摘要
To understand the effect of steam curing temperature on the hydrate and microstructure of hardened cement paste,several measuring methods including X-ray diffraction(XRD),atomic absorption spectroscopy(ASS),ion chromatography,conductivity meter,alternating-current impedance spectroscopy and nuclear magnetic resonance(NMR)are employed to investigate the hydration characteristics,pore solution composition and conductivity,resistivity and pore structure during the steam curing process.Experimental results show that steam curing promotes the hydration process,greatly raises the resistivity,and decreases the porosity of specimen at early age.Compared with being treated at 45℃,higher temperature leads to a fast decomposition of ettringite at initial stage of the constant temperature treatment period,which improves the relative content and ionic activity of the conductive ions in pore solution.Furthermore,the number of pores larger than 200 nm increases significantly,which reduces the resistivity of the hardened cement paste.Cement paste treated at 45℃ has a more stable and denser microstructure with less damages.
为了解蒸汽养护温度对硬化水泥浆体水化物相及孔隙结构的影响,采用X射线衍射、原子吸收光谱、离子色谱、电导率仪、核磁共振、交流阻抗等方法研究了在蒸汽养护过程中水泥浆体的水化特征、孔溶液组成与导电特性、基体电阻率以及孔隙结构。试验结果表明,蒸汽养护促进了水化过程,大幅度提高了基体早期电阻率并降低了孔隙率。与在45℃养护温度下相比,在恒温养护阶段初期,更高的养护温度导致钙矾石快速分解,从而提高了孔溶液中导电离子的相对含量和离子活度。此外,大于200 nm的孔数量显著增加,降低了硬化水泥浆体的电阻率。45℃养护温度下的水泥浆体微观结构较稳定且致密,产生的内部损伤较小。
作者
XIANG Yu
XIE You-jun
LONG Guang-cheng
HE Fu-qiang
向宇;谢友均;龙广成;何富强(School of Civil Engineering,Central South University,Changsha 410075,China;School of Civil Engineering and Architecture,Xiamen University of Technology,Xiamen 361024,China;Key Laboratory of Green Building Materials(Xiamen University of Technology),Fujian Province University,Xiamen 361024,China)
基金
Projects(U1534207,11790283,51878583)supported by the National Natural Science Foundation of China。