Abstract：Research purposes：In the existing concrete frost resistance test, the rapid freeze-thaw test is often adopted, with long test cycle and high cost. On consideration to that the pore structure could stably exist in hardened concrete, the research was done on determining the relation between test age and concrete pore to reduce the test cycle of frost resistance.
Research conclusions：The hardened air content of C30 concrete increases gradually with the increase of age, while there are not obvious rules between pore structure and age ofC50 concrete. The air-entraining ggent of poor quality will introduce the large amount of large-diameter bubbles to decrease the compressive strength of concrete. As the C50 Concrete is of much viscosity, the more AEA is needed, generating smaller bubbles than C30 Concrete. The test sample preparation is an important step in the process of bubble structure test. The strength of the sample will affect the measured results. To ensure accurate test results, the test age of C30 concrete is not be earlier than 28 days, while the steam curing of C50 concrete is notbe earlier than 7days. In the premise of ensuring the frost resistance of concrete, the bubble spacing coefficient of different concrete is quite different, and the bubble spacing coefficient of C30 concrete is larger than C50 concrete.
Jia Yaodong, Xie Yongjiang, Zhu Changhua. Requirement and Test Method of Concrete Frost Resistance in Various Countries[J]. Concrete, 2005(6): 24-28.
[ 4 ] Ley M T, Chancey R, Juenge M C G, Folliard K J. The physical and chemical characteristics of the shell of air-entrained bubbles in cement paste[J]. Cement and Concrete Research, 2009(39): 417-425.
[ 5 ] Foy C, PigeonM, Banthia N. Freeze -thaw durability and deicer salt scaling resistance of a 0.25 water-cement ratio concrete[J]. Cement and Concrete Research, 1988(4): 604-614.
[ 6 ] Pigeon M, Marchand J, Pleau R. Frost resistant concrete[J]. Construction and Building Materials, 1996(5): 339-348.
Zhang Desi, Cheng Xiuzhen. Research on the Freeze/ Thaw Durability of PFA Concrete[J]. Journal of Northwestern Polytechnical University, 2000(2): 175-178.
Yang Qianrong, Zhang Shuqing, Yang Quanbing, et al. Effects of Air-entraining Agent on Air Void Parameters of Concrete[J]. Journal of Tongji University(Natural Science). 2008(3): 374-378.
Hu Jiang, Huang Jiamu, LiHuajian, et al. Study on Freezing-thawing Resistance and Air Characteristics of Concrete with Mineral Admixtures[J]. Railway Engineering, 2009(6): 124-127.
Yang Qianrong, Zhu Beirong, Yang Quanbing, et al. Effects of High-frequency Vibration on Air Void Parameters of Air-entrained Concrete[J]. Journal of Building Materials, 2007(3): 331-336.
[ 12 ] Jakobsen U H, Pade C, Thaulow N , Brown D, Sahu S, M agnusson O, Buck S D, Schutter G D. Automated air void analysis of hardened concrete-a Round Rob in study[J]. Cement and Concrete Research, 36 (2006),1444-1452.
[ 13 ] T.C. Powers, Properties of Fresh Concrete, John Wiley & Sons, Inc., New York, 1968.
Lv Lihua, Guo Xiaoguang, Guan Xikun, et al. Effect of Age on Assessing the Frost Resistance of Concrete with Bubble Spacing Method[C]//The Collections of 7th National Conference on Concrete Durability. Yichang, 2008: 272-277.
Zhang Yuhai, Wang Xiufen. Research on Concrete Freeze-thawing Test for the Second Line from Tibet to Golmud of Qinghai-Tibet Railway[J]. Journal of Railway Engineering Society, 2007(11): 39-43.
2010, Vol. 27 
版权所有 © 2014 《铁道工程学报》编辑部