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Open research questions in Recycled Aggregate Concrete Performance

56 unresolved questions extracted from the limitations and future-work sections of 281 Recycled Aggregate Concrete Performance papers in our library. Each links back to the study that raised it.

What the literature leaves open

  • The study only considers the mechanical properties of recycled aggregate concrete under impact loading. The model is validated through experimental results, but further validation is needed. The study does not investigate the long-term durability of recycled aggregate concrete.

    A New Experiment-Based Numerical Model for Simulating the Mesoscopic Damage of Recycled Aggregate Concrete Under Impact Loading · 2026 · DOI

  • Further validation of the new numerical model is needed. The study's findings can inform the development of new standards for recycled aggregate concrete. The long-term durability of recycled aggregate concrete needs to be investigated.

    A New Experiment-Based Numerical Model for Simulating the Mesoscopic Damage of Recycled Aggregate Concrete Under Impact Loading · 2026 · DOI

  • Further research is needed to investigate the effects of other parameters on the axial compressive behaviour of RBCA concrete. The development of more comprehensive stress-strain models for confined RBCA concrete is needed.

    Axial Compressive Behaviour of Steel Tube Confined Recycled Brick–Concrete Aggregate Concrete · 2026 · DOI

  • There is a lack of understanding of the mechanical properties of RBCA concrete. There is a need to develop sustainable construction materials and practices.

    Axial Compressive Behaviour of Steel Tube Confined Recycled Brick–Concrete Aggregate Concrete · 2026 · DOI

  • The porosity and weaker bond between aggregate and paste in RCA concrete. The limitation of current studies in determining the minimum amount of fibers required. The need to develop guidelines for the use of RCA concrete in construction projects.

    Performance Evaluation of Recycled Aggregate Concrete Enhanced with Hooked Steel Fibers: Fresh and Hardened Properties · 2026 · DOI

  • The stability of transportation infrastructure in permafrost regions is threatened by warming and engineering disturbance. The use of recycled aggregate concrete in permafrost regions is limited by its low early-age mechanical performance.

    Early-Age Strength Development and Microstructural Mechanisms of CO <sub>2</sub> -Cured Recycled Weathered Limestone Concrete · 2026 · DOI

  • Excessive extraction of natural resources, environmental degradation, and depletion of virgin materials. The construction industry consumes billions of tons of raw materials annually, with aggregate production alone accounting for nearly 7% of total energy consumption. The need for a sustainable approach to pavement construction.

    EVALUATION OF GEOSYNTHETIC-REINFORCED C&D WASTE FOR FLEXIBLE PAVEMENT APPLICATIONS – A SUSTAINABLE APPROACH · 2026 · DOI

  • Construction waste poses environmental challenges. Construction waste poses economic challenges. There is a need for effective waste management policies.

    Compositional analysis and quantification of construction waste from residential building projects · 2026 · DOI

  • The use of recycled aggregates (RA) in structural concrete is limited by adhered mortar, high porosity, and weak interfacial transition zones, which adversely affect durability and mechanical performance.

    Improved performance of recycled aggregate concrete using a combined treatment approach · 2026 · DOI

  • While the study documents that current environmental laws lack C&D-specific provisions, it does not evaluate which existing global C&D waste regulations (from other South/Central Asian contexts or international standards) would be most applicable to Kabul's institutional and economic conditions; research should conduct a comparative regulatory analysis and pilot test an adapted C&D waste management regulation framework.

    Construction and Demolition Waste Management in Kabul, Afghanistan · 2026 · DOI

  • The barrier analysis identifies lack of trained personnel as a significant constraint, yet the paper does not specify what technical competencies or training curricula are required for effective C&D waste sorting and recycling operations; research should define skills requirements and test targeted vocational training interventions for personnel involved in sorting, material processing, and recycling facility management.

    Construction and Demolition Waste Management in Kabul, Afghanistan · 2026 · DOI

  • The use of recycled materials in construction can be challenging due to variability and contamination. The development of sustainable construction materials and practices requires a multidisciplinary approach. There is a need to balance the technical, environmental, and economic feasibility of using recycled materials in construction.

    Impact of Incorporating Recycled Fine Concrete Aggregate and Recycled Concrete Powder in Mortar: Technical and Environmental Impact Assessment · 2026 · DOI

  • There is a lack of research on the technical and environmental feasibility of incorporating fine recycled concrete aggregate and recycled concrete powder in mortar. The existing body of research on recycled materials in construction is limited. There is a need for further studies on the optimal replacement levels of fine recycled concrete aggregate and recycled concrete powder for improved mortar performance.

    Impact of Incorporating Recycled Fine Concrete Aggregate and Recycled Concrete Powder in Mortar: Technical and Environmental Impact Assessment · 2026 · DOI

  • Although the adhered old mortar is recognized as the most distinctive feature of RAC, its bidirectional influence on chloride transport, acting as a preferential transport pathway and a chloride-binding reservoir, has not yet been systematically elucidated.

    Multi-Species Modeling of Chloride Ingress in Heterogenous Recycled Aggregate Concrete: Bidirectional Effects of Old Mortar · 2026 · DOI

  • There is a lack of studies attempting to determine the minimum amount of fibers required to restore different strength properties at specific RCA levels. The current research aims to fill this gap by evaluating various HSF quantities and RCA replacement levels.

    Performance Evaluation of Recycled Aggregate Concrete Enhanced with Hooked Steel Fibers: Fresh and Hardened Properties · 2026 · DOI

  • Further studies on the use of different types of recycled aggregates and their effects on the properties of concrete. Investigations into the long-term durability and performance of recycled aggregate concrete. Development of more advanced methodologies for optimizing the composition of recycled aggregate concrete.

    Mechanical and durability assessment of slag-based recycled aggregate concrete modified with glass fiber and alccofine · 2026 · DOI

  • The lack of studies on the use of multi-component optimization to enhance the performance and durability of recycled aggregate concrete. The need for more sustainable and durable construction materials. The limited understanding of the interactive effects of different materials on the properties of recycled aggregate concrete.

    Mechanical and durability assessment of slag-based recycled aggregate concrete modified with glass fiber and alccofine · 2026 · DOI

  • There is a lack of standardized industry standards for RAC. There is limited construction experience with RAC. There is a need for further research on the long-term durability of RAC.

    The Application of Recycled Aggregate Concrete in Sustainable Civil Engineering · 2026 · DOI

  • There is a lack of understanding of the fire performance of concrete with high recycled aggregate content. The current guidelines for the use of recycled concrete aggregates in construction do not account for their fire performance.

    Experimental Investigations About the Fire Performance of Concrete with High Recycled Aggregate Content (IWCF RILEM 2025) · 2026 · DOI

  • Existing research on the axial compressive performance and size effect of carbon fiber-reinforced polymer (CFRP)-confined recycled aggregate concrete (RAC) short columns mainly relies on macroscopic experimental analysis, lacking research methods capable of reflecting the heterogeneous characteristics of materials and mesoscopic damage evolution mechanisms.

    Size Effect Analysis of Axial Compressive Mechanical Behavior of CFRP-Confined RAC Short Columns Based on a Three-Dimensional Mesoscopic Finite Element Method · 2026 · DOI

  • There is a need for standardization in the production and use of recycled coarse aggregate. There is a need for further research on the economic benefits of using recycled coarse aggregate. There is a need for further research on the environmental impacts of using recycled coarse aggregate.

    Recycling Construction and Demolition Waste Into Coarse Aggregates: A State-of-the-Art Review · 2026 · DOI

  • Investigating the long-term effects of using eggshell powder and recycled fine aggregate in concrete production. Analyzing the economic and environmental benefits of using recycled materials in concrete production. Developing new concrete mix designs that incorporate recycled materials and optimizing their mechanical properties.

    Effect of Utilizing Eggshell Powder and Fine Recycled Aggregate on the Mechanical Properties of Sustainability Concrete · 2026 · DOI

  • The lack of research on the use of eggshell powder and recycled fine aggregate in concrete production. The need for a comprehensive analysis of the effects of combining eggshell powder and recycled fine aggregate on the mechanical properties of sustainability concrete. The limited understanding of the long-term effects of using eggshell powder and recycled fine aggregate in concrete production.

    Effect of Utilizing Eggshell Powder and Fine Recycled Aggregate on the Mechanical Properties of Sustainability Concrete · 2026 · DOI

  • There is a need to investigate the effects of CO2 curing on the mechanical performance of recycled aggregate concrete. There is a lack of understanding of the microstructural mechanisms underlying the enhancements in the concrete’s early-age mechanical performance.

    Early-Age Strength Development and Microstructural Mechanisms of CO <sub>2</sub> -Cured Recycled Weathered Limestone Concrete · 2026 · DOI

  • There is a lack of research on the use of FRCA in self-compacting mortar. The study aims to fill this gap by investigating the effect of FRCA incorporation rates on the properties of self-compacting mortar.

    Effect of fine recycled concrete aggregate incorporation rates on rheological and mechanical properties of self-compacting mortar · 2026 · DOI

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56 open questions have been extracted from the limitations and future-work passages of 281 Recycled Aggregate Concrete Performance papers in our library. Each one below links back to the study that raised it, so you can read the original claim in context.

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