Yazar "Sagir, Mehmet Akif" seçeneğine göre listele

Listeleniyor 1 - 2 / 2
  • Küçük Resim Yok
    Öğe
    Effect of binder dosage and the use of waste rubber fiber on the mechanical and durability performance of geopolymer concrete
    (Elsevier, 2022) Yolcu, Abdurrahman; Karakoc, Mehmet Burhan; Ekinci, Enes; Ozcan, Ahmet; Sagir, Mehmet Akif
    This paper was designed to find solutions to the fact that the availability of natural aggregates in accordance with the standards used in concrete is gradually decreasing, the environmental problems caused by cement threaten our future, and the recycling of used tire waste is very difficult. The effects of three different binder dosages (300, 400 and 500 kg/m(3)) on the mechanical and durability properties of geopolymer concrete (GPC) samples were investigated in binder contents consisting of 98% granulated blast furnace slag (GBFS) and 2% nano silica. As for the aggregate composition, natural sand was used as the fine aggregate, while the waste rubber fibers (WRF) were substituted in different proportions (0%, 5%, 10% and 15%) of the coarse aggregate by volume. Following the solid part was obtained as described, the alkaline activation of GPC specimens was provided using a 12 M NaOH solution. At the end of 28-day curing period, compressive strength, flexural strength, splitting tensile strength, impact resistance, capillary permeability and elevated temperature performance properties were investigated in detail and the results obtained from the mentioned tests were also confirmed by microstructural analysis. Experimental findings revealed that the increase in binder dosage resulted in significant increases in all of the mechanical properties, and it was speculated that this was due to the formation of a denser and more compact microstructure compared to their counterparts produced using lower binder dosage. Besides the negative effects of WRF usage on compressive strength and resistance of elevated temperature, the other performance criteria such as flexural strength, impact resistance and splitting tensile strength values of GPC samples significantly improved with the usage of WRF. As a result, experimental findings demonstrated that the usage of waste rubber fibers in the production of GPC was advantageous in terms of some mechanical and durability properties.
  • Küçük Resim Yok
    Öğe
    Effect of silica fume and waste rubber on the performance of slag-based geopolymer mortars under high temperatures
    (Ernst & Sohn, 2023) Sagir, Mehmet Akif; Karakoc, Mehmet Burhan; Ozcan, Ahmet; Ekinci, Enes; Yolcu, Abdurrahman
    In this study, the fire resistance of slag-based geopolymer mortars was investi-gated and the effect of silica fume (SF) and waste rubber (WR) on this resistance was determined. In slag-based geopolymer mortars activated using 12M NaOH solution, 0%, 5%, and 10% by weight SF was substituted for slag; 0%, 5%, 10%, and 15% WR by volume were substituted for fine aggregate. The samples that completed the curing period were exposed to temperatures of 250 degrees C, 500 degrees C, and 750 degrees C for 1 h, and the mechanical (compressive, flexural and splitting tensile strengths, and impact resistance), physical (weight change and sorptivity) and microstructure (scanning electron microscopy [SEM] and energy dispersive spectroscopy [EDS]) properties of these samples were examined. The compres-sive strengths of the samples without WR were between 48.10 and 60.97 MPa, and the samples without SF were between 28.52 and 48.10 MPa. Strength losses at 750 degrees C were between 51.5% and 73.5%. As the SF substitution increased, the samples' mechanical and physical properties improved, whereas as the WR sub-stitution increased, the samples' mechanical and physical properties declined. While the SF substitution had a positive effect on the fire resistance of the sam -ples, the WR substitution had a negative effect. It is thought that the choice of geopolymer binder as a binder in the mortar and the use of waste tires as aggre-gate contribute to the literature in terms of both preventing environmental pollution and ensuring the recycling of these materials.