Effect of nano-titanium dioxide on mechanical and electrical properties and microstructure of reactive powder concrete
Effect of nano-titanium dioxide on mechanical and electrical properties and microstructure of reactive powder concrete
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DOI：
10.1088/2053-1591/aa87db
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发表时间：
2017-09
影响因子：
2.3
通讯作者：
Z. Li;B. Han;Xun Yu;Sufen Dong;Liqing Zhang;Xufeng Dong;J. Ou
中科院分区：
文献类型：
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作者：
Z. Li;B. Han;Xun Yu;Sufen Dong;Liqing Zhang;Xufeng Dong;J. Ou
本研究将纳米二氧化钛（NT）引入活性粉末混凝土（RPC）中制备NT增强RPC（NTRRPC）。研究了NTRRPC的机械、电性能和微观结构。研究结果表明，NT由于其成核作用，可以加速RPC早期的水化。养护龄期为28 d时，水泥水化度不含NT掺入。然而，X射线粉末衍射（XRD）分析和扫描电子显微镜（SEM）观察证实，NT的成核效应不仅可以降低氢氧化钙（CH）的取向度，而且可以限制CH的尺寸。因此，NT也可能有助于增强晚年的力量。 28 d龄期时NTRRPC的弯曲和压缩强度相对于对照RPC分别增加了47.07%（相对增加率）/3.62 MPa（绝对增加）和18.05%/18.42 MPa。压实度模型表明NT可以提高RPC的压实度，并将RPC的孔隙率从9.04%降低到6.96%。 SEM观察表明NT可以通过其填充作用细化RPC的孔隙和微裂纹，这与压实度模型的结果一致。另外，NT的添加可以改善RPC的导电性能，使RPC的电阻率降低13.61%。
Nano-titanium dioxide (NT) was introduced into reactive powder concrete (RPC) to prepare NT reinforced RPC (NTRRPC) in this study. The mechanical and electrical properties and microstructure of NTRRPC were investigated. Research results indicate that NT can accelerate the hydration of RPC at early ages due to its nucleation effect. Cement hydration degree is free from the inclusion of NT at the curing age of 28 d. However, x-ray powder diffraction (XRD) analysis and scanning electron microscope (SEM) observation confirm that the nucleation effect of NT not only can reduce the orientation degree of calcium hydroxide (CH), but also can restrict the size of CH. Hence, NT may also benefit to enhance the strength at late age. The flexural and compressive strengths of NTRRPC at age of 28 d achieve increases of 47.07% (relative increase rate)/3.62 MPa (the absolute increase) and 18.05%/18.42 MPa with respect to the control RPC, respectively. The compactedness model demonstrates that NT can improve the compactedness of RPC and reduce the porosity of RPC from 9.04% to 6.96%. SEM observations suggest that the NT can refine the pores and micro cracks of the RPC by its filling effect, which is in accordance with the result of compactedness model. In addition, the addition of NT can improve the electrically conductivity property of RPC and make a 13.61% decrease in the electrical resistivity of RPC.