This study explores the performance of alkaline-activated geopolymer binders using industrial by-products and recycled concrete fine aggregate (RCFA) as sustainable alternatives to traditional cement. Materials such as granulated blast furnace slag (GBFS), silica fume (SF), red brick powder (RBP), quick lime (QL), and RCA were utilized to develop eco-friendly binders with enhanced mechanical and durability properties. Experimental tests evaluated physical, mechanical, and microstructural characteristics, including setting times, dry density, flexural strength, and compressive strength. Advanced analysis with SEM and EDAX examined aggregate-binder bonding. Results highlighted the critical role of binder composition in determining performance. Balanced mixtures of GBFS, SF, and RBP achieved superior strength, durability, and compact microstructures, while excessive QL increased porosity, reducing effectiveness. Optimal flexural strength (4.24 MPa at 56 days) was observed for the G30/S40-L20 formulation, underscoring the importance of precise proportions. Composition influenced setting times, with SF delaying gelation and high QL content accelerating it. The findings demonstrate the viability of using RCFA and industrial by-products in sustainable construction, offering a pathway to reduce reliance on traditional cement. The study emphasizes optimizing binder formulations for strength and durability while addressing environmental impacts, encouraging further research into long-term performance under diverse conditions. This innovative approach highlights the potential for integrating recycled and industrial by-products into construction practices to achieve eco-friendly solutions and promote sustainable urban development. Doi: 10.28991/CEJ-2025-011-02-018 Full Text: PDF

The rapid growth of Natural Fiber Laminate (NFL) innovation is a direct response to environmental challenges, positioning these materials as superior alternatives to synthetic fiber composites. This paper delved into the outcomes of an extensive experimental study investigating the influence of sisal fiber (SLF), banana fiber (BF), and glass fiber (GF) on the mechanical and microstructural characteristics of concrete. The water absorption curves were established for sisal fiber concrete (SLFC), banana fiber concrete (BFC), and glass fiber concrete (GFC). Furthermore, Scanning Electron Microscope (SEM) observations were conducted to perform microanalysis and failure analysis of the tested specimens. The results revealed significant improvements in the concrete containing fibers compared to its counterpart in fiber-free concrete. For mixtures with a water-to-binder (W/B) ratio of 0.3, the most optimal mix (GF-30-135) showed improvements in compressive strength, flexural strength, and splitting tensile strengths by 4.13%, 8.93%, and 10.10%, respectively. On the other hand, for W/B of 0.4, mix GF-30-135 showed improvements of 5.05%, 8.55%, and 11.60%, respectively. Furthermore, as the fiber content increased, microscopic analyses revealed a weakening of the bond between the fibers and the rest of the matrix, contributing to the deterioration of the mechanical properties.

Introduction: The visual appeal and distinctiveness of a building’s external appearance can be enhanced by incorporating aesthetically pleasing and structurally coherent components, such as diagrids and external bracings. These components not only contribute to the building’s visual appeal but also communicate its structural logic. The aim of this research is to investigate how architectural surfaces can contribute to a building’s urban identity by integrating visually appealing and structurally sound structural systems.Methods: The research focuses on analyzing and understanding the formal structure, generating diverse patterns, and assessing their impact on stability. The goal is to develop architectural surface components that are both aesthetically pleasing and proficient in their application. The study involves analyzing architectural projects that address surfaces in alignment with structural connections and various connecting and modulating mechanisms. Significant architectural achievements from different historical periods were examined to construct a comprehensive knowledge framework.Results: The research conducted a detailed analytical and descriptive investigation into the intricate mechanisms of form surfaces within Modernity and Deconstruction architecture and their impact on structural relationships. The study revealed that by integrating structural connections and modulating mechanisms, it is possible to create architectural surface components that enhance a building’s visual appeal, artistic expression, and urban identity while maintaining structural stability and balance.Conclusion: The research concludes that integrating structural connections and modulating mechanisms into architectural surface components can significantly enhance a building’s visual appeal, artistic expression, and urban identity. By developing aesthetically pleasing and structurally sound elements, such as diagrids and external bracings, architects can create buildings that not only communicate their structural logic but also contribute to the overall urban fabric. This study provides valuable insights for architects and designers seeking to enhance the visual and structural qualities of their buildings.

The construction sector in the Kingdom of Saudi Arabia has shown notable growth and progress as seen by the transformation of outdated neighborhoods into modern smart infrastructure that aligns with the 2030 vision of the nation. As a result of this development trend, which is led by the Jeddah region, many older buildings are being demolished, and a significant amount of concrete is being produced. Utilizing recycled aggregates from construction and demolition waste has been recognized as an effective approach to addressing the current environmental problems that our world faces. An appropriate process of treatment techniques must be incorporated into the production of recycled aggregate in order to enhance its properties and optimize its use. The purpose of this study is to determine the potential benefits of an alkaline Ca(OH)₂ activated by fly ash Class F (FA_F) for various concrete mixes composed using recycled concrete aggregate (RCA). Seven mixes were developed to determine the effects of several factors on the properties of recycled concrete aggregate (RCA), including the type of recycled aggregate, the activator used, and the impact of the filler material. The study assessed how different forms of recycled aggregate affected physical characteristics. The compressive strength, flexural strength, indirect tensile strength, and pull-out strength of the concrete mixes was measured. The aggregate water absorption of Jeddah concrete aggregate (JRCA) and variable concrete aggregate (VRCA) was evaluated. Activated JRCA water absorption drops to 1.7% while inactivated JRCA water absorption was 3.95%. The AIV values of JRCA rise to 18.4 while the AIV for NA is 13. The same trend complies with the findings, which demonstrated that the strength performance and other characteristics of the various concrete mixes under study were significantly impacted by the type of recycled aggregate utilized and the mix design. Among these, Jeddah recycled concrete aggregate (JRCA) showed promising results that could lead to a wider use of (JRCA) in civil engineering applications.

Concrete structures in marine environments face significant degradation due to reinforcement corrosion caused by chloride ingress and sulfate attack. Poor construction quality, inadequate standards, and suboptimal design can further accelerate deterioration. Non-destructive testing (NDT) has proven valuable for durability assessment, yet its application remains limited due to the complex microstructural characteristics of concrete. This study establishes a comprehensive procedure for evaluating precast concrete degradation in marine environments using multiple characterization techniques. Two precast concrete elements with different cement types, CEM II A-L 42.5R and CEM I 42.5 R/SR, were analyzed through compressive strength tests, open porosity measurements, mercury intrusion porosimetry (MIP), ultrasonic wave transmission, and scanning electron microscopy (SEM). The results indicate that CEM I 42.5 R/SR exhibits superior compressive strength and lower porosity, making it more durable and suitable for load-bearing applications. Higher ultrasonic pulse velocity (UPV) further confirms its resilience. In contrast, CEM II A-L 42.5R shows lower mechanical performance and greater susceptibility to marine-induced degradation. Over time, pore size distribution shifts, potentially compromising mechanical integrity. SEM analysis reveals gypsum and brucite formation in degraded regions, demonstrating microstructural changes due to seawater exposure. A strong negative correlation between porosity and UPV underscores the detrimental effect of increased porosity on material density and structural stability. This study highlights the effectiveness of UPV and porosity analysis as reliable NDT techniques for assessing concrete deterioration. The strong correlation between UPV and porosity trends suggests that UPV serves as an early indicator of durability loss, enabling timely maintenance interventions. These findings provide valuable insights into material selection for enhanced structural performance in marine environments and emphasize the role of NDT in long-term structural health monitoring.