請用此 Handle URI 來引用此文件:
http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/88808
標題: | 鋼纖維混凝土加速腐蝕試驗分析及長期循環鹽霧劣化後之力學行為研究 Analysis of Accelerated Corrosion Test and Study on Mechanical Behavior of Long-term Cyclic Salt Spray Deterioration of SFRC |
作者: | 鍾文國 Wen-Guo Chong |
指導教授: | 廖文正 Wen-Cheng Liao |
關鍵字: | 鋼纖維混凝土,鹽霧加速劣化試驗,貯鹽試驗,氯離子,耐久性,殘餘力學行為, Steel-fiber concrete,Salt spray accelerated deterioration test,Ponding test,Chloride ions,Durability,Residual strength, |
出版年 : | 2023 |
學位: | 碩士 |
摘要: | 如今許多文獻中已經證實鋼纖維的添加能解決高強度混凝土脆性破壞的模式,同時還能提升試體之韌性表現。台灣長年處於潮濕且高溫的環境,且結構構件長期承受工作載重下難免會產生裂縫,這樣的條件下會使外界氯離子更容易沿著裂縫進入到混凝土內部侵蝕鋼筋,進而影響結構的使用性及耐久性。
於是本研究以不同水灰比及鋼纖維取代率作為主要參數將鋼纖維混凝土梁經預裂後產生工作裂縫再放置於大氣中及鹽霧室進行加速劣化長達約2000天來探討真實環境下添加鋼纖維之混凝土梁經長期劣化後之殘餘力學行為,同時探討受腐蝕後之鋼纖維對於限制裂縫及內部鋼筋腐蝕所帶來的影響。另外一項實驗為貯鹽試驗,同樣以不同鋼纖維取代率作為設計參數製作試體,接著於試體上方蓋圍堰浸泡NaCl溶液長達約2000天,透過比色法及氯離子滴定來探討內部氯離子之擴散行為,同時也能將這兩種不同加速腐蝕方法之結果來作比較。 由貯鹽試驗的結果發現,試體之擴散係數有隨著鋼纖維取代率增加而下降的趨勢,表示鋼纖維的添加不僅不會破壞高強度混凝土原有良好抵抗氯離子的能力,反而會提升混凝土內部的緻密性,且隨著鋼纖維取代率的增加其阻隔氯離子侵入之效應會更加明顯,大幅提升了混凝土之耐久性。鹽霧加速劣化試驗的結果中顯示,預裂後放置於大氣中或是鹽霧室進行加速劣化之梁試體其力學行為並沒有明顯的下降,其原因為氯離子沿著裂縫進入到混凝土內部侵蝕鋼筋僅造成局部腐蝕的狀況,其餘未開裂處之鋼筋仍然能發揮良好的握裹力才導致殘餘強度沒有顯著的變化。 Many studies have verified that the addition of steel fibers can solve the brittle failure mode of high strength concrete and improve the toughness performance of specimens. Taiwan has been in a humid and high temperature environment for many years, and structural components are subjected to long-term loading, which inevitably leads to crack formation. Under such conditions, chloride ions from the environment can more easily penetrate into the concrete through cracks, corroding the reinforcement and affecting the serviceability and durability of the structure. Therefore, different water-cement ratios and the addition of steel fiber were used as the main parameters. Steel fiber-reinforced concrete beams with pre-cracking were placed in the atmosphere and a salt spray chamber for accelerated deterioration for approximately 2000 days. The aim was to investigate the residual mechanical behavior of steel fiber-reinforced concrete beams after long term deterioration in real environmental conditions, and to explore the influence of corroded steel fibers on crack restriction and internal steel corrosion.Another experiment conducted was the ponding test. Similarly, specimens were designed with different addition of steel fiber, and then immersed in NaCl solution for approximately 2000 days, using colorimetric method and chloride ion titration to investigate the diffusion behavior of internal chloride ions. This also allowed for a comparison of the results between these two different accelerated corrosion methods. The results of the ponding test showed a decreasing trend in diffusion coefficient with an increasing steel fiber, indicating that the addition of steel fibers not only does not compromise the ability of high-strength concrete to resist chloride ions but also enhances the density of the concrete and the effect of blocking chloride ion penetration, significantly improving the durability of the concrete. The results of the accelerated deterioration test in the salt spray chamber and in the atmosphere showed no significant decrease in the mechanical behavior of the cracked beams. This is because the ingress of chloride ions into the concrete through cracks only causes partial corrosion of the reinforcement, while the non-cracked reinforcement maintains good bonding, resulting in no significant change in residual strength. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/88808 |
DOI: | 10.6342/NTU202302461 |
全文授權: | 同意授權(限校園內公開) |
顯示於系所單位: | 土木工程學系 |
文件中的檔案:
檔案 | 大小 | 格式 | |
---|---|---|---|
ntu-111-2.pdf 目前未授權公開取用 | 14.56 MB | Adobe PDF | 檢視/開啟 |
系統中的文件,除了特別指名其著作權條款之外,均受到著作權保護,並且保留所有的權利。