火灾后纤维轻骨料混凝土力学性能试验研究

Experimental study on mechanical properties of fiber reinforced concrete with lightweight aggregate after high temperature of fire

为了研究纤维对火灾高温后轻骨料混凝土力学性能的影响,制作了15组分别掺入陶瓷纤维、镀铜钢纤维和陶瓷镀铜钢纤维的轻骨料混凝土标准立方体试块,按照国际标准ISO 834升温曲线进行火灾高温试验。分析了不同纤维种类和掺量对20、30、60 min明火高温后轻骨料混凝土的爆裂情况、质量损失率、抗压强度及抗压强度残余率的影响。试验结果表明:不同陶瓷纤维掺量的轻骨料混凝土均发生严重爆裂现象,镀铜钢纤维在改善轻骨料混凝土抗爆裂性能方面优于陶瓷纤维;受火30 min内,镀铜钢纤维掺量越大,轻骨料混凝土质量损失率越高,抗压强度下降越快;受火60 min后,相同镀铜钢纤维掺量轻骨料混凝土的质量损失率随着陶瓷纤维掺量的增加而降低,抗压强度和抗压强度残余率越高。

In order to study the influence of the fiber on mechanical properties of lightweight aggregate concrete after high temperature of fire,15 groups of standard cube compressive strength test cubes of lightweight aggregate concrete mixed with ceramic fiber,copper plated steel fiber and ceramic copper plated steel fiber respectively were made.The high temperature fire test was carried out according to the international standard ISO 834 temperature rise curve.The effects of different fiber types,contents on the burst,mass loss rate,compressive strength and residual compressive strength of lightweight aggregate concrete after high temperature of standard fire for 20,30,60 min were analyzed.The test results show that the lightweight aggregate concrete with different ceramic fiber content has serious burst phenomenon,and the copper plated steel fiber is better than ceramic fiber in improving the spalling resistance of lightweight aggregate concrete.Within 30 min after fire,the greater the content of copper coated steel fiber is,the higher the mass loss rate of lightweight aggregate concrete is,and the faster the compressive strength decreases.After being exposed to fire for 60 min,the mass loss rate of lightweight aggregate concrete with the same copper plated steel fiber content decreases with the increase of ceramic fiber content,and the higher the compressive strength and compressive strength residual rate.