冻融损伤喷射混凝土本构关系及微观结构

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摘要：采用棱柱体试件,通过快速冻融试验方法，对冻融损伤后同配合比普通混凝土、喷射混凝土
及钢纤维混凝十力一应变全电线讲行研力一应变关系中初美科 ☑ L
分析，得出循环后试件应力一应变全面线方程。结果表明：冻融衛环次数增加，受压应力一
应变曲线超于扁平;峰值应力降低,峰值应变增大,分别与冻融循环次数呈线性和指数变化。与普
通混凝土相比,喷射泥凝土峰值应力下降速率小,而钢纤维喷射混凝土的下降速率进一步减小。而
后,采用扫描电子显微镜及压汞法,对损伤后试件微观结构和孔结构进行观察分析,发现随着冻融
循环次数增加，在渗透压和冻胀压力综合作用下,试件内部微裂纹及气孔增多,孔径增大,试件密实
度显著降低;而钢纤维喷射泥凝土中仅出现少量连通毛细孔,这与宏观力学性能变化呈现一致性,
关键词:隧道工程:喷射混凝土;冻融损伤;应力一应变曲线;微观结构
中图分类号：TU502.6;TU528.53
文献标志码:A J
文章编号:1674-4764(2016)01-0030-10
Constitutive relation and microstructure on shotcrete after
freeze and thaw damage
Wang Jiabin , Niu Ditao , Yuan Bin
（School of Civil Engineering , Xi'an University of Architecture and Technology, Xi'an 710055,P. R. China)
Abstract: Using prismatic specimens of concrete, we examined the uniaxial compresston stress strain curve
of ordinary concrete ( mixture C43F10），ordinary shotcrete ( mixture S43F10）and steel fiber reinforced
shotcrete（mixture S43F10SF50）with the same mixture by using the accelerating freeze-thaw method. By
fitting the relationship between parameters and the number of freeze-thaw cycles, the stress-strain curve of
specimens under damaging was calculated. The test results show that with the increase of freezing and
thawing cycles, the peak stress is low and has a liner relation with the freezing and thawing cycles.
However, the peak strain is bigger and demonstrates an exponential relationship. The peak stress of
shotcrete decreases more slowly than that of ordinary concrete, and that of shotcrete with stecl fibe
reduces much more slowly. we also observed and analyzed the microstructure and porcs of specimens alter
damage by using scanning electron microscope and the mercury intrusion method. The result shows tha
收稿日期：2015-11-03
基金项目:国家自然科学基金（51278403）;敏育部刨新团队发展计划（1RT13089);四安建筑科技大学博士研究生例新基
金项目
作者简介:王家演（1986-1.男，博士生，主要从事混凝土结构耐久性研究,（E-mail>lty20020931@163.com。
牛获涛（通信作者）,男，教授，博士生导师，(E-mail)niudidao@163.com。
Received,2015-11-03
University of Ministry of Education of the PRC(No, IRT 13089), the Doctor Innovation Foundation of
Xi'an University of Architecture and Technology
Author brief: Wang Jiabin (1986-) , PhD candidate, main research interest；reinforced concrete structure durability . ( E-
maill) lty20020931@163.com.
Niu Ditao（corresponding author), , professor, doctor supervisor,（E-mail）niudidao@163.com.