空腔陶粒混凝土墙板耐火性能研究

Fire performance of hollow-cavity ceramsite concrete wallboard

为了研究空腔陶粒混凝土墙板(hollow-cavity ceramsite concrete wallboard, HCCCW)的耐火性能,对4片HCCCW开展了单面受火试验,得到其热响应、耐火极限和平面外变形,给出了单面受火时HCCCW的传热机理。通过建立有限元模型对截面温度场和温度梯度的分布特征进行了分析。基于已验证的模型,对空腔孔壁面积、体积空腔率、陶粒混凝土密度以及填充材料类型进行参数分析。结果表明:当体积空腔率从23.55%增加至35.00%时,背火面水蒸气逸出持时和受火面上的裂纹数量分别减少43.75%和58.97%;背火面温度-时间曲线中的热峰传递和温度平台阶段的持时随着HCCCW体积空腔率和空腔孔壁面积的减少而增加;与陶粒混凝土热传导相比,HCCCW空腔辐射的传热效率显著更高,相同时刻空腔中心温度约比腹板中点的高20%;减小空腔孔壁面积、体积空腔率和提高陶粒混凝土密度可有效提升HCCCW的耐火性能;综合考虑结构自重、用料成本和耐火性能三方面因素,采用岩棉填充空腔最具有性价比。

To investigate the fire performance of hollow-cavity ceramsite concrete wallboards(HCCCW),this study conducted one-sided fire tests on four HCCCWs.The experiment yielded results on their thermal response,fire resistance,and out-of-plane deformation,providing insights into the heat transfer mechanism of HCCCWs under one-sided fire exposure.An analysis of the distribution characteristics of section temperature fields and temperature gradients was performed by establishing finite element models.Based on the validated models,parametric studies were conducted on hollow-cavity area,volume-cavity ratio,ceramsite concrete density,and type of flling material.The results indicate that as the volume-cavity ratio increases from 23.55%to 35.00%,the duration of steam escape from the unexposed surface decreases by 43.75%and the number of cracks on the fire-exposed surface decreases by 58.97%.In the temperature-time curve for the unexposed surface of HCCCW,both the duration of heat front propagation and the temperature plateau increase with the decrease in volumetric cavity ratio and cavity wall area.Compared with heat conduction in ceramsite concrete,cavity radiation significantly improves heat transfer efficiency.Additionally,the temperature at the center of the cavity is approximately 20%higher than that at its midpoint along with webbing.Decreasing hollow-cavity area and volume-cavity ratio or increasing ceramsite concrete density effectively enhances the fire performance of HCCCW.Considering structural weight,material cost and fire resistance,filling cavities with rockwool is proven to be most cost-effective.