摘要
通过对受冻融混凝土试件进行单轴动态抗压试验,分析了冻融次数(0、25、50和75次)及应变速率(10^(-5)s^(-1)、10^(-4)s^(-1)和10^(-3)s^(-1))对混凝土抗压强度、峰值应变和应力-应变曲线的影响。结果表明:不同应变速率下受冻融混凝土的破坏特点有所差异,随着应变率的提高,试件断面更加平整,有较多粗骨料发生破坏;相同冻融次数下,随着应变率的增大,抗压强度明显增加,而峰值应变减小,应力-应变全曲线的峰值点呈前移和上升的趋势,曲线上升段斜率逐渐增大且长度也随之增大,下降段越为陡峭,表现明显的脆性特点;相同应变率下,随着冻融次数的增加,抗压强度均有所降低,而峰值应变逐渐增大,应力-应变全曲线的峰值点表现为明显下降和后移的趋势,其曲线下包面积减小,吸收能量的能力变差;通过对试验结果分析,建立了考虑应变率影响的受冻混凝土受压应力-应变曲线方程。
The uniaxial dynamic compression experiments are conducted on frozen-thawed concrete specimens,the effects of freeze-thaw cycles（ 0,25,50 and 75 times） and strain rates（10^-5s^-1、10^-4s^-1 and 10^-3s^-1） on the compressive strength,peak strain and stress-strain curve are systematically analyzed. The test results show that the failure model of frozen-thawed concrete at various strain rates are different,and with the increasing of strain rates the fracture section of specimens turns to be more flat and many coarse aggregates are damaged; Under the same number of freeze-thaw,with the increasing of strain rate,the compressive strength increases,the peak stain decreases,the peak of the stress-strain curve shows a trend of moving to the upper left,the ascending branch becomes longer whose slope gradually increases,and the descending branch changes in a steepening trend,which shows obvious brittleness;Under same strain rate,as the increase of freeze-thaw cycles,the compressive strength decreases,the peak stain increases,the peak of the stress-strain curve significantly shifts to the below and right,and the area under the stress-strain curve is decreased,which indicates the energy-absorbing capacity decreases;Based on the experimental data,the compressive stress-strain curve equation considering the effects of strain rate and freeze-thaw cycles is proposed.
出处
《硅酸盐通报》
CAS
CSCD
北大核心
2017年第12期4277-4283,4301,共8页
Bulletin of the Chinese Ceramic Society
基金
国家自然科学基金(51479174)
水沙科学与水利水电工程国家重点实验室开放基金(sklhse-2017-C-01)
关键词
冻融循环
混凝土
动态性能
应变率
应力-应变曲线
freeze-thaw cycle
concrete
dynamic behavior
strain rate
stress-strain curve
