In this study, brass (Cu/Zn) reinforced polymer composites with different proportions of brass powders were fabricated. Different types of nuclear shielding parameters such as mass and linear attenuation coefficients, radiation protection efficiency, half and tenth value layers, and effective atomic number values were determined experimentally and theoretically in the energy range of 0.060–1.408 MeV in terms of gamma-ray shielding capabilities of fabricated polymer composites. A high Purity Germanium detector (HPGe) in conjunction with a Multi-Channel Analyzer (MCA) and twenty-two characteristic gamma-ray energies have been used in the experimental phase. In addition, the exposure and energy absorption buildup factors of reinforced Cu/Zn composites were calculated, and relative dose distribution values were computed to verify them. Proton mass stopping power (Ψ_P), proton projected range (Φ_P), alpha mass stopping power (Ψ_A), and alpha projected range (Φ_A) parameters, which indicate the interactions of the produced composites with charged particle radiation, were investigated. Fast neutron removal cross-section (Σ_R) results were determined to give an idea in terms of neutron shielding. According to the obtained results, it is reported that the CuZn20 coded sample’s ability to attenuate gamma-ray and charged particle radiation is more efficient than that of other prepared composites. A CuZn05 coded sample was found to be more suitable for neutron shielding capability.

The use of recycled aggregate (RA) instead of natural aggregate (NA) in concrete is necessary for environmental protection and the effective utilization of resources. The addition of recycled aggregates in concrete increases shrinkage, porosity and decreases the mechanical properties compared to that of normal concrete. This study was aimed at investigating how the addition of various proportions of polypropylene and steel fiber affect the mechanical properties of recycled aggregate concrete (RAC). The natural coarse aggregates (NCAs) used in the production of normal concrete (NC) were replaced in 30% and 50% proportions by recycled coarse aggregates (RCAs) obtained from the demolished buildings. In this case, a polypropylene fiber (PF) content of 0.1% and steel fiber (SF) 1% and 2% volume fractions were used, along with hybrid fibers-a combination of the two. While the material performance of RAC compared to NC is analyzed by reviewing existing published literature, it is not evident what the use of RCAs and hybrid fibers have on the mechanical properties of concrete. The results showed that the compressive strength, flexural strength and impcat resistance of RAC were reduced as the percentage of RCAs increased. It was observed that the compressive strength was increased with the addition of 1% steel fiber in the RAC. The flexural and impact performance of steel fiber-reinforced concrete (Specimens NC and RAC) was increased as the volume fractions of steel fiber increased. The hybrid fiber reinforced concretes showed the best results in their mechanical performance of all the concrete groups.

The electrical resistivity is an essential parameter describing materials' capacity to convey electric current. Normal cementitious materials display high estimation of the electrical resistivity because of their insulating nature. However, the high electrical resistivity of concrete can be reduced by a sufficient amount of electrically conductive admixture. Such an improvement is advantageous in self-sensing or self-heating concrete design. In this study, the effects of metal additives on the electrical resistivity of hardening cement paste were investigated. In the experiments, two different types of metal admixtures; copper powder and iron powder were used. Hybrid composition of copper and iron were also considered for comparisons of the electrical resistivity. A water to binder ratio of 0.35 was used. The metal powders were used in the mixtures by replacing the cement in ratio of 0%, 5%, 10%, 15% and 20% by weight. The total binder content (cement and metal additives) was always the same in the experiments. The measurements were carried out at room temperature by using two-electrode- AC method. The test results indicate that the metal cement composites with 20% of cement weight improved the lower electrical resistivity of the cement paste than plain cement paste. In addition, composites with copper powders had less electrical resistivity than those with iron powders. The reduction of electrical resistivity with an increase of metal content was steady for when of using hybrid composites better than when using metal powders alone. The Different frequency options 1 kHz, 10 kHz and 100 kHz were used to investigate the effect of impedance-frequency and phase angle-frequency of a sample test using the LCR meter. The highest current frequency available on the LCR meter, 100 kHz, was chosen to be used as the applied current frequency in all of the experiments which exhibit much lower phase angle values that can cancel the effect of change in electrical resistivity measurements.

The world's largest boron deposits are in Turkey, Russia, and the U.S.A. Türkiye holds about 73% of the world's reserves of oil. The tincal mineral accounts for approximately 25.3% of Türkiye's boron reserves. Annually, around 900,000 tons of boron-derived waste are produced to obtain 1 million tons of borax pentahydrate from the tincal mine. This waste is stored in pools, causing considerable environmental issues. This study investigates the potential use of tincal waste, an environmental problem, in cement and concrete applications. Tincal waste (T.W.) was utilized to produce geopolymer mortar. Geopolymer samples were created by replacing ground blast furnace slag (G.B.F.S.) with 10%, 20%, 30%, and 40% tincal waste (T.W.) by weight. The mixture samples were cured at room temperature and 60 °C. After curing, the samples were exposed to high temperatures of 200 °C, 400 °C, and 600 °C. The samples' unit weight, compressive strength, ultrasonic pulse velocity (U.P.V.), and mass loss values were measured. A mathematical model was also developed to describe the relationship between compressive strength and U.P.V. before and after high temperatures. The samples underwent Fourier Transform Infrared Spectroscopy (FTIR) microstructural analysis. The results showed that using up to 20% T.W. enhanced the properties of the samples before and after high-temperature exposure. A strong correlation was found between compressive strength and U.P.V. These findings suggest that T.W. has potential as a novel material for use in geopolymer technology.

Kendiliğinden yerleşen beton, kendi ağırlığı ile yerleşme yeteneğine sahip, sıkıştırma ve yerleştirme için vibrasyon gerektirmeyen bir betondur. Geleneksel beton ile karşılaştırdığımızda minimum işçilik gerektirmesi, ekonomik olması, hızlı uygulanması ve sık donatı arasında ayrışma oluşmadan kalıp içerisini kolaylıkla doldurabilmesi önemli avantajlarıdır. Karışım dizaynı ve üretimi özel bir hassasiyet gerektirmektedir. Bu çalışmada su çimento oranı sabit tutularak farklı oranlarda uçucu kül ilavesi ile elde edilen kendiliğinden yerleşen betonlar için erken yaşta ön ısıtmanın, beton hidratasyonuna etkisinin belirlenmesi amaçlanmaktadır. Üretilen numunelerde, bir grupta 28 gün boyunca su küründe (ön ısıtmasız) bekletilirken diğer grup ise ön ısıtma (1 gün boyunca 75℃) etkisinde bırakılmıştır. Elde edilen numunelere Kendiliğinden yerleşen beton taze beton deneyleri ve sertleşmiş beton mekanik deneyleri uygulanmıştır. Numunelerde birim ağırlık, basınç dayanımı, eğilmede çekme dayanımı ve yarmada çekme dayanımı ölçülmüştür. Eğilmede çekme dayanımı deneyinde her 2 grupta en iyi sonuç %30 uçucu kül katkısı ile elde edilirken yarmada çekme dayanımı deneyinde de en iyi sonuç %30 uçucu kül katkılı ön ısıtmasız numunelerde gözlemlenmiştir. Elde edilen sonuçlara göre ön ısıtmasız numunelerin basınç dayanımı, ön ısıtmalı numunelerden daha yüksek olduğu görülmüştür. Ek olarak uçucu küllü betonların ön ısıtmaya maruz kaldıklarında olumlu etki gösterebileceği bu çalışma ile belirlenmiştir.