聚丙烯纤维混凝土高温后的孔隙结构特征研究

发布时间：2018-04-01 02:16

本文选题：混凝土　切入点：聚丙烯纤维　出处：《华中科技大学学报(自然科学版)》2014年04期

【摘要】：以吸附-凝聚理论为基础,采用氮吸附法研究聚丙烯纤维混凝土在不同温度下的孔隙结构特征.通过分析试样的吸附-脱附等温曲线特征、孔径分布、比表面积,探讨了高温作用以及聚丙烯纤维对混凝土孔隙结构的影响.试验结果表明:经历不同温度的混凝土,其硬化水泥砂浆试样中均存在两端开口的孔隙,且温度越高开口孔隙的孔径越大,连通性更强.经历高温后,混凝土孔隙结构发生了改变,孔径大于200nm的孔隙数量显著增多,孔径小于50nm的孔隙相应减少,最可几孔径显著增大.经历高温前,聚丙烯纤维混凝土试样的比表面积均小于普通混凝土,最可几孔径则差别不大.与普通混凝土相比,聚丙烯纤维混凝土中小孔分布较少,而孔径较大的孔分布更多.经历高温后,纤维混凝土试样的孔径分布规律和比表面积与普通混凝土接近.
[Abstract]:Based on the theory of adsorption-condensation, the pore structure characteristics of polypropylene fiber concrete at different temperatures were studied by nitrogen adsorption method.The characteristics of the isotherm curve, pore size distribution and specific surface area of the sample were analyzed. The effects of high temperature and polypropylene fiber on the pore structure of concrete were discussed.The experimental results show that there are pores at both ends of hardened cement mortar samples with different temperatures, and the higher the temperature, the larger the pore size and the stronger the connectivity.After high temperature, the pore structure of concrete has been changed, the number of pore size larger than 200nm has increased significantly, the pore size smaller than 50nm has decreased, and the most probable pore size has increased significantly.Before high temperature, the specific surface area of polypropylene fiber reinforced concrete samples is smaller than that of ordinary concrete.Compared with ordinary concrete, the pore distribution of polypropylene fiber reinforced concrete is less, but that of larger pore diameter is more.After high temperature, the pore size distribution and specific surface area of fiber reinforced concrete samples are close to those of ordinary concrete.
【作者单位】：郑州大学土木工程学院;郑州大学新型建材与结构研究中心;
【基金】：国家自然科学基金资助项目(51178434) 河南省博士后科研资助项目(2012010) 河南省教育厅科学技术研究重点项目(14A560009)
【分类号】：TU528

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