冻融损伤混凝土力学性能研究与等效冻融循环次数计算模型

Study on Mechanical Properties of Frost-damaged Concrete and Calculation Model of Equivalent Freeze-thaw Cycles

为研究人工气候环境下冻融损伤混凝土的力学性能退化规律,以冻融循环次数(FTCs)、混凝土强度为设计参数,共设计制作了21组混凝土试块,先后对其进行冻融循环试验与轴心受压试验。结果表明:随冻融循环次数的增加,抗压强度逐渐降低,且降低速率逐渐增大;不同强度等级混凝土的相对动弹性模量P均逐渐降低,且降低速率大致相等;随设计混凝土强度等级的增大,相对抗压强度增加,且增加速率逐渐增大;当冻融循环次数<100时,相对动弹性模量基本不变;当冻融循环次数>100时,相对动弹性模量则逐渐增大。基于试验结果,得到了不同冻融条件下的等效冻融循环次数计算模型,实现了不同冻融条件研究结果的相互利用与对比验证。

In order to study the degradation law of mechanical properties of frozen-thawed damage concrete in artificial climate,using the number of freeze-thaw cycles(FTCs)and concrete strength as design parameters,a total of 21 sets of cubic concrete test blocks were designed and manufactured.The freeze-thaw cycle test and the axial compression test were successively performed.The experimental results show that as the number of FTCs increases,the cubic compressive strength gradually decreases,and the decrease rate gradually increases.And the relative dynamic elastic modulus P of different strength levels gradually decreases,and the decrease rate is approximately equal.With the increase of design concrete strength grade,the relative compressive strength increases gradually,and the increasing rate increases gradually.The relative dynamic elastic modulus is basically unchanged when the number of FTCs is less than 100,and gradually increases when the number of FTCs is more than 100.Based on the test results,according to the principle of the same compressive strength loss,the artificial climate rapid freeze-thaw technique test conditions and the freeze-thaw conditions of"fast freeze method"are equivalent,and the calculation model of the equivalent FTCs under different freeze-thaw conditions is obtained,so as to realize the mutual utilization and comparative verification of the research results under different freeze-thaw conditions.