高強度鋼纖維混凝土版之壓桿行為實驗研究

EXPERIMENTAL INVESTIGATION ON ISOLATED STRUT BEHAVIOR OF HIGH STRENGTH STEEL FIBER REINFORCED CONCRETE PANELS

郭珈均(Chia-Chun Kuo) ； 洪崇文(Chung-Wen Hung) ； 廖文正(Wen-Cheng Liao)

《中國土木水利工程學刊》 32卷4期 (2020/06) Pp. 367-375

https://doi.org/10.6652/JoCICHE.202006_32(4).0008

摘要

各國陸續推廣與發展高強度混凝土，然而設計上需採大量剪力筋以防脆性破壞，容易導致施工困難。透過添加鋼纖維於混凝土中，能有效抑制裂縫發展，並取代部分橫向鋼筋，解決箍筋綁紮過密的問題。為了探討高強度鋼纖維混凝土於力量不連續區的力學行為，本研究採用鋼纖維體積取代率、鋼筋配置之位置與強度作為三個設計參數，製作出24座高強度鋼纖維混凝土薄版試體，並進行直壓試驗，期望透過實驗結果釐清其力學原理與行為。結果顯示，隨著鋼纖維的添加，試體由脆性劈裂破壞轉變為壓桿擠碎破壞，且開裂與極限強度皆能提升。透過分析不同的壓桿形狀，以有效拉桿面積來評估鋼纖維於瓶狀壓拉桿內的拉桿貢獻，由計算結果得知，鋼纖維體積取代率0.75%及1.5%的試體，可分別提升40%及50%之拉桿有效面積。

關鍵字

鋼纖維 ； 平版 ； 高強度混凝土 ； 壓桿行為

並列摘要

High strength reinforced concrete have been promoted and developed in recent years. Due to brittle nature of high strength concrete, higher amounts of transverse reinforcement are required to ensure the ductility of members. By adding steel fiber into high strength concrete, which is so-called steel fiber reinforced concrete (SFRC), shear strength and deformation capacity can be significantly improved and damage tolerance is also enhanced because cracks can be restrained effectively. Moreover, SFRC is expected to replace certain amount of transverse reinforcement for better construction workability. In this study, uniaxial compression tests of 24 SFRC panels were conducted to verify strut mechanism and behavior of SFRC in the isolated strut. The result results show that the addition of steel fiber not only changes the failure mode from brittle splitting failure to ductile strut crushing, but also increases both strengths at the first-cracking and ultimate stages. Furthermore, by analyzing different shapes of strut, an index named effective tie area is proposed to verify tensile force contributed from steel fiber in the bottle-shaped strut. The results indicate that in the specimen with 0.75% and 1.5% volume fraction of steel fiber, effective tie area can raise up to 40% and 50%, respectively.

並列關鍵字

steel fiber ； panel ； high strength concrete ； strut behavior