基于分形理论的清水镜面混凝土泌水色斑成因研究  

Research on the Causes of Water-secreting Stains of Fair-faced Mirror Concrete Based on Fractal Theory

作　　者：王开凤[1,2] 史文琰 雍占 叶科 朱云升 WANG Kai-feng;SHI Wen-yan;YONG Zhan;YE Ke;ZHU Yun-sheng(School of Transportation and Logistics Engineering,Wuhan University of Technology,Wuhan 430063,China;Hubei Highway Engineering Technology Center,Wuhan 430063,China;Sichuan Transportation Construction Group Co,Ltd,Chengdu 610047,China)

机构地区：[1]武汉理工大学交通与物流工程学院,武汉430063 [2]湖北省公路工程技术中心,武汉430063 [3]四川省交通建设集团有限责任公司,成都610047

出　　处：《武汉理工大学学报》2023年第3期88-94,共7页Journal of Wuhan University of Technology

摘　　要：针对预制箱梁清水镜面混凝土表面出现的泌水色斑外观质量缺陷,通过XRD、SEM从微观层面分析水化产物差异确定其成因,并利用分形理论分析混凝土中含气量和骨料级配对泌水色斑的影响规律,最后总结得到泌水色斑形成机理。结果表明,泌水色斑主要是由于局部水胶比偏大,导致水化产物Ca(OH)_(2)、CaCO_(3)减少了4.9%,从而形成相比良好外观处更加疏松、多孔的微观结构表面。混凝土原材料分形维数与泌水色斑面积成负相关,高含气量和低细度模数对应的物相分形维数更大,其所占气相和固相部分在混凝土中空间分布更为复杂,对泌水通道的形成造成更大空间阻力。在含气量和细集料允许区间内,消泡剂掺量2.5‰、细度模数2.2的细骨料在空间结构中具有最大分形维数,能最大程度减少泌水色斑的形成。Aiming at the appearance quality defects of water-secreting stains on the surface of prefabricated box girder fair-water mirrored concrete,XRD and SEM were used to analyze the differences of hydration products from the microscopic level to determine their causes,and the influence of gas content and aggregate grade paired water-secreting stains in concrete was analyzed.Finally the formation mechanism of water-secreting stains was summarized.The results show that the water-secreting stains is mainly due to the large local water-to-adhesive ratio,resulting in a 4.9% reduction of the hydration products Ca(OH)_(2) and CaCO_(3),thus forming a looser and porous microstructural surface than the good appearance.The fractal dimension of concrete raw materials is negatively correlated with the area of water-secreting stains,and the fractal dimension corresponding to high gas content and low fineness modulus is larger,and the spatial distribution of gas phase and solid phase parts is more complex in concrete,which causes greater spatial resistance to the formation of water channel.In the allowable interval of gas content and fine aggregate,the fine aggregate with defoamer content of 2.5%o and fineness modulus of 2.2 has the largest fractal dimension in the spatial structure,which can minimize the formation of water-secreting stains.

关 键 词：清水镜面混凝土 泌水色斑 分形维数 水化产物 

分 类 号：TU528[建筑科学—建筑技术科学]