Browsing by Author "Salih Taner Yildirim"

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    Effect of glass and nylon fibers on drying shrinkage of alkali activated blast furnace slag mortars
    (Taylor & Francis, 2024-08-13) Nahla Hilal; Salih Taner Yildirim; Ahmet Kaan Yildirim
    The environmental consequences of Portland cement (PC) manufacturing have prompted the exploration of alternative binders, such as the alkali activation of blast furnace slag (BFS), which is generated as a byproduct during the extraction of iron. While alkali-activated blast furnace slag (AAS) binders have some benefits over regular PC binders, they also suffer from disadvantages such as significant drying shrinkage. The study investigated the impact of Na dosage and curing conditions on alkali-activated blast fur nace slag mortar (AASM). The consistency of the specimens was tested for fresh, hardened properties, and was conducted. The optimum Na dosage and curing conditions were selected. In the second stage, 0.1% and 0.2% glass and nylon fibers were added to the selected optimum mortar. Consistency, fresh, mechanical, and durability properties tests were con ducted on the fiber mortars. The results showed that increasing the Na content increased the compressive and flexural strengths of AASM speci mens. Thermal curing provided high compressive and flexural strengths, whereas fiber addition reduced water absorption and drying shrinkage. The drying shrinkage value was reduced by 26.82 % for AASM specimens with 0.2 % nylon fibers by volume compared to AASM without fibers.
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    The influence of waste polypropylene fibers on the behavior of sustainable reinforced concrete beams
    (John Wiley & Sons, 2025-02-04) Nahla Hilal; Sulaiman Nayef Ahmed; Ayad S. Aadi; Mohammed Nawar; Salih Taner Yildirim; Nadhim Hamah Sor
    Plastic waste has recently become one of the most important environmental issues. Plastic fibers in concrete provide a long-term solution to plastic waste management. Concrete is a rigid material and has superior compressive strength but has poor tensile strength. Using waste plastic fibers in concrete can address its brittleness and low tensile strength. In this study, waste polypropylene fiber (WPF) prepared from discarded plastic tapes in reinforced concrete (RC) beams was used. WPF of 5 mm width was added to the concrete at a volumetric percentage of 1%. The fibers were added at different lengths (50, 70, and 90 mm) individually, and then all lengths were mixed randomly. This study provides the results of laboratory tests conducted to evaluate the mechanical properties of the WPF-RC. Additionally, a comparison of RC beams with the same percentage of reinforcement but varying lengths of WPF in the tensile zone was provided. The criteria for the flexural test were determining the ultimate load, the yield, and the first cracking as well as the deflections associated with these loads. Evaluations of the energy absorption index, ductility, and failure modes were also carried out. The WPF enhanced the ultimate load by 5%, the deflection at the ultimate load by 33.26%, and the splitting tensile strength by 51.47% for the concrete. Additionally, the load– deflection relationships demonstrated that concrete beams reinforced with WPF tend to deflect more before failing. The energy absorption index capacity is increased by 94.36% and ductility by 25.83% for the beam reinforced with 1% WPF, mixed randomly at mixing randomly lengths. This possible enhancement of RC beam performance based on the WPF can promote the use of sustainable concrete in many structural applications based on the WPF.