Sürdürülebilir Kalkınma Amaçları
Yayınlar
- MakaleAçık Erişim2026The effect of mine waste ratio and curing duration on the mechanical properties of ground granulated blast furnace slag-based geopolymer mortars
Aksüt, Yavuz Selim; Nas, Evin; Sünnetçi, Kadir; Kaya, Yusuf
This study investigates the mechanical and microstructural behavior of ground granulated blast furnace slag (GGBFS)-based geopolymer mortars in which mining waste (MW) was used as a partial binder replacement (0–30%) under ambient water curing for 7–90 days. Increasing MW content reduced workability and slightly prolonged setting due to its coarser and less reactive characteristics. Mechanical performance improved with curing time and mixtures with moderate MW levels achieved the best strength and microstructural densification. Water absorption and porosity decreased with age, reflecting progressive gel formation. Scanning electron microscope–X-ray diffraction (SEM-XRD) analyses verified matrix densification and enhanced gel development at intermediate MW ratios. Overall, the findings show that controlled MW incorporation can optimize the balance between strength, pore structure and sustainability, enabling ambient cured GGBFS-based geopolymers without thermal curing. The study provides new insights by using MW as a binder phase replacement while preserving precursor chemistry, a rarely explored approach.
- MakaleYalnız künye2014Assessing the Impacts of Seasonal Variations on Predicting Leachate Generation in Gumushane Open Dump Using Water Balance Method
Nas, Salim Serkan; Nas, Evin
Leachate quality varies depending on many factors such as the depth and the content of solid waste, seasonal variations in solid waste, and the duration of storage of solid waste; design and operation of storage space; geological and hydrogeological characteristics of storage area; and environmental interaction of leachate, which affect each other. One of the two major sources of leachate is the moisture content of the waste stored and the other is the mass of water entering the storage area from outside. A major part of the mass of water entering the storage area from outside is the infiltration of rain water through the storage area. The purpose of this study is to assess the seasonal variation in leachate of Gumushane (Central) open dump area using the 'water balance method' for the determination of the factors affecting the seasonal variation in leachate of landfill, which particularly holds a higher risk of contaminating the environment. In addition, some of the measures to be taken in solid waste storage areas in order to minimize the mass of leachate are presented.
- MakaleAçık Erişim2009Water quality modeling and dissolved oxygen balance in streams: A point source Streeter-Phelps application in the case of the Harsit stream
Nas, S. Serkan; Nas, Evin
The Harsit Stream flowing into the Black Sea is an important watershed in the northeastern part of Turkey. The monthly averages of dissolved oxygen, carbonaceous biochemical oxygen demand, temperature, pH, total suspended solids, total phosphorus and total nitrogen were obtained for the water samples taken from the Tekke, Akcakale and Haciemin sites of the Harsit Stream. Water quality parameters were analyzed and evaluated according to the WHO standards and the Turkish Water Pollution Control Regulation. Initially, the variations in the dissolved oxygen profile were determined from dissolved oxygen, temperature and carbonaceous biochemical oxygen demand measurements by using the point source Streeter-Phelps equation. Critical dissolved oxygen deficit values were calculated for the monthly average from January-December 2005, which are below the limit value (4 mg L-1) excluding April (7.26 mg L-1) and May (5.98 mg L-1) in the Harsit Stream, resulting in it having second class water quality in terms of dissolved oxygen concentration, temperature, pH and biochemical oxygen demand. It is also seen that the minimum dissolved oxygen limit value (8 mg L-1), which is a desired quantity for drinking water, is under the limit value for all months in the case of the water mixture. In particular, during the summer months, the consumption speed of oxygen is greater than the production speed of oxygen with increasing temperature and decreasing discharge, and negative values (anoxia) of dissolved oxygen sag are seen. These situations call for significant precautions and treatment criteria.
- MakaleYalnız künye2008Laboratory study of expanded polystyrene (EPS) geofoam used with expansive soils
Ikizler, S. Banu; Aytekin, Mustafa; Nas, Evin
The reduction of transmitted lateral swelling pressures on retaining structures constructed in expansive soils is investigated. Swelling pressures will develop if the soil is not allowed to swell freely. The magnitude of swelling pressure depends on the degree of expansion permitted. When a little soil expansion is allowed, the swelling pressure may be decreased considerably relative to the case of no expansion. This study examines the role of expanded polystyrene (EPS) geofoam in accommodating soil expansion and hence reducing swelling pressures on adjacent structures. Several hypothetical cases are presented whereby reductions on the transmitted lateral pressures due to expansive soils are examined for different thickness of EPS geofoam.