低温冻融循环对陶粒混凝土动态力学性能的影响

Influence of Low Temperature Freeze-Thaw Cycle on Dynamic Mechanical Properties of Ceramsite Concrete

为了研究冻融循环温度和循环周次对陶粒混凝土动态力学性能的影响,开展了冻融循环试验和Hopkinson束杆动态压缩试验。冻融循环温度上限取+10℃,下限取为-20~-60℃,间隔-10℃,试样尺寸150 mm×150 mm×100 mm,对冻融循环后的试样进行动态压缩试验。结果表明,增加冻融循环周次和降低冻融循环温度,均加深了陶粒混凝土的损伤,使其动态抗压强度降低。当循环周次达到30次时,陶粒混凝土的弹性模量下降至未冻融前的60%左右,混凝土弹性模量随冻融循环最低温度的降低基本呈线性递减趋势。陶粒混凝土抗压强度随着冻融循环周次增加或冻融循环最低温度降低而降低,且最大应力所对应的应变随着抗压强度的降低而增大。

With the purpose of studying the influences of the freeze-thaw cycle temperature and cycle times on the dynamic mechanical properties of ceramsite concrete,the freeze-thaw cycle test and the Hopkinson pressure bar compression test were performed.The upper limit of the freeze-thaw cycle temperature was+10℃and its lower limit was-20℃to-60℃with the interval of-10℃.The sample size used in the tests is 150 mm×150 mm×100 mm,the dynamic compression test on samples after freeze-thaw cycle were carried out.The results show that either increasing the freeze-thaw cycle times or decreasing the freeze-thaw cycle temperature deepens on the damage of ceramsite concrete,reduces its dynamic compressive strength.When the cycle times reach 30 times,the elastic modulus of ceramsite concrete drops to approximately 60%of that prior to freeze-thaw cycle.Basically,the concrete elastic modulus follows a linear decreasing trend with the decrease of the minimum freeze-thaw cycle temperature.In addition,the compressive strength of ceramsite concrete declines with either the increase of the freeze-thaw cycle times or the reduction of the lowest freeze-thaw cycle temperature.Moreover,the strain corresponding to the maximum stress increases when the compressive strength decreases.