Pomza tozu ve porselen parlatma atığının ultra yüksek performanslı betonlarda puzolanik malzeme olarak kullanılabilirliğinin araştırılması = Investigation of the use of pumice powder and porcelain polishing waste as pozzolanic material in ultra high performance concrete

Abstract

This study focuses on investigating alternative materials that can effectively replace the costly silica fume (SD) in the production of ultra high performance concrete (UYPB). UYPB is a highly advanced construction material renowned for its exceptional compressive strength and superior physical properties, which make it suitable for a wide range of demanding applications in the construction industry. Typically, UYPB formulations incorporate SD in conjunction with cement to enhance the material's performance characteristics, including durability, workability, and resistance to environmental factors. However, the high cost associated with SD significantly increases the overall expense of UYPB production, which can be a limiting factor for its widespread adoption, particularly in regions where budget constraints are critical. Consequently, the search for economical alternatives to SD is not only important but also urgent, as it can facilitate the broader use of UYPB in various construction projects. In light of these considerations, this research aims to explore locally available and more affordable materials that can serve as effective substitutes for SD. Specifically, the study examines finely ground pumice powder (PT) and porcelain polishing waste powder (PPAT) as potential alternatives. Pumice is a naturally occurring volcanic rock that possesses pozzolanic properties, which can enhance the performance of concrete mixtures. Similarly, porcelain polishing waste, a by product of the porcelain manufacturing process, is rich in silica and can contribute to the pozzolanic activity of concrete. By investigating these alternative materials, the study seeks to evaluate their feasibility in UYPB formulations, aiming to maintain or even improve the mechanical and physical properties of the concrete while reducing production costs. This research not only addresses the economic challenges associated with UYPB production but also promotes the use of sustainable materials that can contribute to environmental conservation by utilizing industrial by products. Ultimately, the findings of this study could pave the way for more cost effective and sustainable practices in the concrete industry, enhancing the accessibility and applicability of UYPB in various construction contexts. Research Methodology In our study, ultra high performance concrete (UYPB) mixtures were meticulously prepared by substituting silica fume (SD) with varying proportions of finely ground pumice powder (PT) and porcelain polishing waste powder (PPAT). This substitution aimed to explore the potential of these alternative materials to maintain or enhance the performance characteristics of UYPB while reducing production costs. To achieve a comprehensive understanding of the impact of these substitutions, the mechanical and physical properties of the resulting UYPB mixtures were thoroughly evaluated. The assessment of fresh UYPB mixtures included several critical parameters. Specifically, we measured the spread diameter, which is an indicator of workability, and the fresh concrete density, which provides insights into the material's composition and potential strength. Additionally, we examined the rheological properties of the mixtures, as these characteristics are crucial for ensuring proper flow and placement during the pouring process. For the evaluation of hardened concrete, a series of tests were conducted at specified intervals namely on days 7, 14, and 28 post-mixing. These tests included measurements of density, which helps to assess the compactness of the concrete; ultrasonic pulse velocity, which serves as a non-destructive method to evaluate the quality and integrity of the concrete; and both flexural strength and compressive strength, which are essential indicators of the material's load bearing capacity and durability. The primary objective of these tests was to evaluate the effects of different material combinations on the overall performance of the concrete. By systematically analyzing the results, we aimed to determine how the incorporation of PT and PPAT as substitutes for SD influenced the mechanical properties of UYPB. Particularly noteworthy is the significance of rheological properties in fresh concrete, as they directly affect the ease of placement and the quality of the finished product. Therefore, parameters such as spread diameter and viscosity were meticulously measured to ensure that the mixtures not only met performance standards but also facilitated efficient handling and application on construction sites. This comprehensive evaluation process is crucial for understanding the viability of using PT and PPAT in UYPB formulations, paving the way for more sustainable and cost effective concrete solutions. Results and Discussion The results of our comprehensive investigation into the use of pumice powder (PT) and porcelain polishing waste powder (PPAT) as partial replacements for silica fume (SD) in ultra high performance concrete (UYPB) production were highly encouraging. Both PT and PPAT exhibited pronounced pozzolanic activity, a crucial characteristic that enables these materials to actively participate in the chemical reactions within concrete and contribute to its strength development. The pozzolanic nature of PT and PPAT allowed for the formulation of UYPB mixtures, such as PT40, PT50, and PPAT40, where 40% or 50% of the SD content was replaced by these alternative materials. Remarkably, these mixtures maintained excellent mechanical properties, including compressive and flexural strength, without compromising the overall strength and durability of the concrete. This finding is particularly significant as it demonstrates the potential of PT and PPAT to serve as effective partial substitutes for SD in UYPB production. As the replacement ratio of PT and PPAT increased in the UYPB mixtures, certain changes were observed in the fresh concrete properties. Specifically, the density and spread characteristics of the fresh concrete samples were affected, with a general trend of decreasing density and spread diameter as the replacement ratio increased. This observation was particularly pronounced in samples containing 10% PT and PPAT, which displayed a significant reduction in density compared to the reference UYPB mixture. However, the most notable finding was that substituting PT and PPAT at 40% and 50% ratios resulted in significantly higher compressive strengths on days 7, 14, and 28 compared to the reference UYPB mixture. This remarkable improvement in compressive strength can be attributed to the pozzolanic activity of PT and PPAT, which positively influences the chemical reactions within the concrete, leading to enhanced strength development. Similar trends were observed in the flexural strength results, where the PT40, PT50, and PPAT40 mixtures consistently outperformed the reference UYPB on days 7, 14, and 28. However, it is important to note that a 50% addition of PPAT led to a decrease in flexural strength values over the same periods. This finding suggests that while PT and PPAT can effectively serve as partial replacements for SD in UYPB production, the optimal replacement ratio may vary depending on the specific properties being targeted. Overall, these results clearly demonstrate the potential of pumice powder and porcelain polishing waste powder to enhance the performance of ultra high performance concrete. By leveraging the pozzolanic activity of these alternative materials, it is possible to produce UYPB mixtures with improved mechanical properties while reducing the reliance on costly and resource intensive materials like silica fume. These findings open up new avenues for the development of more sustainable and cost-effective UYPB solutions, contributing to the advancement of the construction industry. Rheological Properties The study also investigated the effects of yield stress and plastic viscosity on the rheological properties of fresh concrete. The substitution of PT and PPAT significantly influenced the thixotropic behavior of the mixtures. An increase in PT substitution correlated with higher thixotropic values, although a tendency to decrease was observed at a 50% replacement ratio. Similarly, PPAT substitution enhanced thixotropic behavior, reaching its peak value at a 50% replacement ratio. These additives can improve the rheological properties of fresh concrete; however, careful optimization of the substitution ratios is necessary. The importance of rheological properties during the pouring and processing of concrete is emphasized, as suitable rheological characteristics facilitate the placement and compaction of concrete. Environmental Sustainability The findings also highlight the environmental sustainability benefits of using these materials. Puzzolans can contribute to reducing environmental impacts by reusing industrial waste in concrete production. Specifically, the utilization of industrial by-products like porcelain polishing waste offers an innovative solution to waste management issues. The use of PT and PPAT can contribute to a greener concrete production process by reducing the carbon footprint. This represents a significant step towards sustainable construction practices, while also aiding in the conservation of natural resources. Future Research Directions Future research could explore the effects of these materials on different types of concrete, contributing to broader applications in the construction industry. Investigating the early age (0-28 days) and later age (56-365 days) effects of both pumice powder and porcelain polishing waste powder on the strength development of ultra high performance concretes will be essential for promoting their use. Additionally, studies on the long-term performance and durability characteristics of PT and PPAT will help in gaining wider acceptance and adoption of these materials. Such research could provide insights into the potential chemical and physical changes these materials undergo, enhancing our understanding of their long term performance in UYPB. Examining the behavior of these materials under various environmental and climatic conditions is also crucial. Conclusion In conclusion, pozzolanic activity is a vital process that enhances the mechanical properties of construction materials. This study established that both pumice powder (PT) and porcelain polishing waste powder (PPAT) exhibit pozzolanic activity and can be effectively used as binders in concrete mixtures. As the replacement ratio of PT and PPAT in UYPB increased, the density and spread characteristics of fresh concrete samples were affected, generally showing a decrease in density and spread diameter. The substitution of PT and PPAT at 40% and 50% ratios yielded higher compressive strengths on days 7, 14, and 28 compared to the reference UYPB, although a decrease in flexural strength was noted with 50% PPAT. These results demonstrate the potential of PT and PPAT as effective binders in UYPB production, enhancing concrete performance while promoting cost effectiveness and environmental sustainability.