Geopolymers are inorganic amorphous aluminosilicate materials, which can be produced by the alkali activation of materials with high aluminum and silicon content. In this research, we prepared geopolymer samples obtained from construction and demolition (C&D) waste materials (brick powder and concrete powder), as well as industrial waste material (aluminum dross), and we investigated them using different test methods. Density, particle size distribution and chemical elemental composition were determined on the dried powdered waste materials, and microstructural observations were also made using a scanning electron microscope (SEM) technique. To prepare the geopolymer sample mixtures of sodium-hydroxide and sodium silicate, we used an alkali activator solution at different concentrations (4 M, 8 M and 12 M). We used Fourier Transformation Infrared Spectroscopy (FTIR) to reveal new phases in geopolymer samples. Compression strength was determined after 7 days and after 28 days. In the cases when aluminum dross was used, a gas-forming reaction took place in the geopolymer pastes; therefore, foamed geopolymer was produced. According to these results, the used C&D and industrial wastes may be potential raw materials which could be used to prepare geopolymers.

Ceramics reinforced with carbon and silicon carbide particles are of great importance in the field of technical ceramics and ceramic composites. In this research, the possibilities of producing advanced ceramics from traditional, relatively inexpensive materials were studied. The authors have successfully developed mullite ceramic materials reinforced with carbon particles using kaolinite powder and sawdust. Powder mixtures with different compositions were prepared in a planetary ball mill using silica balls. The produced mixtures were compacted in a 100 kN pull-press to produce pellets using a pressure of 140 MPa. The prepared specimens were sintered in a laboratory chamber kiln under oxygen deficient conditions at 1250°C. After sintering of the specimens, considerable amounts of carbon content were incorporated into the material structure of produced ceramics, which were confirmed by energy-dispersive X-ray analysis. Using 10-20 m% sawdust in the mixtures, the carbon (C) content of sintered specimens was found to be more than 8 m%.

Asphalt industry finds itself battling ongoing economic difficulties and an urge to achieve a more sustainable development and growth. it means constant searching is needed for alternative materials and possibilities to use recycled and processed waste materials in asphalt mixes as long as an expected level of performance and durability is provided. Aluminium dross is a recyclable by-product of the casting process of melted aluminium. in this study an attempt was made to reveal the potentials of using aluminium dross as filler for asphalt wearing course mixes. During the research, filler fractions (d<0.063 mm) were prepared by milling and microstructural tests were conducted both on the alternative and control filler for a better understanding of the materials and their composition. the effect of replacing limestone filler with aluminium dross filler on the performance of asphalt mixes was analysed by performance-based and performance related asphalt mechanical tests according to common standards. in the paper, the properties of fillers and various mechanical test results are presented and by interpreting the tests and results final conclusions are presented regarding the use of aluminium dross as filler in asphalt mixes. keywords: asphalt, aluminium dross, filler, rheology, stiffness kulcsszavak: aszfalt, alumínium salak, töltőanyag, reológia, merevség member of the member of the Hungarian scientific Association for transport bella UDvarDi, bSc Graduated in 2017 as material engineer, Bsc. currently working on her msc diploma work.

Lightweight concrete has been known all around the world for decades. As a masonry material, there is an advantage: it has sufficient mechanical strength despite of its light weight. This research focuses on the production of recycled concrete based lightweight geopolymer concrete samples using glass foam aggregates. During the research geopolymer and concrete samples were made and finally their properties were investigated and compared. In the research work an alkaline silicate reaction (ASR) was also studied on the glass foam lightweight aggregates, which is very important for concrete failure. Material structural and morphological tests were obtained by scanning electron microscopy (SEM) to characterize the geopolymer concrete samples. Compressive strength of lightweight concrete and lightweight geopolymer was determined at the age of 7 days. Glass foam is suitable for use as a lightweight aggregates for workability. Based on the 7 days compressive strength results no crust typical of the ASR reaction was detected on the surface of the mixtures.

Aluminum dross is a recyclable by-product of the aluminum manufacturing process. Since the use of aluminum alloys increased in large quantities, which cause a significant amount of aluminum dross produced, therefore, the need for alternative solutions are also increased. The goal of this study is to investigate the utilization possibility of dross as an alternative asphalt filler. During the research aluminum dross and limestone (as reference material), which is well-known filler in asphalt technology, were investigated. Different tests were done on the samples: specific gravity, particle size distribution, BET specific surface area and Rigden voids were determined on the fillers. Scanning electron microscope was used to characterize the morphological features of fillers. To reveal the affinity of fillers to bitumen hydrophilic/hydrophobic properties and oil adsorption ability were also investigated. These examinations help to better to understand the interaction between fillers and binder material. With the use of fillers asphalt mixtures and specimens were also prepared for stiffness tests and asphalt cracking temperature tests. The results show a good correlation between dross and limestone fillers, therefore aluminum dross may be an alternative to partly substitute limestone filler.