The accelerated aging test on a fire resistive coating (FRO for steel structure was done to understand the effects of temperature and humidity variation on FRC physical properties and durability. In the laboratory aging test, FRC thickness and the cycles of temperature and humidity were controlled, and the phenomena including the surface aspect, color, microstructure and adhesion were observed. Test results indicate that FRC has a tendency in mass loss, thickness decrease, fracturing, darkening and yellowing in color, and pore enlargement after exposure to increase the cycles of temperature and humidity variations. The higher the FRC thickness is, the more obvious these phenomena are. Within the 40 cycles of temperature and humidity conducted, the adhesion between FRC coating and steel is found to be increased at the early cycles but decreased finally at the late cycles. After the exposure to same cycles of temperature and humidity, thinner FRC shows a higher adhesion compared to a thicker one. The final conclusion supported by the accelerated aging test is that a thin FRC possesses a better resistance and durability to weather variation.%进行了钢结构防火涂料室内模拟加速老化试验,探讨了环境温湿度变化对防火涂料的物理着装状态及其耐久性的影响;选择防火涂层厚度和温湿循环次数为变量,试验测定循环前后防火涂层外观、色差、微结构及粘结强度的变化.试验结果表明:随着温湿循环次数的增加,防火涂层发生质量损失、厚度减少、龟裂、颜色变暗泛黄及孔隙扩大现象;防火涂料的初始涂层厚度越大,这种变化趋势越明显;在测试的40次温湿循环范围内,防火涂层与钢板基材之间的附着力有提高的趋势,但随着循环次数的继续增加,附着力开始降低;温湿循环相同时,薄层涂料的附着力大于厚层涂料;与厚层防火涂层相比,薄层涂料物理着装状态受温湿循环次数影响较小,抵抗老化变形的能力较强,耐候性更高.
展开▼
