摘要
以成绵乐高铁无砟轨道混凝土出现泛碱病害为工程背景,针对C60混凝土泛碱及相关力学问题,采用“半浸泡法”模拟泛碱多潮环境,证实了纳米二氧化硅百分含量低于3%时,对泛碱有明显抑制作用,单方面对于抑制其泛碱而言,纳米二氧化硅的最佳掺量值大于4%,但此后其泛碱抑制能力增益的速率随其掺量增加而减小。通过本文设计的“病害放大法”,对Y1组添加过量氢氧化钙(外加5%),致使其严重泛碱时,其抗压强度相对基准对照组下降了3.9%,验证了严重泛碱对C60混凝土的抗压强度具有负面影响。利用纳米二氧化硅、粉煤灰、减水剂三者的耦合效应,减小了纳米二氧化硅的团聚效应对混凝土后期强度的影响,纳米二氧化硅掺量值为3%以内时,对C60混凝土的抗压强度和抗折强度有积极贡献意义;纳米二氧化硅掺量值大于3%时,力学强度已低于标准值。综合考虑泛碱抑制和力学性能的提高,C60混凝土的纳米二氧化硅最佳掺量范围宜在3%以内。
The research this paper is based on the efflorescence damage of concrete of ballastless track of Chengdu-Mianyang-Leshan High-speed Railway. This paper is committed to inhibiting the efflorescence damage of C60 concrete and improving its mechanical properties as well. The “semi immersion method” is used to simulate the multi tidal environment of efflorescence. It is confirmed that when the percentage content of nano silica is less than 3%, the inhibitory effect on efflorescence is obvious. The optimal content of nano silica for the inhibition of its efflorescence is greater than 4%, but the rate of gain of its efflorescence inhibition ability decreases with the increase of its content. Through the innovative “damage amplification method” in this paper, the compressive strength of Y1 group is decreased by 3.9% compared with that of the benchmark control group with added excessive calcium hydroxide(plus 5%), which verifies that serious efflorescence has a negative impact on the strength of C60 concrete. The coupling effect of nano silica, fly ash and superplasticizer is used to reduce the influence of nano silica agglomeration effect on the later strength of concrete. When the content of nano silica is less than 3%, it has a positive contribution to the compressive strength and flexural strength of C60 concrete. When the content of nano silica is greater than 3%, the mechanical strength is lower than the standard value. Considering the inhibition of efflorescence and the improvement of mechanical properties, the optimal content range of nano silica in C60 concrete should be less than 3%.
作者
熊镇疆
刘梦辉
陈嵘
李福海
余弦
张清绪
XIONG Zhenjiang;LIU Menghui;CHEN Rong;LI Fuhai;YU Xuan;ZHANG Qingxu(School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China;Sichuan Energy Construction Engineering Group Co.,Ltd.,Chengdu 610021,China)
出处
《铁道标准设计》
北大核心
2023年第1期127-133,共7页
Railway Standard Design
基金
四川省科技厅中央引导地方科技发展专项(2020ZYD011)
四川省科技计划项目(2021YJ0545)
四川省交通运输科技项目(2021-B-01)。
关键词
板式无砟轨道
泛碱抑制
力学性能
纳米二氧化硅
外加剂耦合效应
半浸泡法
病害放大法
ballastless slab track
efflorescence inhibition
mechanical properties
nano silica
admixture coupling effect
semi immersion method
damage amplification method
作者简介
熊镇疆(1997-),男,硕士研究生,主要从事板式无砟轨道混凝土研究,E-mail:657398956@qq.com;通信作者:余弦(1991-),女,高级工程师,2015年毕业于西南交通大学,工学硕士,主要从事工程技术研究工作,E-mail:86283477@qq.com。
