預制混凝土簡支疊合板耐火性能試驗研究*
鄧利斌1，吳方伯1，周緒紅1，2，劉彪1，李鈞1,3
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（1 湖南大學土木工程學院，長沙 410082； 2 重慶大學土木工程學院，重慶 400044；3 中航建筑工程有限公司，長沙 410000）
［摘要］進行了2塊預應力和2塊非預應力簡支疊合板受火試驗研究，分析了鋼筋類別、板底是否涂抹水泥砂漿粉刷層對簡支疊合板耐火極限的影響。觀測了試件表面出現(xiàn)的滲水、粉刷層剝落和混凝土爆裂及外觀顏色變化等宏觀現(xiàn)象，研究了高溫下截面溫度場分布、試件彎曲變形的變化規(guī)律。試驗結果表明：相同火災條件下，預應力試件比非預應力試件更容易發(fā)生混凝土爆裂；所有試件均為跨中區(qū)域橫向受拉裂縫引起的彎曲破壞，破壞時各試件的跨中撓度較大、延性較好；預應力筋會產(chǎn)生高溫徐變和松弛，對構件高溫受力性能更為不利，常溫下等強配筋的預應力試件比非預應力試件耐火極限??；板底受力筋的溫度是影響疊合板耐火極限的主要因素，板底粉刷層能延緩板底受力筋的升溫，提高試件的耐火極限。［關鍵詞］疊合板; 簡支; 受火試驗; 耐火性能中圖分類號：TU378.5 文獻標識碼：A 文章編號：1002-848X(2015)12-0065-06Experimental study on fire resistance performance of simply supported precast concrete composite slabsDeng Libin1, Wu Fangbo1, Zhou Xuhong1，2, Liu Biao1, Li Jun1,3(1 College of Civil Engineering, Hunan University, Changsha 410082, China; 2 College of Civil Engineering, Chongqing University, Chongqing 400044, China; 3 Zhonghang Construction Group Co., Ltd., Changsha 410000, China)Abstract:The fire resistance performance of two prestressed and two non-prestressed simply supported precast concrete composite slabs were tested. The influences of rebar type and mortar cover on bottom slab on fire endurance of the simply supported precast concrete composite slabs were analyzed. The macroscopical phenomena of the specimens were observed including water penetration, spalling of mortar cover, concrete burst and exterior color change. The distribution of temperature field along the depth of slabs and the chang law of flexural deformation under high temperature were investigated. Test results indicate that under the same fire condition, the prestressed specimens are more likely to have concrete burst than the non-prestressed ones. All specimens were flexural failure mode caused by transverse tension cracks in the middle regions, and have large mid-span deflection and good ductility at failure. The prestressed specimens have low fire endurance compared with the non-prestressed specimens with equal reinforcement at room temperature, because the prestressed tendons would produce high-temperature creep and relaxation and lead to worse mechanical performance under high temperature. The temperature of reinforced tendon at bottom slab is the main influence on fire endurance of the composite slabs, and the protective layer of cement mortar could delay the heating of internal tendons and improve fire resistance of the specimens.Keywords:composite slab; simply supported; fire test; fire resistance performance
*國家自然科學基金面上項目(51278179)。作者簡介：鄧利斌，博士研究生，一級注冊結構工程師，Email：denglibin87@sina.com。
