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    Enhancing Strength and Ductility of Rubberized Concrete Using Low-Cost Glass Jackets
    (2026-04-01)
    Saingam, Panumas
    ;
    Noman, Muhammad
    ;
    Chatveera, Burachat
    ;
    Sua-Iam, Gritsada
    ;
    Mehmood, Tahir
    This study examines the compressive behavior and analytical modelling of natural and rubberized concretes (RuC) confined with low-cost glass chopped-strand mat (GCSM) jackets. A total of forty-two cylindrical specimens were tested under axial compression to assess the influence of rubber particle size, confinement configuration, and the number of GCSM layers. The RuC mixes were prepared by replacing 20% of fine aggregate by volume with crumb rubber of two size fractions: coarse (2.0 mm, retained on #10 sieve) and fine (0.425 mm, retained on #40 sieve). Both full- and strip-wrapping schemes were applied using two, four, and six layers of GCSM. The results demonstrated that GCSM jackets significantly enhanced the mechanical performance of both NAC and RuC specimens. Full wrapping provided the highest confinement efficiency, increasing compressive strength by up to 115% for NAC and 90% for RuC, while the ultimate axial strain increased by more than 1300% compared with unconfined specimens. Strip wrapping also improved performance, producing strength gains of 25–45% and strain increases of 250–500%. Analytical stress–strain models were developed through regression analysis, showing strong correlation with the experimental results (R<sup>2</sup> = 0.80–0.99). The proposed GCSM jacket system demonstrates high potential as a sustainable and economical alternative for strengthening and retrofitting rubberized concretes, offering improved ductility and energy absorption while supporting circular material utilization. It is noted that the confinement ratio, size of rubberized aggregates, and their percentage replacement of rubberized aggregates should be consistent with the values used in this work in order to use the proposed analytical expressions.
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    Item type:Publication,
    Eco-Friendly Structural Solutions: The Synergy of Waste Rubber and Hemp Fibers in Sustainable Concrete Design
    (2026-01-01)
    Thansirichaisree, Phromphat
    ;
    Mohamad, Hisham
    ;
    Chaimahawan, Preeda
    ;
    Hussain, Qudeer
    ;
    Jirasakjamroonsri, Amornthep
    The growing emphasis on sustainable construction has encouraged the integration of recycled and renewable materials into structural concrete. This study investigates the axial compressive behavior of rectangular columns incorporating waste-tire rubber as a partial replacement of fine aggregate (5% and 10%) and external confinement using low-cost hemp ropes. A total of twelve specimen configurations, including unconfined and hemp-confined columns with up to three wrapping layers, were tested under monotonic axial compression. The results show that rubber inclusion reduces initial stiffness and peak strength by up to 46%, yet significantly enhances deformability. Hemp-rope confinement effectively compensates for strength loss, increasing compressive strength by up to 53% and ultimate strain by over 500%, with more pronounced effects in rubberized mixes. Normalized strength and strain trends demonstrate a strong dependence on confinement ratio, particularly for highly deformable concrete. To generalize these behaviors, Popovics-based models were calibrated using nonlinear regression, yielding high predictive accuracy (R<sup>2</sup> = 0.94–0.98) for key parameters including peak stress, peak strain, post-peak modulus, and elastic modulus. The proposed expressions closely reproduce the experimental stress–strain response and provide practical tools for modeling confined conventional and rubberized concrete.
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    Influence of Recycled Plastic Incorporation as Coarse Aggregates on Concrete Properties
    (2023-04-01)
    Ali, Khawar
    ;
    Saingam, Panumas
    ;
    Qureshi, Muhammad Irshad
    ;
    Saleem, Shahzad
    ;
    Nawaz, Adnan
    Plastic waste has increased significantly in recent years as a result of fast population growth and urbanization. Studies on the incorporation of plastic aggregates as a substitution for natural aggregates in concrete are needed to successfully reduce both adverse environmental impact and the depletion of natural resources. The objective of this research was to investigate the use of plastic as a partial substitution for natural coarse aggregates in concrete. For this purpose, seven concrete mixes were produced using 0, 10, 15, and 20% plastic coarse aggregates to replace natural aggregates with and without silica fume of similar replacement levels with cement. Fresh density, workability, compressive strength, splitting tensile strength, stress–strain response, and Poisson’s ratio were observed to study the fresh as well as hardened properties of concrete mixtures. Indoor and outdoor thermal performance and thermo-gravimetric analysis were also investigated. The results revealed that the plastic aggregates’ incorporation improved the workability of concrete; however, it negatively influenced the fresh density and mechanical properties of concrete. The compressive and tensile strengths of plastic aggregate concrete without silica fume were reduced by 32 and 33%, respectively. The reduction in strength could be associated with the smooth texture of plastic aggregates. The addition of silica fume with plastic aggregates resulted in denser concrete and improved mechanical properties. In general, the performance of plastic aggregates as a partial replacement for natural aggregates was satisfactory, which suggests their possible use to produce eco-friendlier concrete.