抑制高强混凝土受火爆裂的措施

提出了定量表征混凝土受火爆裂程度的方法，研究了4种纤维、1种聚合物乳液和2种防火涂层对硅灰和粉煤灰高强混凝土受火爆裂的抑制效果。研究表明：单丝状、直径较小的聚丙烯纤维可有效抑制爆裂。提出了包裹于纤维表面的混凝土柱的直径计算方法，并定量描述纤维掺量和直径对抗爆裂的影响。孔结构分析表明：添加物能有效抑制爆裂的一般表现为混凝土试件受火后孔隙率显提高，最可几孔径发生明显偏移，并且此最可几孔占有一定的数量。防火涂层抗爆裂具有一定的效果，抗爆裂效果与涂层本身性能有关。

MEASURES FOR IMPROVING SPALLING RESISTANCE OF HIGH STRENGTH CONCRETE EXPOSED TO FIRE

A quantitatively characterization method to the spalling degree of concrete exposed to fire was proposed. The spalling suppressing effects of high strength concrete with silica fume and fly ash were investigated by blending with four fibers, one polymer latex and two coatings. The research results show that the monofilament polypropylene fiber with a smaller diameter has a better effect for inhibiting the spalling of concrete. A method to calculate the diameter of spalling-protected concrete column around the fiber is proposed to describe quantitatively the effects of fiber size and content. The pore structure analysis shows that the porosity of the concrete sample will increase obviously after fire if the admixture can improve the spalling resistance. Moreover, the most probable pore diameter of the concrete sample will be enlarged and the pores with the most probable pore diameter occupy some certain content. Fireproof coatings can suppress spalling to some extent, but this depends on the properties of the coating.