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| Research on the Measures for Reducing Shrinkage and Anti-cracking of Ballastless Track Bed Concrete in Plateau Area |
| HE Niangzhe1, LI Yongliang2, ZENG Xiaohui3, HU Jianping1, LIU Haichuan3, HUANG Zhixian3, LI Xiangtao4, LI Baoyou1, PAN Zili1, TANG Zhuo3, LONG Guangcheng3 |
1. China Railway Eryuan Engineering Group Co. Ltd, Chengdu, Sichuan 610031, China;
2. Tibet Railway Construction Co. Ltd, Linzhi, Tibet 860000, China;
3. Central South University, Changsha, Hunan 410075, China;
4. China Academy of Railway Sciences Corporation Limited, Beijing 100089, China |
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Abstract Research purposes:In order to explore the anti-cracking performance of ballastless track slab concrete with elastic bearing block in plateau environment, the effects of internal curing agent, polyethylene fiber and mineral admixtures on the anti-cracking performance of concrete in plateau environment were studied through drying shrinkage test and central restraint block simulation test, and their anti-cracking mechanism was analyzed from the perspective of deformation inhibition.
Research conclusions:(1) In plateau environment, cracks appear in concrete specimens with fly ash and concrete specimens with mineral powder in 3 hours and 5 days, respectively, and the crack width and length increase with age. (2) The concrete specimens mixed with internal curing agent and polyethylene fiber have no cracks in 28 days; the internal curing agent and polyethylene fiber can significantly improve the crack resistance of concrete in plateau environment. (3) The shrinkage deformation of concrete mixed with curing agent and polyethylene fiber is small at early age, even slightly expanded, and the later shrinkage is also small. (4) Combined with the test results of free shrinkage and restrained cracking, in order to prevent concrete cracking in plateau environment, it is suggested that the 7 days free shrinkage of concrete should ≤100 με and 28 days free shrinkage ≤ 400 με. (5) The research conclusion can provide reference for the study of shrinkage cracking of concrete in plateau environment.
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Received: 11 July 2022
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2022, Vol. 39 
