高原无砟道床混凝土减缩阻裂措施研究

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摘要 研究目的:为提升高原环境下弹性支承块无砟轨道道床板混凝土的抗裂性能,本文通过干燥收缩试验和中心约束块模拟试验研究内养护剂、聚乙烯纤维、矿物掺合料对高原环境下混凝土抗裂性能的影响,并从变形抑制的角度分析它们的抗裂机理。
研究结论:(1)在高原环境下,掺粉煤灰混凝土试件和掺矿粉混凝土试件分别在3 h和5 d出现裂纹,且裂缝宽度与长度随龄期增加而增加;(2)掺内养护剂和掺聚乙烯纤维混凝土试件在28 d均未出现裂纹,内养护剂和聚乙烯纤维可明显改善高原环境下混凝土的抗裂性;(3)掺内养护剂和掺聚乙烯纤维的混凝土早龄期收缩变形较小甚至出现微膨胀,并且后期收缩也较小;(4)结合自由收缩与约束开裂的试验结果,建议在高原环境下宜控制混凝土7 d自由收缩≤100 με、28 d自由收缩≤400 με,以防止道床混凝土开裂;(5)本研究结论可为高原环境混凝土收缩开裂研究提供参考。

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	何娘者
	李永亮
	曾晓辉
	胡建平
	刘海川
	黄至宪
	李响涛
	李保友
	潘自立
	唐卓
	龙广成

关键词 ：高原地区, 混凝土抗裂, 内养护剂, 聚乙烯纤维, 收缩

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.

Key words： plateau area anti-cracking of concrete internal curing agent polyethylene fiber shrinkage

收稿日期: 2022-07-11

PACS:

TU528

基金资助:国家自然科学基金项目(52078490);中铁二院工程集团有限责任公司科研课题(KYY2019049(19-21))

作者简介: ^**何娘者,1972年出生,男,高级工程师。

引用本文:

何娘者, 李永亮, 曾晓辉, 胡建平, 刘海川, 黄至宪,李响涛, 李保友, 潘自立, 唐卓, 龙广成. 高原无砟道床混凝土减缩阻裂措施研究[J]. 铁道工程学报, 2022, 39(10): 94-99.
HE Niangzhe, LI Yongliang, ZENG Xiaohui, HU Jianping, LIU Haichuan, HUANG Zhixian, LI Xiangtao, LI Baoyou, PAN Zili, TANG Zhuo, LONG Guangcheng. Research on the Measures for Reducing Shrinkage and Anti-cracking of Ballastless Track Bed Concrete in Plateau Area. Journal of Railway Engineering Society, 2022, 39(10): 94-99.

链接本文:

https://tdgcxb.crec.cn/CN/ 或 https://tdgcxb.crec.cn/CN/Y2022/V39/I10/94

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