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Title: | 自充填混凝土收縮潛變行為及其預測模型 Prediction Model for Shrinkage and Creep Behavior of Self-Compacting Concrete |
Authors: | 阮平段 Nguyen Doan Binh |
Advisor: | 廖文正 Wen-Cheng Liao |
Keyword: | 潛變,收縮,依時變形,資料庫,預測模型,自充填混凝土,卜作嵐材料, creep,shrinkage,time-dependent deformation,database,prediction model,self-compacting concrete,pozzolanic material, |
Publication Year : | 2023 |
Degree: | 博士 |
Abstract: | 收縮和潛變是兩種隨時間持續增加的變形,它們顯著影響混凝土結構的體積穩定性及使用性,尤其是漿體量高的自充填混凝土(SCC)。國內外已經有許多預測模型來評估混凝土結構之收縮潛變,惟大多數可都是針對傳統混凝土,雖然也有一些模型針對SCC進行了修正;然而這些模型在預測SCC的收縮和潛變仍不甚準確,尤其是自體收縮和基本潛變之準確性仍偏低。此外,現今產官學界仍缺乏SCC完整的收縮潛變的實驗數據資料庫。
本研究重點開發B4TW-SCC模型來預測SCC之收縮和潛變,並廣泛蒐集國內外1995年至2021年間SCC研究論文以最佳化預測模型;本研究也建置了國內外最完整SCC資料庫,命名為NTU-SCC,該資料庫包括1316個收縮試驗資料集和266個潛變試驗資料集(每個資料集中含該次試驗之所有資料點),並利加權分析確定修正收縮和潛變預測模型參數。本研究也進行了研究卜作嵐摻料(包括飛灰和水淬高爐爐碴粉)不同替代水泥量(重量比不超過40%)之SCC收縮和潛變行為影響的實驗,其中水膠比在0.36-0.48間。研究發現礦物摻料、水膠比等多種因素影響SCC的新拌和硬固性質,實驗結果也與預測模型的預測值進行了比較。B4TW-SCC模型對自體收縮、彈性模數、配比組成等參數進行最佳化;與ACI 209R-92模型、B4模型、fib MC2010等其他模型相比,B4TW-SCC在預測SCC自體收縮、總收縮、基本潛變和總潛變具有最佳的準確性。 Shrinkage and creep are two notable time-dependent deformations that significantly influence the dimensional stability and serviceability of concrete structures, particularly for self-compacting concrete (SCC) due to its higher paste amount. Many prediction models have been developed over the years to estimate these time-dependent deformations on the concrete structure. While most of the available models were designed for conventional concrete, a few models were modified for SCC. However, these models still have low accuracy in predicting shrinkage and creep of SCC, particularly autogenous shrinkage and basic creep of SCC. Besides, the lack of a database was collected for shrinkage and creep of SCC. This research focused on developing the B4TW-SCC model to predict the strains of SCC due to shrinkage and creep. The calibration of the prediction model was optimized to fit the NTU-SCC database, which includes 1316 datasets of shrinkage tests and 266 datasets of creep tests based on numerous published research papers for SCC from 1995 to 2021. The optimum strategy was introduced on the weighting scheme to determine the shrinkage and creep prediction model parameters. Furthermore, the experiment was carried out to investigate the influences of pozzolanic materials, including fly ash and slag, as partial replacement of cement with different contents up to 40% by weight on shrinkage and creep behavior of SCC was carried out. The different water to cementitious material ratios in the range of 0.36–0.48 were also tested on shrinkage behavior. The study found that many factors, such as mineral admixture and water to cementitious material ratio, influenced the fresh and hardened properties of SCC. The experimental results were also compared to the calculated values of prediction models. The B4TW-SCC model was improved on adjusted formulae of autogenous shrinkage, elastic modulus formula, new average composition, and optimized parameters. Therefore, this model resulted in the best accuracy to predict autogenous shrinkage, total shrinkage, basic creep, and total creep of SCC in comparison with other models such as the ACI 209R-92 model, B4 model, fib MC2010, as well as the prediction models of SCC and the tested shrinkage and creep. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/88477 |
DOI: | 10.6342/NTU202302094 |
Fulltext Rights: | 同意授權(全球公開) |
Appears in Collections: | 土木工程學系 |
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ntu-111-2.pdf | 16.51 MB | Adobe PDF | View/Open |
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