Yazar "Cavus, Murat" seçeneğine göre listele

Listeleniyor 1 - 2 / 2
  • Küçük Resim Yok
    Öğe
    Mechanical, durability and microstructural characteristics of Portland pozzolan cement (PPC) produced with high volume pumice: Green, cleaner and sustainable cement development
    (Elsevier Sci Ltd, 2023) Ulusu, Hayati; Aruntas, Hueseyin Yilmaz; Gultekin, Arzuhan Burcu; Dayi, Mustafa; Cavus, Murat; Kaplan, Gokhan
    Nowadays, it is frequently preferred to use pozzolans instead of clinker to reduce the CO2 emissions that increase with cement production. Because in the future, the release of artificial pozzolans, such as fly ash and blast furnace slag, will decrease. Therefore, the demand for natural pozzolanic cement will increase. This study aimed to produce Portland Pozzolan Cement (PPC) by using pumice instead of clinker up to 40%. The Chemical, physical, mechanical, durability, microstructure, and carbon footprint characteristics of PPCs were investigated experimentally. As the pumice volume in the PPCs increased, the CaO/SiO2 ratio and specific gravity decreased. Due to the hygroscopic moisture of the pumice, its grindability has become difficult. While the 40 mu m sieve residue of PPCs ranges from 0.8 to 1.7%, the sieve residue ratio generally increases as the pumice volume in-creases. The porous structure of pumice led to an increase in Blaine fineness as the replacement ratio increased. The Blaine fineness of PPCs containing 40% pumice rose by about 20% more than the reference cement. The consistency water of PCs varies between 29 and 36%. As the water consistency increased, the setting time of the pastes was prolonged. Initial setting times of PPCs are between 150 and 220 min. If the CaO/SiO2 ratio decreased with the pumice volume, the compression strength of the mortars decreased. While the 28-day compression strength of PPC containing 10% pumice was measured as 36.2 MPa, this value was measured as 21.6 MPa for PPC containing 40% pumice. As the pumice volume increased, the mortars' drying shrinkage and sulfate-induced expansion values decreased significantly. According to the sustainability analysis, the CO2 emissions of cement vary between 518 and 880 kg CO2/t. By using pumice instead of clinker, CO2 emissions of cement can be reduced. In SEM examinations, it was determined that pumice concentrated the microstructure. As a result, it has been determined that eco-friendly cement can be obtained by using 10% and 20% pumice in PPC production.
  • Küçük Resim Yok
    Öğe
    Sustainable lightweight wall blocks from recycled construction waste: The role of diatomite in mechanical ecological and thermal optimization
    (Elsevier Sci Ltd, 2025) Cavus, Murat; Dayi, Mustafa; Aruntas, Huseyin Yilmaz; Kaplan, Gokhan
    This study evaluates the recycling potential of lightweight masonry blocks obtained from construction and demolition waste. The study used waste clay brick (WCB) and waste foam concrete (WFC) as fine aggregates to produce environmentally friendly lightweight masonry blocks. Diatomite, a natural pozzolanic material, was used as an additive in block production by replacing 10 %, 20 % and 30 % cement. The density of the material was reduced by using 6-7 % foam in the block mixtures. The produced samples' physical, mechanical, mineralogical, microscopic and thermal conductivity properties were analyzed. According to the experimental results, the density of the blocks varied between 0.98 and 1.12 g/cm3 , 28-day compressive strength was determined as 2.2-6.3 MPa and thermal conductivity coefficient as 0.15-0.21 W/mK. In mixtures where WCB aggregate was used, strength decreased while density increased; however, blocks produced with WFC aggregate showed higher compressive strength. The addition of diatomite increased the strength in the mixtures with WFC aggregate and decreased the strength in the series with WCB aggregate; however, diatomite significantly reduced the coefficient of thermal conductivity in all series. In SEM analyses, it was observed that the samples with diatomite addition had a more compact structure. XRD analyses revealed that diatomite reacted with calcium hydroxide to reduce the amount of Portlandite and consequently increased the strength. TG-DTA analyses show that diatomite contributes to the pozzolanic reaction. Thanks to the use of 30 % diatomite, carbon emissions and embodied energy in producing lightweight block elements have been reduced by 35-40 %. In addition, the cost of these blocks could be reduced by up to 45 % with 30 % diatomite. In conclusion, this study has demonstrated that WCB and WFC wastes can be used as fine aggregates in lightweight masonry blocks. The study offers a new approach to producing a sustainable building material by solving environmental problems.