Study on Mechanical and Durability Performance of Repair Materials Incorporating Organic Light-Emitting Diode (OLED) Glass Powder

다국어 초록 (Multilingual Abstract)

Modern infrastructure is made up of structural concrete, which acts as the framework for all of these structures; however, because of the high weight of vehicles passing through them and the changeable conditions of the environment around them, it is exposed to wear and heavy deterioration. The most crucial challenge facing the developed and developing world in such cases is extending the service life of these structures. Unfortunately, using conventional cement for repairing these structures contributes to pollution, producing 8% of global CO2 emissions. Simultaneously, the rapid expansion of the display electronics industry has resulted in a surge of OLED and LCD glass waste, creating an urgent need for sustainable disposal strategies to prevent landfill overflow.
This current dissertation seeks to tackle such issues arising across the industry with a sustainable low-carbon repair mixture that utilizes organic light-emitting diode (OLED) waste glass powder as a supplementary cementitious material (SCMs). Unlike most SCMs used as sustainable yet inert additions, this study shows how the utilization of the waste glass helps not only in being eco-friendly but more importantly, enhances the performance of the repair material itself by maximizing the free alkali present in the cement matrix, thus resulting in secondary reactions for enhanced long-term durability. Through the evaluation of the feasibility, advantages, and drawbacks of the implementation of OLED glass, the dissertation analyzes the most effective solution for repairing concrete structures while simultaneously diverting e-waste and lowering the carbon emissions in the process.
This thesis comprehensively investigates the fresh properties, mechanical performance, and durability of rapid hardening concrete (RHC)
and ordinary Portland cement (OPC) mortars incorporating OLED waste glass powder (O-GP) as a supplementary cementitious material (SCM). In order to assess its feasibility for repair and strengthening applications, different proportions (from 0% up to 30%) of O-GP were considered as replacements of cement, keeping the water-to-binder (w/b) ratio constant at 0.425 for the concrete and 0.5 for the mortar.
The experimental test focused on analyzing the aspects of workability, mechanical strength, durability, and microstructure formation. This resulted in a detailed assessment of pozzolanic performance of O-GP in early-age RHC from 4 hours to 56 days and late-age mortars ranging from 7 to 112 days. Being essential for joint repairing operations, the bonding strength between the new and the old concrete was an important part of the testing process. Carbonation resistance was another essential aspect considered as one of the most significant factors contributing to long-term damage. A enhanced empirical prediction (EEP) model has been developed using non-linear regression on carbonation depth.
Based on results, 10% cement replacement with O-GP (O-GP10) emerges as the ideal ratio, showing significant enhancement of mechanical
performance for both RHC and mortar through micro-filler action and better pore refinement. Microstructure analysis carried out using MIP, SEM, and EDS showed that under ideal replacement levels, O-GP enhances the process of hydration and produces increased formation of C-S-H gel, leading to faster matrix development and densification of the paste. From MIP results, O-GP10 has proven effective in reducing macropores (size > 0.1 µm) and forming finer pores. While different mixing processes are involved in preparing RHC and mortar, increased glass powder level leads to enhanced workability. However, increasing the replacement ratio up to 20% or 30% brought about detrimental consequences when considering mechanical properties and durability. The increased amounts of O-GP have caused significant dilution effect, early appearance of ettringite and loss of strength, leading to more severe carbonation than OPC itself.
To conclude, the effectiveness of O-GP largely depends on the rate of substitution, which proves the need for maintaining the rate of substitution below 10%. In addition, the EEP equation developed in this study can be used as an effective tool for determining the service life of the repair materials based on their carbonation process. Collectively, the results of this study have proven that OLED waste glass powder is a very promising SCM that can be used to improve the performance of repair materials for concrete structures.

목차 (Table of Contents)

• Contents
• 1. Introduction 1
• 2. Literature review . 21
• 3. Analysis of OPC mortar incorporating OLED glass powder 62
• 4. The effect of OLED waste glass powder on early strength performance of rapid-hardening concrete . 116
• 5. Supplementary Carbonation Prediction Models of O-GP RHC and Mortars 170
• 6. Conclusions and Recommendations 203
• 7. Recommendations. 208
• [Reference] 210