水胶比、含气量、高频振捣方法和试件尺寸等,成型全级配和二级配混凝土大试件,进行冻融、强度和超声波波速等试验。试验结果表明,全级配混凝土的抗冻性低于二级配混凝土,经200次冻融循环后,全级配混凝土的不可恢复变形约为二级配混凝土大试件变形的三倍,其强度和超声波波速的下降速率均大于二级配混凝土。全级配混凝土内部高含量的大粒径骨料对其抗冻性有负面作用。因此,湿筛混凝土的抗冻性不能完全代表坝体混凝土的抗冻性,这在混凝土坝的设计和施工中应引起注意。
Freeze-thaw tests,mechanical tests,ultra-sonic wave velocity and deformation measurements were conducted on two groups of concrete samples with maximum aggregate sizes of 120mm and 40mm.Each group was molded under the same conditions of water-cement ratio,air content,high-frequency vibration manner and sample size.The test results show that the frost resistance of 120mm sample is poorer than that of 40mm sample.The irrecoverable expansion deformation of 120mm sample after 200 freeze-thaw cycles is about three times that of 40mm sample,the losses in strength and ultra-sonic wave velocity are also larger.The high-content large-sized aggregates in dam concrete have adverse effect on its frost resistance.Thus,the frost resistance of wet-sieved concrete can not well represent the frost resistance of dam concrete,which deserves an attention in design and construction of concrete dam.
出处
《水力发电学报》
EI
CSCD
北大核心
2011年第1期139-143,共5页
Journal of Hydroelectric Engineering
基金
国家自然科学基金资助项目(50579075)
水利部公益性行业科研专项(200701041)
