無機聚合物工程特性及影響因素暨應用於混凝土缺陷修補研究

A Study on Engineering Properties with Impact Factors of Geopolymer and its Application on Repairing Concrete Defects

呂軒志(Syuan-Jhih Lyu)

指導教授 ： 翁祖炘 ； 鄭大偉 ； 王泰典

國立臺北科技大學/工程學院/工程科技研究所/博士(2013年)

https://doi.org/10.6841/NTUT.2013.00464

摘要

修補材料為構造物修復工程的關鍵因素，目前修補成效之評估亦無相應之準則與方法。而無機聚合物組成與混凝土相近，具低二氧化碳排放、高早強度、耐久性佳、低體積變化率、可作填充承壓材等特性，在混凝土缺陷修補方面極具發展潛力，更為近年來備受矚目之綠色環保材料。
本研究於實驗設計法之架構下，旨探討無機聚合物之影響因素、工程特性及黏結特性。研究首先利用統計學中複迴歸分析，釐清無機聚合物不同組成分間之交互作用，並掌握組成成分與微結構特徵及力學特性間之關係。爾後基於混凝土裂縫修補特性提出一簡單力學模式，並透過一系列含不同夾層傾角的黏結試驗，探求介面上之黏結特性及修補後再破壞特徵。最後配以顆粒力學個別元素法進行模擬，據以掌握無機聚合物修補混凝土缺陷後介面黏結行為。
研究結果顯示，在無機聚合物力學特性方面，影響因子以OH- (M)為主，與SiO2 (mol)有交互影響作用。OH-濃度越高無機聚合物之視凝聚力及聚合程度亦隨之增加，而OH-與SiO2搭配比例不同，可形成不同的Q4(nAl)配位結構進而造成力學特性差異。此外，無機聚合物破壞模式受聚合程度與應力狀態影響顯著，於單軸壓縮條件下呈脆性破壞特徵，圍壓上升漸轉變為略具延性之特性。在修補黏結方面，提出的力學模式，可考量無機聚合物修補混凝土缺陷後介面之黏結特性。依介面強度參數繪製之夾層試體受力破壞包絡線，可判斷不同受力狀態下之破壞模式。另透過實驗得知，以水淬高爐石添加燃煤飛灰製備之無機聚合物介面黏結力最佳，黏結介面之正向勁度與正向應力具指數之關係，整體之修補成效無論圍壓大小皆可高達95%以上。在數值模擬方面，採個別元素法可明確模擬出無機聚合物、水泥砂漿基材及修補後不同夾層傾角試體在單軸壓縮試驗條件下之力學行為及破壞形態，模擬所得結果皆吻合試驗值。本研究運用實驗設計法及統計分析方法，無論是於無機聚合物力學特性方面或數值模擬，所提出之複迴歸方程式，模式可靠度皆可達80%以上，極具參考之價值與意義。

關鍵字

無機聚合物 ； 實驗設計 ； 力學特性 ； 微結構特徵 ； 修補力學模式 ； 介面黏結特性

並列摘要

Repair materials are key factors for structure restoration projects. Currently, however, no corresponding standards or methods exist for evaluating repair effectiveness. The formation of geopolymer is similar to concrete; it has low carbon dioxide emissions, high early strength, good durability, low volume change rate, and can be used as a pressure-bearing filler material. Geopolymer possesses great developmental potential for concrete defect repairs and has received much attention in recent years as an environmentally friendly material.
Based on the framework of experimental design, this study investigates the influence factors, engineering and adhesion properties of geopolymer. First, statistical regression analysis is used to clarify the interaction between geopolymer constituents, and to understand the relationships between compositions, microstructure characteristics and mechanical properties. Secondly, a simple mechanical model is proposed to describe the repair properties of geopolymer on concrete cracks. After a series of adhesion tests with different layered angles, the adhesion properties and re-failure features of geopolymer-concrete interface are defined. In addition, the simulations of distinct element method are utilized to grasp the interface adhesion behavior of geopolymer after repairing concrete defects.
Study results indicate that OH- (M) is the primary influential factor in geopolymer mechanical properties, and has an interaction with SiO2 (mol). As the OH- concentration increases, the geopolymer’s apparent cohesion and extent of polymerization also increased. Different proportions of OH- and SiO2 can form different Q4 (nAl) coordination structures, subsequently causing differences in mechanical properties. In addition, stress and extent of polymerizations had a significant effect on the geopolymer failure model. Under uniaxial compression conditions, geopolymer exhibited brittle fracture characteristics. As confining pressure increases it gradually changed to a slightly ductility characteristic. For repair adhesion, proposed mechanical models may consider the adhesion characteristics after repairing concrete defects with geopolymer. Plotting the stress damage envelope of layered specimens according to interface strength parameters can determine the damage model under different stress conditions. The experiments also showed that adding coal fly ash and granulated blast furnace slag to geopolymer lead to optimal interface adhesion strength. The normal stiffness of the adhesion interface and normal stress has an exponential relationship. Overall, the repair effectiveness can achieve above 95% regardless of confining pressure. For numerical simulation, the distinct element method can accurately simulate the mechanical behavior and damage pattern of specimens with different geopolymer, mortar substrate, and repair layer angles under uniaxial compression experiment conditions. The simulated results all conformed to the experiment value. This study used experimental design and statistical analysis. For geopolymer mechanical properties and numerical simulation, the proposed multiple regression equation achieved a model reliability of above 80%, which possesses reference value and significance.

並列關鍵字

Geopolymer ； Design of Experiments ； Mechanical properties ； Microstructural characteristics ； Mechanics model ； Adhesion

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