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碩士論文公告區 |
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| 年度： | 92 | |
| 姓名： | 陳德原(Te-Yuen Chen) | |
| 論文題目(中)： | 品質不良之混凝土劣化後基本性質及修補後破裂性之研究 | |
| 論文題目(英)： | The Study of Fundamental Property and Repaired Fracture Toughness of Poor-Quality Concrete after Deterioration | |
| 摘要(中)： | ||
| 混凝土品質對結構物有相當大的影響，在施工、運送、拌製時，往往為了較好的工作性或為了增加混凝土的單位體積而私自加水，造成混凝土的品質受到影響，而影響到結構物安全，在以上問題之研究過程中，有關強度及破壞力學特性等議題，已有相當多的探討及成果，較少對於混凝土品質改變後，再經長期劣化混凝土之破裂韌性進行研究，對於沿海環境重要結構物使用年限評估和安全性可提供參考。 在新拌混凝土中，水灰比增加時，坍度增加、單位重減少、空氣含量減少，抗壓強度會遞減，其控制組的抗壓強度也較劣化組高；三組配比之彈性模數隨齡期增加，水灰比w/c=0.53及0.60之劣化組較控制組高，在w/c=0.70時，控制組較劣化組高，在ACI彈性模數之經驗公式迴歸E值，在固定強度下劣化組都較控制組高；臨界應力強度因子經驗公式發現，實驗中求得之劣化組與控制組之臨界應力強度因子都高於經驗公式；三組配比的劣化組樑試體承載力經修補後修復指數，隨著齡期增加而減少，由此可知，劣化越久樑試體修補成效越差；破裂能之修復指數趨勢不甚明顯，但皆有達148%以上，甚至有高達297%；故使用環氧樹脂修補後，可以有效增加樑試體的延展性；採用非破壞的敲擊回音法去了解硬固混凝土之變化，當水灰比增加時，波速會跟著往下降，當劣化組受乾溼循環後，其波速也較控制組低。 |
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| 摘要(英)： | ||
| Concrete quality indeedly influences on the safety of structure. Workers sometimes improperly add extra water into the mixed before placing the concrete in order to maintain a better workability. While this action will lead to a induction of strength or decay in mechanical properties. Plenty of researches have been conducted dealing with those areas, but few have been done on the deterioration of concretes for their fracture properties. It is felt significant to study the fracture toughness of deteriorating concrete exposure in marine environment to assess the safety of structure. From the test results, it was found that for a given mixture of concrete, the slump increases but its unit wt air content and compressive strength reduce as water-to-cement ratio increases. Compressive strength is higher for concrete cured in water than those cured in seawater. While this trend is reversed for elastic modulus. Elastic modulus and KIC grow with the curing duration for both conditions. GF turns out higher for the repaired concrete than those unoracked concrete. This implies a improvement in its ductility. The restoration efficiency appears reduced as the deteriorating duration increases. The wave velocity shows decreasing as W/C increases, and the deteriorated concrete appears a lower wave velocity. |
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| 檔案： | 沒有相關檔案 | |
| 相關連結： | http://ethesys.lib.cyut.edu.tw/ETD-db/ETD-search-c/view_etd?URN=etd-0810104-203437 | |