纤维增强超高强混凝土防高温爆裂研究  

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

作　　者：杜咏[1] 严奥宇 戚洪辉 DU Yong;YAN Aoyu;QI Honghui(College of Civil Engineering, Nanjing Tech University, Nanjing 211816, China)

机构地区：[1]南京工业大学土木工程学院,江苏南京211816

出　　处：《建筑材料学报》2021年第1期216-223,共8页Journal of Building Materials

基　　金：国家自然科学基金资助项目(5167081607)。

摘　　要：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;为改善常温下混凝土延性而掺入体积分数1.00%的熔抽超细型钢纤维并不能防止其高温爆裂;掺入体积分数0.15%的聚丙烯纤维可防止Φ100×200mm试件高温爆裂,并适用于Φ300×300mm试件.对水胶比为0.15、混掺体积分数为0.15%聚丙烯纤维及0.50%熔抽超细型钢纤维的超高强混凝土型钢组合柱进行高温加载试验后发现,型钢外包混凝土未发生高温爆裂,表明所建议的混掺纤维体积分数在构件受荷时可防止高温爆裂.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.

关 键 词：纤维增强超高强混凝土 高温爆裂 聚丙烯纤维 钢纤维 

分 类 号：TU528.31[建筑科学—建筑技术科学]