偏高岭土对MAPC基钢结构防火涂料性能的影响

Effect of metakaolin on the performance of ammonium magnesium phosphate cement-based fire retardant coatings for steel structures

为了研究偏高岭土(MK)对磷酸铵镁水泥(MAPC)基钢结构防火性能的影响,测试了其防火性能、正拉粘结强度以及吸水率,并将其与空白样进行对比。结果表明:MK的加入有助于提升MAPC涂层的防火性能,养护28 d后其防火性能相较于M0提升了61 s;MK的微集料效应,使得MAPC涂层的结构更加致密,从而减小MAPC涂层与钢基材粘结界面的缺陷,提升其粘结性能,使其28 d的正拉粘结强度达到0.169 MPa;MK的加入减少开口孔的生成,减小了MAPC涂层的吸水率;掺入MK的MAPC涂层中有磷酸铝类物质生成,新的水化产物包裹在MKP之间,改善MAPC涂层的微观结构。

In order to study the effect of metakaolin(MK)on the fire resistance of ammonium magnesium phosphate cement(MAPC)based steel structures,its fire resistance,positive tensile bonding strength,and water absorption were tested,and compared with the blank sample.The results show that the addition of MK helps to improve the fire resistance of MAPC coating,and after 28 days of curing,its fire resistance is improved by 61 seconds compared to M0.The micro aggregate effect of MK makes the structure of MAPC coating more dense,thereby reducing the defects at the bonding interface between MAPC coating and steel substrate,improving its bonding performance,and achieving a positive tensile bonding strength of 0.169 MPa at 28 days.The addition of MK reduces the generation of open pores and reduces the water absorption of MAPC coatings;Aluminum phosphate substances are generated in the MAPC coating doped with MK,and new hydration products are encapsulated between MKP,improving the microstructure of the MAPC coating.