輕質骨材混凝土受高溫後之性質

Abstract

輕質混凝土由於質輕,若使用在高層結構物上,可降低結構物之重量,減輕 地震力的作用,另外還具有良好的耐火性能.由於近年來許多建築物火災, 造成不少的傷亡及財產損失,故本研究主要目的乃在探討輕質骨材混凝土 之耐火性能,並與一般常重混凝土比較.本文之研究主要針對不同比重骨材 混凝土依ASTM E119 標準昇溫曲線加溫三小時至1052℃,冷卻後放置至不 同時間之殘餘強度恢復,重量變化,動彈性模數,超音波波速之變化情形,及 加溫過程中混凝土內部各點之溫度變化情形,另外還量測混凝土之熱膨脹 係數及不同溫度時之極限熱應變量,由所得結果可知,混凝土受火害後產生 之裂縫,隨著所用骨材比重的降低,裂縫則較少,且較不明顯,而火害後之混 凝土抗壓強度,動彈性模數,超音波波速,則有相同的趨勢,即骨才比重越 低,受高溫後之折減越少,另外輕質骨材混凝土之熱應變量,熱膨脹係數,熱 傳導均較一般常重混凝土為低,由此顯示輕質骨材混凝土之耐火性能均較 常重骨材混凝土為佳.故若應用於房屋結構上應可有效減低火災發生時之 傷害. If the light-weight concrete is used in building a high rise ,it can reduce building'sweight because of its weight is lighter than the normal-weight concrete,and reduce the process of earthquake corresponding.On the other side,its fire proof properties are better than the normal-weight concrete.In these years,fire damage made great losses of life and money,if we want to employ the light-weight concrete to building structure, it is necessary to research its thermal properties in the process of a fire. The research has different aggregates of four specific gravity in making concrete,heated with ASTM E119 standard fire temperature-time relation to 1052 ℃,measure their surplus strength,weight,dynamic elastic modulus, ultrasonic velocity after cooling,temperature-time relation in concrete interior during heating,and concrete's extreme thermal expansion strain, thermal expansion cofficient. With the result that we can see the thermal properties of the light-weight concrete after a fire are better than the normal-weight concrete,so if a construction is built in the light-weight concrete,it can reduce fire damage effectively.