硅烷-纳米SiO_(2)复合表面改性钢纤维超高性能混凝土参数优化及其力学性能  

Optimization of parameters and mechanical properties of silane-nano SiO_(2)composite surface modified steel fiber reinforced ultra-high performance concrete

作　　者：田杰夫 杨贞军 杨国君 姚勇 TIAN Jiefu;YANG Zhenjun;YANG Guojun;YAO Yong(Key Laboratory of Geotechnical and Structural Engineering Safety in Hubei Province,School of Civil Engineering,Wuhan University,Wuhan 430000,China;College of Civil Engineering and Architecture,Zhejiang University,Hangzhou 310058,China)

机构地区：[1]武汉大学土木建筑工程学院,岩土与结构工程安全湖北省重点实验室,武汉430000 [2]浙江大学建筑工程学院,杭州310058

出　　处：《复合材料学报》2025年第3期1479-1488,共10页Acta Materiae Compositae Sinica

基　　金：国家自然科学基金(52173300)。

摘　　要：为提升钢纤维增强超高性能混凝土(UHPFRC)的力学性能,提出一种采用氨基丙基三乙氧基硅烷(KH550)和纳米SiO_(2)(Nano-SiO_(2))对钢纤维表面进行复合改性的新工艺。考虑乙醇和水的质量比(We∶Wd)、KH550含量(wt%)、Nano-SiO_(2)含量(wt%)和水浴温度(Twb)共4个参数对配比进行正交设计(L9(34))。首先筛选溶液稳定性较好的4种配比对纤维表面进行改性,然后使用FTIR和SEM分析涂层成分和形貌,最后根据UHPFRC试件28 d的抗弯和抗压强度给出最优改性工艺参数。结果表明:(1)最优改性工艺参数为:We∶W_(d)=3,KH550=10wt%,Nano-SiO_(2)=0.5wt%和T_(wb)=80℃,其中We∶Wd是影响溶液稳定性的主要因素;(2)FTIR显示存在Fe−O−Si特征峰,表明KH550和Nano-SiO_(2)成功键合于钢纤维表面;(3)SEM显示最优改性工艺下涂层分布均匀,未见纳米SiO_(2)颗粒明显团聚;(4)掺入最优改性工艺处理后高强纤维的UHPFRC试件在1vol%、1.5vol%和2vol%纤维体积分数下的抗弯强度(28、30.5和37MPa)比未改性试件分别提升40.4%、28.5%和32.7%,抗压强度(133.3、151.7和163.9MPa)分别提升7.5%、8.3%和13%;(5)复合改性使1.5vol%和2vol%纤维体积分数下的试件跨中裂缝形态曲折复杂,显著增强了纤维-基体界面性能。To improve the mechanical properties of steel fiber reinforced ultra-high performance concrete(UHPFRC),a new composite modification method of steel fiber surfaces was proposed using silane coupling agent KH550 and nano-SiO_(2)particles.Four parameters,including the mass ratio of ethanol to water(We∶Wd),the content of KH550(wt%),the content of nano-SiO_(2)(wt%),and the water bath temperature(Twb),were considered for the orthogonal design of proportions(L_(9)(3^(4))).Firstly,four mixtures with good solution stability were selected for fiber surface modification.The FTIR and SEM were then used to analyze the composition and morphology of the coatings.Finally,the optimal modification process parameters were determined based on the bending and compressive strength of UHPFRC specimens at 28 d.The results show that:(1)The ratio of We∶Wd is the main factor affecting the stability of the solution,and the optimal modification parameters are:We∶W_(d)=3,KH550=10wt%,Nano-SiO_(2)=0.5wt%,and Twb=80℃;(2)The FTIR results exhibit characteristic peaks of Fe−O−Si,indicating successful bonding of KH550 and Nano-SiO_(2)on the steel fiber surfaces;(3)The SEM results indicate uniform distributions of composite coatings without aggregation of Nano-SiO_(2)particles on the fiber surfaces modified by the optimal parameters;(4)For the fiber volume fractions of 1vol%,1.5vol%,and 2vol%,the bending strength(28,30.5,37 MPa)and compressive strength(133.3,151.7,163.9 MPa)of UHPFRC specimens with optimally-modified fibers are increased by 40.4%,28.5%,32.7%,and 7.5%,8.3%,13%,respectively,compared to the specimens with untreated fibers;(5)The composite modification technique significantly improves the fiber-matrix interfaces,as demonstrated by more tortuous and complex crack morphologies in the specimens with fiber volume fractions of 1.5vol%and 2vol%.

关 键 词：硅烷偶联剂 纳米二氧化硅 钢纤维改性 超高性能混凝土 力学性能 

分 类 号：TB333[一般工业技术—材料科学与工程]