This paper presents the results of an experimental study to investigate failure modes of intumescent coatings and their effects on temperatures attained in steel sections and fire resistance of steel columns. Tests were carried out on unloaded steel plates, unloaded short sections and axially loaded long columns. The loaded column specimens had four different surfaces, stainless steel, untreated carbon steel, sand-blasted carbon steel and carbon steel with one layer of fibre cloth. The failure modes of intumescent coating char included cracks, debonding and detachment. Detachment seemed to have occurred after the fire tests because there was no evidence of a sudden jump in temperature. The cracks varied from fine distributed cracks to large discrete cracks. These intumescent coating failure modes affected not only average temperatures of the steel but also temperature distributions in the steel sections. The average temperatures attained in the unloaded steel sections were lower than those in the loaded steel columns. The temperature differences for the unloaded plate and sections were relatively small, lower than 2.2% and 6.3% respectively, while they were high for the loaded test specimens, 10–20% of the average.

本文介绍了一项实验研究的结果，以研究膨胀型涂层的破坏模式及其对钢截面温度和钢柱耐火性的影响。测试是在空载的钢板，空载的短节和轴向加载的长柱上进行的。加载的柱试样具有四个不同的表面，即不锈钢，未经处理的碳钢，喷砂碳钢和带有一层纤维布的碳钢。膨胀型炭的破坏模式包括裂纹，脱粘和剥离。火灾测试后似乎发生了拆离，因为没有证据表明温度突然升高。裂纹从细小的分布裂纹到大的离散裂纹不等。这些膨胀型涂层破坏模式不仅影响钢的平均温度，而且影响钢截面中的温度分布。在卸载的钢段中达到的平均温度低于在加载的钢柱中的平均温度。空板和断面的温差相对较小，分别低于2.2％和6.3％，而空载试样的温差较高，为平均值的10％至20％。