清水混凝土用Ⅰ级低钙粉煤灰中浮黑物质分析  

Analysis of black particles originated from grade I class fly ash used in fair-faced concrete

作　　者：姜骞 王强[2] 于诚 徐文[3] JIANG Qian;WANG Qiang;YU Cheng;XU Wen(Jiangsu Sobute New Materials Co.Ltd.,State Key Laboratory of High Performance Civil Engineering Materials,Nanjing 211103,China;Jiangsu Provincial Transportation Engineering Construction Bureau,Nanjing 210004,China;Jiangsu Research Institute of Building Science Co.Ltd.,Nanjing 210008,China)

机构地区：[1]江苏苏博特新材料股份有限公司高性能土木工程材料国家重点实验室,江苏南京211103 [2]江苏省交通工程建设局,江苏南京210004 [3]江苏省建筑科学研究院有限公司,江苏南京210008

出　　处：《新型建筑材料》2022年第4期52-55,93,共5页New Building Materials

基　　金：国家重点研发计划项目(2021YFB1600300)。

摘　　要：粉煤灰浮黑现象极易造成清水混凝土外观色差,通过宏观和微观测试方法对比分析了Ⅰ级低钙粉煤灰及其浮黑物质的物理化学性质。结果表明:粉煤灰中浮黑物质的主要组成元素为Al、Si和O,与粉煤灰相比其主要组成晶相中莫来石更多、石英较少,浮黑物质的颗粒尺寸(中位粒径D_(50)=85μm)明显大于粉煤灰(中位粒径D_(50)=13μm);浮黑物质的组成与热性质均表明其并非粉煤灰中未燃尽碳,利用烧失量指标不能准确评价浮黑物质含量。Floating upward phenomena of black particles originated from fly ash led to severe color difference on fair-faced concrete. Physical and chemical properties of black particles and Grade Ⅰ Class fly ash were tested and analyzed based on macroscopic and microscopic test methods. The results showed that,the main composing element of black particles were Al,Si and O. Comparing the main crystal compositions with fly ash,more mullite and less quartz were found in black particles. Moreover,much bigger particle size of black particles(half-content diameter D_(50)=85 μm) was observed,while D_(50)of fly ash was 13 μm. The test results of composition and thermal property indicated that the black particles were not unburned carbon as they were assumed in the past. Therefore,index of loss on ignition was not able to reflect content of black particles in fly ash.

关 键 词：级低钙粉煤灰 浮黑物质 物理化学性质 清水混凝土 色差 

分 类 号：TU528.041[建筑科学—建筑技术科学]