多孔壳微胶囊对硬化砂浆抗渗性的影响  

Influences of silica porous shell microcapsules on the impermeability of hardened cement mortar

作　　者：张力冉 邢锋[1] 王芳 董必钦[2] 孔祥明 ZHANG Liran;XING Feng;WANG Fang;DONG Biqin;KONG Xiangming(Guangdong Key Laboratory of Durability in Coastal Civil Engineering,College of Civil Engineering,Shenzhen University,Shenzhen 518060,China;Department of Civil Engineering,Tsinghua University,Beijing 100084,China)

机构地区：[1]深圳大学土木工程学院广东省滨海土木工程耐久性重点实验室,深圳518060 [2]清华大学土木工程系,北京100084

出　　处：《复合材料学报》2019年第4期982-992,共11页Acta Materiae Compositae Sinica

基　　金：国家自然科学基金(U1301241)

摘　　要：采用原位聚合与水解缩聚法,以四乙氧基硅烷(TEOS)、环氧树脂(E51)、苯乙烯(St)等为主要原料,合成了一种二氧化硅多孔壳微胶囊(Porous silica shell microcapsules,PSSM)。分别采用SEM、FTIR、TGA对PSSM外观形貌、化学组分、核壳比进行表征。通过对掺加PSSM的砂浆试块进行80%抗压强度荷载预压、养护(浸水或干湿循环养护)处理后,运用交流阻抗法与压汞法研究了PSSM对硬化砂浆抗渗性与孔结构的影响规律。结果表明:制备的PSSM粒径约为10～100μm,其含有聚苯乙烯网络支架、环氧树脂和聚硅氧烷囊芯,支架聚合物和多孔壳,核壳质量比为1.54。与未预压-养护处理的试块相比,经预压-养护处理后的空白试块的连通孔溶液电阻RCH和扩散阻抗系数σ均降低,孔隙率升高,表明预压使试块内形成微裂纹缺陷,经养护仍未愈合,因此试块抗渗性降低;而对于掺加8%PSSM的试块,经预压-养护处理后其RCH和σ均增加,孔隙率降低,表明试块抗渗性提高。这是由于PSSM的破壳-固化作用以及长期浸水或干湿循环养护,导致试块中PSSM发生了渗出-固化作用,封堵愈合了试块内的微裂隙,抗渗性得到提高。By using tetraethyl orthosilicate(TEOS),epoxide resin(E51),styrene(St),et al.as the main materials,a kind of porous silica shell microcapsules(PSSM)were synthesized through in-polymerization in the core and hydrolysis-polycondensation for forming the shell.Scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FTIR)and thermogravimetric analysis(TGA)were used to characterize the morphology,chemical composition and core shell ratio of the synthesized PSSM.Influences of PSSM on the impermeability and pore structure of hardened cement mortar via alternating current impedance spectroscopy technique(ACI)and mercury intrusion porosimetry(MIP)were studied after the hardened cement mortar samples were preloaded by 80% their compressive strength loads and cured including water curing or dry-wet cycling curing.The characterization results prove that the obtained product presents core-shell structured microcapsules with size of 10-100 μm,in which poly-siloxane forms porous shell and liquid form epoxy resin held by a polystyrene network composes the core.The mass ratio of the core to shell is 1.54.Compare with the blank samples without preloading-curing treatment,connected pore solution resistance RCH and diffusion resistance coefficient σ of the preloading-curing treated blank samples decrease and their porosities increase,which suggests that the preloading treatment leads to the formation of micro-cracks in the specimen and the following curing does not result in full healing of the formed micro-cracks.On the other hand,for those sample containing 8% PSSM,RCH and σ of the preloading-curing treated samples are even higher than those of the non-treated samples.This phenomenon is attributed to the micro-cracks formation due to the preloading treatment allows invasion of water into the body of the mortar specimens during the following water immersion.Thus,the PSSM that is incorporated into the mortar samples contributes to crack healing by leakage of the epoxy resin from the core through the intact or bro

关 键 词：PSSM 交流阻抗法 孔结构 自修复 抗渗性 

分 类 号：TU528.0[建筑科学—建筑技术科学]