预制混凝土无机保温夹心外墙体抗火性能试验研究

Experimental study on fire resistance of precast concrete inorganic insulation sandwich walls

为了研究内、外叶钢筋混凝土墙板、无机保温砂浆板及FRP连接件组成的预制混凝土无机保温夹心外墙的抗火性能,按照ISO 834升温曲线对其进行抗火性能试验,试件包括:有保温层墙体W1(受火60 min)、无保温层墙体W2(受火60 min)和有保温层墙体W3(受火180 min)。研究表明:3个试件沿截面厚度方向温度场呈非线性分布,外叶墙距迎火面30 mm范围内,温度梯度较大,而内叶墙温度受火灾影响较小;试件W1、W2和试件W3跨中区域的背火面平均温升分别为10.7、29.7℃和49.5℃,FRP连接件最高温度分别为435.5、389.4℃和763℃;实测最大跨中挠度分别为14.2、51.7 mm和102.3 mm,无机保温砂浆板可增加墙体抗弯刚度,减小墙体挠度;试件W1、W2在受火60 min情况下,满足GB/T 9978.1—2008《建筑构件耐火试验方法》和ASTM E119所规定的完整性、隔热性和变形等要求,试件W3在受火180 min情况下,墙体耐火极限约为89 min。

The paper investigates the fire resistance of a new type of precast concrete sandwich wall which is composed of inner and outer concrete wythes,inorganic insulation mortar and fiber reinforced plastic( FRP) connectors. A total of three specimens,including: specimen W1 with insulation layer,specimen W2 without insulation layer( fired for 60minutes),as well as specimen W3 with insulation layer specimen( fired for 180 minutes),were exposed to ISO 834 standard fire for 60 minutes or 180 minutes. The test results reveal that the temperature field along the thickness direction for all specimens is nonlinearly distributed. The temperature gradient is large in the outer wythe,which is30 mm distant from exposed fire surface. The temperature of the inner wythes for all specimens is low,which is not affected significantly by the fire. The average temperature of unexposed surface for specimens W1 to W3 rise 10. 7 ℃,29. 7 ℃ and 49. 5 ℃,respectively. The highest temperature of FRP connectors for specimens W1 to W3 are 435. 5℃ 、389. 4℃ and 763℃,respectively. The maximum mid-span deflections for specimens W1 to W3 are 14. 2mm,51. 7mm and 102. 3mm,respectively. The inorganic insulation mortar can increase the flexural stiffness of sandwich walls,which decreases deflection of sandwich walls. The specimens W1 and W2 can satisfy the( GB / T 9978. 1—2008)‘Fire-resistance tests: elements of building construction'and ASTM E119 provisions. The fire resistance of precast concrete inorganic insulation sandwich wall is approximately 89 minutes.