Using strain to evaluate influence of air content on frost resistance of concrete
Using strain to evaluate influence of air content on frost resistance of concrete
复制标题
利用应变评价含气量对混凝土抗冻性的影响
DOI：
10.1016/j.coldregions.2018.09.012
复制
发表时间：
2019-01-01
影响因子：
4.1
通讯作者：
Cheng, Xin
中科院分区：
文献类型：
--
作者：
Du, Peng;Yao, Yan;Cheng, Xin
为了保证混凝土具有适当的抗冻性，需要在混凝土中设计具有确定几何结构的人工空隙系统。应变作为混凝土抗冻性能的评价指标，具有实时无损监测、准确性高、连续性好、人工干预误差小等优点，可用于评价含气量对混凝土抗冻性能的影响。随着冻融循环的进行，应变滞回曲线上移，表明混凝土基体中产生了持续累积的不可逆残余应变。含气量较大（4.5%和6.9%）的混凝土残余应变值明显较低，说明其变形和冻融破坏程度较小。不仅如此，残余应变还能反映混凝土早期抗冻性的一些信息，与传统参数相比有其独特的优势。此外，本研究定义的冻结特征温度变化Δ T-f和表观冻胀系数变化Δ α（f）可以分别表征混凝土的冻融破坏程度和抗冻性。
In order to ensure proper frost resistance, a design of artificial air-void system with defined geometric structure is needed in concrete. Strain, which may have certain inherent advantages compared to traditional test parameters, such as real-time nondestructive monitoring, more accurate and continuous with little error that is caused by manual intervention and so on, was used to evaluate influence of air content on frost resistance of concrete in this study. With the process of freeze-thaw cycles, the moving up strain hysteretic loop indicates that the continued accumulated and irreversible residual strain is generated in the concrete matrix. The residual strain values of concrete with more air content (4.5% and 6.9%) are obviously lower, indicating that their deformation and freeze-thaw damage degree are smaller. And not only that, residual strain is able to reflect some information of concrete early frost resistance, owning its special advantage compared with traditional parameters. Besides, the variation of freeze characteristic temperature Delta T-f and the variation of apparent frost heaving coefficient Delta alpha(f) defined in this study are able to characterize the freeze-thaw damage degree and frost resistance of concrete respectively.