火害後自充填混凝土複合纖維圍束補強之研究

Abstract

自充填混凝土乃屬較新的材料，且應用日廣，而據消防暑之統計，近年火災有快速增加的趨勢，故火害後自充填混凝土之力學行為就顯得相當重要。而複合纖維補強為現今較常用的補強方法，因此本研究除探討自充填混凝土強度與火害溫度之關係外，並針對火害後的試體經纖維補強後的強度回復做一系列的試驗，探討纖維圍束對火害後試體的補強關係。 本研究主要目的第一為探討自充填混凝土在遭受火害後，其殘餘強度、殘餘應變等力學性質的變化，由實驗數據迴歸一近似的關係式，並與前人所做的研究成果相比較，評估其合理與否。第二是將火害後的試體予以包覆纖維補強，使混凝土試體的殘餘強度能夠回復原先的強度。實驗所模擬的火害延燒時間為0.5小時、1.0小時、1.5小時、2.0小時、2.5小時、3.0小時等六段；最後再找出圍束效應與試體殘餘強度的關係性，作為結構物補強的最佳參考。由實驗結果得知，(1) SCC與OPC在相同設計強度，若受相同火害溫度，會有類似的火害後強度折損，亦即，SCC受火害後的強度折減，並不會比OPC來的嚴重。(2) 常溫下不同設計強度的纖維補強試體，相同纖維層數圍束下，強度愈低，所產生的圍束力有較高的現象。(3) 以10cm×20cm的火害試體做纖維包覆補強而言對於中強度210kg/cm2 系列的試體皆能回復原強度，但對420kg/cm2系列試體則未皆能回復原強度，欲補強至原強度，則需做更多層的纖維補強。(4)本研究所推導之分析公式計算值與實驗值結果相差無幾。

Self-Compacting Concrete is a new material, and is widely used in these days. According to the statistics of Fire Administration, the occurrence of fires has been increasing in a fast trend. The mechanic behavior of self-compacting concrete after the fire damage is thus very important. The composite fiber confinement is used to repair concrete strength recently. The objective of this research also studying the relationship of strength and fire temperature of self-compacting concrete, and Self-Compacting Concrete strengthening with composite fiber is also investigated. The SCC specimens was fired exposed to different high temperatures. The temperature rice follows ASTM E119 and the test times are 0.5 ,1.0 ,1.5 ,2.0 ,2.5 ,3.0 hours. The result can be used practice engineers to determine the method and materials to be used for strengthening. From the test results, it is found that (1)the residual strength of OPC and SCC after fire is about the same,(2)the effectiveness of fiber strengthening is better for lower strength concrete,(3)the strengthening of fire damaged concrete can recover to its original strength for 210 kgf/cm2 concrete specimens with only one layer of composite . However , for 420 kgf/cm2 concrete , it may need 2 or more layers to recover its strength and (4)the empirical equation agree well with the test data. KEY: Self-Compacting Concrete、fire damage、repairing、carbon fiber、glass fiber、confinement