Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 57 11 2026 02 19 Advancements, Challenges, and Future Prospects of Structural Lightweight Concrete: Emphasizing the Role of Fly Ash in Sustainable Construction Advancements, Challenges, and Future Prospects of Structural Lightweight Concrete: Emphasizing the Role of Fly Ash in Sustainable Construction 1981 2010 5991 10.22060/ceej.2026.24576.8326 FA Saeed Vahdani Master of Science in Civil Engineering, Binaloud Institute of Higher Education, Mashhad, Iran 0009-0004-0683-6148 Shahram Pourakbar b Assistant Professor, Department of Civil Engineering, Binaloud Institute of Higher Education, Mashhad, Iran 0000-0003-2342-9582 Armin Hatami Rad Master’s Student in Civil Engineering, Islamic Azad University, Mashhad Branch, Mashhad, Iran 0009-0001-4709-8012 Jafar Najafizadeh Assistant Professor, Department of Civil Engineering, Islamic Azad University, Mashhad Branch, Mashhad, Iran 0009-0005-8007-2104 Journal Article 2025 08 15 Structural lightweight concrete (SLC), as one of the modern and efficient materials in contemporary construction, has attracted increasing attention due to its reduced unit weight, enhanced thermal performance, and improved structural efficiency. In recent decades, various types of SLC have been developed through the utilization of natural and artificial lightweight aggregates, cellular and foamed concretes, fiber-reinforced systems, nanomaterials, and recycled materials. Among these, the incorporation of fly ash—one of the most significant industrial by-products—has played a substantial role in improving the mechanical properties, durability, and environmental performance of lightweight concrete. Studies indicate that integrating advanced technologies with recycled materials can open new horizons for optimizing performance and reducing construction costs. Furthermore, forward-looking assessments suggest that expanding the application of fly ash, alongside the establishment of unified standards, can pave the way for sustainable development in large-scale infrastructure projects. This review article adopts a comprehensive, critical, and future-oriented perspective to examine recent advancements, technical and practical challenges, and the potential capacities of various types of structural lightweight concrete. Particular emphasis is placed on the pivotal role of fly ash in enhancing performance and contributing to sustainability in this field. Finally, existing research gaps, proposed future directions, and the necessity of developing comprehensive standards are highlighted. Structural lightweight concrete (SLC), as one of the modern and efficient materials in contemporary construction, has attracted increasing attention due to its reduced unit weight, enhanced thermal performance, and improved structural efficiency. In recent decades, various types of SLC have been developed through the utilization of natural and artificial lightweight aggregates, cellular and foamed concretes, fiber-reinforced systems, nanomaterials, and recycled materials. Among these, the incorporation of fly ash—one of the most significant industrial by-products—has played a substantial role in improving the mechanical properties, durability, and environmental performance of lightweight concrete. Studies indicate that integrating advanced technologies with recycled materials can open new horizons for optimizing performance and reducing construction costs. Furthermore, forward-looking assessments suggest that expanding the application of fly ash, alongside the establishment of unified standards, can pave the way for sustainable development in large-scale infrastructure projects. This review article adopts a comprehensive, critical, and future-oriented perspective to examine recent advancements, technical and practical challenges, and the potential capacities of various types of structural lightweight concrete. Particular emphasis is placed on the pivotal role of fly ash in enhancing performance and contributing to sustainability in this field. Finally, existing research gaps, proposed future directions, and the necessity of developing comprehensive standards are highlighted. https://ceej.aut.ac.ir/article_5991_c0356641f421b381e475776b602a5da8.pdf