纤维增强超高强混凝土防高温爆裂研究

对15组立方体抗压强度为116～143MPa纤维增强超高强混凝土(FRUHSC)试件,开展了ISO834火灾标准升温曲线下的高温爆裂试验,考察了水胶比、孔隙率、纤维类型及体积分数、试件尺寸对其高温爆裂的影响.结果表明:水胶比为0.15的超高强混凝土与水胶比为0.18时相比,具有更低孔隙率和更高强度,表现为爆裂程度更高;...

Spalling Prevention of Fibre Reinforced Ultra-high Strength Concrete(FRUHSC) Subject to High Temperature

The explosive spalling behaviour of 15 groups of fibre reinforced ultra-high strength concrete(FRUHSC) specimens with cubic compressive strength of 116-143 MPa was investigated subject to ISO834 standard heating condition. The effect of water-binder ratio, porosity, fibre type, fibre content, and dimention of specimens on spalling was investigated. Test results show that the UHSC with water-binder ratio of 0.15 has lower porosity and higher strength than that with water-binder ratio of 0.18 and which is more likely to undergo spalling. The addition of 1.00% corrugated ultra-fine steel fibre in volume, which is intended for improving the ductility of concrete at room temperature, cannot prevent spalling. The spalling of both ф100× 200 mm specimens and ф300× 300 mm specimens can be prevented by the addition of 0.15% polypropylene fibre in volume. No spalling is observed when UHSC with water-binder ratio of 0.15 encased steel columns with 0.50% short steel fibre and 0.15% polypropylene fibre in volume are subject to loadings in fire condition. The fire tests reveal that the spalling of UHSC in the loaded element can be prevented as long as following the proposed addition of hybrid fibres.