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中南大学学报(自然科学版)

Journal of Central South University

第49卷    第10期    总第290期    2018年10月

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文章编号:1672-7207(2018)10-2568-08
岩溶地基改性注浆材料力学性能及其孔隙结构特征
宋国壮1,王连俊1,张艳荣1,郭颖1,曹元平2

(1. 北京交通大学 土木建筑工程学院,轨道工程北京市重点实验室,北京,100442;
2. 中铁第一勘察设计院集团有限公司,陕西 西安,710000
)

摘 要: 为了制备高速铁路岩溶地基加固工程及高性能水泥基材料,研制一种改性高聚物即水泥基(HPC)注浆材料,对其与常规水泥浆液(Blank)、水泥-水玻璃(C-S)的力学性能及体积稳定性等进行室内试验对比分析;运用压汞测试技术(MIP)探究其硬化后浆体微观组构与宏观力学性能间的本质关联性。研究结果表明:在28 d龄期下,Blank,C-S和HPC试件单轴抗压强度与龄期为7 d的相比分别增大77%,20%和78%,体积损失率分别为18.3%,4.9%和1.2%;聚合物体系的协调效应减小了传统水泥基注浆材料体积失稳及因单掺速凝剂导致后期强度发展缓慢的缺陷;复合掺用多高聚物显著降低了硬化水泥浆体内部孔隙直径即孔径,使孔径分布趋于细化;在28 d龄期下,不同体系的HPC浆体抗压强度与材料内部孔隙率、阈值孔径均呈指数关系,与平均孔径呈线性负相关,揭示其孔隙结构分布特征可有效反映HPC浆体力学性能的变化规律,降低孔径有利于提升其力学性能。

 

关键字: 高聚物;抗压强度;体积收缩;孔隙结构;孔径分布

Mechanical stability and pore structures of modified grouting material in karst foundation
SONG Guozhuang1, WANG Lianjun1, ZHANG Yanrong1, GUO Ying1, CAO Yuanping2

1. Beijing Key Laboratory of Track Engineering, School of Civil Engineering, Beijing Jiaotong University, Beijing 100442, China;
2. China Railway First Survey and Design Institute Group Ltd., Xi’an 710000, China

Abstract:A modified high polymers cement-based(HPC) grouting material was developed and the differences between that and conventional cement paste(Blank), cement-silicate(C-S) on mechanical properties and dimension stability were analyzed to consolid foundation on high speed railway and prepare materials with high performance cementitious materials. The relationship between microstructure and macroscopic mechanical properties of HPC was investigated using mercury penetration(MIP). The results show that the compressive strength of Blank, C-S and HPC specimen at 28 d increase by 77%, 20% and 78%, respectively, compared with those at 7 d, and the dimension losses are 18.3%, 4.9% and 1.2%, respectively, which indicates that the dimension stability and mechanical property at late stage of traditional cementitious grouting material can be improved by the synergy effect of polymers system. The pore size of hardening cement paste reduces obviously and the pore radius distribution tends to thin with multiple high polymers. There presents exponential relationship is presented between internal porosity, threshold pore diameter and the compressive strength of different HPC pastes at 28 d, which has negative linear correlation with average pore diameter. The above mentioned solutions reveal that the mechanical properties of HPC can be reflected by the distribution characteristics of pore structure, and which can be improved by decreasing the pore radius.

 

Key words: high polymer; compressive strength; dimension shrinkage; pore structure; pore size distribution

中南大学学报(自然科学版)
  ISSN 1672-7207
CN 43-1426/N
ZDXZAC
中南大学学报(英文版)
  ISSN 2095-2899
CN 43-1516/TB
JCSTFT
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