摘要
为揭示高地温干热环境下纤维对喷射用混凝土的改善机理,设计了基准工况、玻璃纤维工况、微丝镀铜钢纤维工况及端钩型钢纤维工况,通过力学性能试验及压汞法测试技术研究了混凝土力学性能及微观孔隙特征,并建立了强度与孔隙结构参数的数学模型.结果表明:干热环境下,掺加纤维材料后,混凝土力学性能得到不同程度的提高,其中端钩型钢纤维工况改善效果最好,与基准工况相比,1、7、28 d龄期的抗压强度分别提高了28.47%、64.40%和74.78%,劈裂抗拉强度分别提高了88.5%、72.6%和110.6%;掺加纤维材料可有效减少混凝土有害孔孔径,28 d龄期时掺加纤维工况的最可几孔径约为62.5 nm,而基准工况约为110 nm;综合考虑分形维数及复合孔隙率的多因素关系强度模型可准确描述强度与孔隙结构参数的定量关系.
To reveal the improvement mechanism of fiber on shotcrete for spraying in the hot-dry environment at high ground temperature,the basic mix proportion condition,the glass fiber condition,the copper plating microfilament steel fiber condition and the hooked end steel fiber condition were designed.Mechanical property and microscopic pore characteristics of concrete were studied by mechanical property tests and the mercury injection method.The mathematical models of the strength and the pore structure parameters were established.The results show that in the hot-dry environment,the mechanical properties of concrete can be improved after adding fiber materials,and the hooked end steel fiber condition has the best improvement effect.Compared with the basic mix proportion condition,the compressive strengths with the age of 1,7,28 d increase by 28.47%,64.40%and 74.78%,respectively,and the splitting tensile strengths increase by 88.5%,72.6%and 110.6%,respectively.The addition of fiber materials can effectively reduce the porosity of harmful pores of concrete.The most probable aperture of the fiber addition with the age of 28 d is about 62.5 nm,while the basic mix proportion condition is about 110 nm.The multi-factor strength mathematical model that comprehensively considers the influence of fractal dimension and composite porosity can accurately describe the quantitative relationship between strength and pore structure parameters.
作者
崔圣爱
符飞
曾光
陈振
李固华
Cui Shengai;Fu Fei;Zeng Guang;Chen Zhen;Li Guhua(School of Civil Engineering, Southwest Jiaotong University, Chengdu 610031, China)
出处
《东南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2022年第1期43-49,共7页
Journal of Southeast University：Natural Science Edition
基金
国家自然科学基金面上资助项目(51678492).
关键词
高地温干热环境
纤维混凝土
力学性能
孔隙结构
分形模型
high-temperature hot-dry environment
fiber concrete
mechanical property
pore structure
fractal model
