防火涂料对高强混凝土高温后氯离子渗透性影响

通过5组外包不同厚度防火涂料的C80高强混凝土试块的高温后氯离子渗透试验,研究了氯离子渗透性随涂料厚度的变化情况.试验结果表明:当防火涂料厚度≥30mm时,高温后氯离子渗透性基本不变；当防火涂料厚度为20～25mm时,高温后氯离子渗透性低于常温C50混凝土；当防火涂料厚度为15mm时,高温后氯离子渗透性相对较高.综合考虑后认为,厚度20 mm的防火涂料可同时发挥抑制高强混凝土高温爆裂和降低高温后高强混凝土氯离子渗透性的双重作用.

Influence of Fire Insulation on the Chloride Ion Permeability of High Strength Concrete after High Temperature

Five groups of high strength concrete (HSC) specimens with a 28-day cubic compressive strength of 82.6 MPa and with fire insulation were tested, and the influence of the thickness of fire insulation on the chloride ion permeability of HSC after high temperature was discussed. Test results have shown that, in the case that the fire insulation thickness is 30 mm, the chloride ion permeability of HSC after high temperature is almost the same as that at room temperature; in the case that the fire insulation thickness is 20~25 mm, the chloride ion permeability of HSC after high temperature is still lower than that of C50 concrete at room temperature; and in the case that the fire insulation thickness is 15 mm, the chloride ion permeability of HSC after high temperature is relatively large. It can be concluded that fire insulation with a thickness of 20 mm is effective both for the inhibition of explosive spalling of HSC at elevated temperature and for the reduction of the chloride ion permeability of HSC after high temperature.