冶金渣-硫铝酸盐胶凝体系材料加热变化及防火机理

Thermal Performance of Metallurgical Slag and Sulfoaluminate Cement Based Materials and Their Fire Protection Mechanism

中文关键词: 热防护  钙矾石  冶金渣  硫铝酸盐水泥  吸热作用

英文关键词: thermal protection  ettringite  metallurgical slag  sulfoaluminate cement  heat absorption effect

中文摘要:

      目的 为了探寻地下管廊更高防火等级的新要求，利用冶金渣-硫铝酸盐胶凝体系制备富含钙矾石、C-S-H凝胶结合的防火分隔材料。方法 通过高温煅烧试验和热分析，并结合物相分析、微观结构观察、孔隙结构测试等手段，对样品高温行为进行研究。结果 冶金渣胶凝体系中混掺硫铝酸盐胶凝材料，有利于钙矾石的生成，在50~350 ℃的温度区间样品的脱水吸热量从73.27 J/g增加到109.40 J/g以上，样品抗压强度从37.18 MPa提高到40.68 MPa以上。在1 000 ℃下30 min喷烧试验结果显示，10 mm厚度所制备的冶金渣-硫铝酸盐胶凝体系样品的背火面温度为383~336 ℃，且随硫铝酸盐胶凝材料混掺量的增加而降低，其防火性能优于玻镁板和硅钙板防火材料的。结论 该材料热防护机理为含结晶水物相的烧蚀吸热、烧蚀后产生的多孔层的隔热和高温下材料宏观结构完整性的共同作用。

英文摘要:

      The work aims to prepare a kind of fire barrier bonded with C-S-H gel and rich in ettringite content with metallurgical slag and sulfoaluminate cement, in order to meet the higher fire protection demand of underground pipe gallery. The performance of sample at high temperature was investigated via calcination test and thermal analysis combined with means of phase determination, microstructure observation and pore structure examination. Adding sulfoaluminate cement to metallurgical slag system was conducive to the formation of ettringite during hydration. The heat absorption of sample increased from 73.27 J/g to above 109.40 J/g at dehydration temperature range of 50 ℃ to 350 ℃ and the compressive strength also increased from 37.18 MPa to above 40.68 MPa. The results of spray fire testing at 1 000 ℃ for 30 min showed that the backfire temperature of the sample prepared at a thickness of 10 mm lied between 383 ℃ and 336 ℃, which decreased along with the increasing content of sulfoaluminate cement and the sample had superior property in fire protection than the glass fiber - magnesium oxychloride (GFMO) board and calcium silicate autoclaved (CSA) board. The thermal protection mechanism of the sample is due to the combined effect of heat absorption in dehydration of crystallization water-containing phases, thermal insulation of porous layer derived from dehydration, and maintenance of macrostructural integrity for sample at high temperature.