Cirkularna ekonomija u službi održivog razvoja građevinskih proizvoda na bazi glina

Pred proizvodnjom tradicionalnih proizvoda na bazi gline postavljaju se brojni izazovi na globalnom nivou. I pored toga, oni predstavljaju jedan od osnovnih materijala sa primenom u građevinarstvu. U radu se predstavljaju moguća poboljšanja u proizvodnji: optimalno korišćenje prirodnih mineralnih resursa, korišćenje otpadnih materijala, smanjenje potrošnje energije i korišćenje zelene energije, smanjenje emisije opasne po zdravlje i životnu sredinu, smanjenje emisije CO2, analiza uticaja proizvoda na životnu sredinu, rekultivacija ležišta i dr. Ključni parametri kod kojih treba obratiti pažnju su vezani za značajan doprinos opekarske industrije globalnoj emisiji CO2, uglavnom zbog energetski intenzivnih procesa proizvodnje i korišćenja neobnovljivih izvora energije. Ključni pravci razvoja obuhvtaju prelazak na „zelenu“ energiju i korišćenje veštačke inteligencije za praćenje i optimizaciju proizvodnje. Ovaj rad daje sveobuhvatan pregled trenutnog stanja opekarske industrije i nudi preporuke za buduća istraživanja i inovacije za promovisanje održivosti životne sredine

Smernice za tretiranje otpada od rušenja i građenja u cilju dobijanja recikliranog agregata, kvalitet dobijenog agregata na bazi izvršenih laboratorijskih ispitivanja

Reciklirani agregat, koji obuhvata otpad od rušenja, renoviranja i samog procesa izgradnje, i u Srbiji polako počinje da dobija na značaju i da pronalazi svoje mesto na tržištu. O tome svedoče sve češći zahtevi za ispitivanja i dokazivanje upotrebljivosti ovog materijala, kao i uspostavljanje određenih zakonskih okvira, koji prepoznaju značaj ove vrste agregata. U radu su dati osnovni preduslovi proizvodnje kvalitetnog recikliranog agregata i iskustva Instituta IMS stečena kroz vršenje laboratorijskih ispitivanja

Investigation of the impact of the magnetic separation technique on the recovery of non-ferrous metals from Pb-Zn smelter slag

This study offers new approach to the non-ferrous metals’ concentration from Pb-Zn slag using a magnetic separation. This technology is more ecological than conventional processes, therefore it may have a substantial influence on the progress of metallurgical slag beneficiation techniques. Physicochemical and mineralogical investigations indicated that Pb-Zn slag is an inhomogeneous with considerable Pb, Zn, Cu, and Ag amounts. Experiments showed that the separated magnetic fraction includes unequal quantities of arsenic, preventing the output from being commercial. Arsenic content was 0.3-32%. Optical and scanning electron microscopy with EDS determined if arsenic can be liberated or easily leached from the resulting material. It was discovered that arsenic is mainly fused with iron-bearing minerals, which are predominantly trapped within amorphous alumino-silicates or intergrowths of alloy grains and glassy phases. This indicates that the produced iron concentrate is viable as a commercial product and in compliance with circularity principles and Green Agenda

External validation of the recently reported drying theory

Even though developed drying theory and Deff-MR curves were successfully used, for modelling the suitable drying regimes of roofing tiles on laboratory and industrial scale during last 15 years, its theoretical contribution as a tool on which all internal moisture mechanisms can be easily registered is still not close enough to the brick and tile companies. The main goal of this paper was to additionally externally validate the developed drying theory and to reveal the universal potential of variable Deff-MR curves for various drying application. The first step was to digitalize the various MR vs – time and MR vs linear shrinkage data taken from the literature. These data were further processed in accordance with the reported drying theory. Deff – MR curves were constructed in the next step. These curves were compared with the originally reported one. The shape of curves was at the first sight similar but after a close look actually all deviation of original data from fitted Deff - MR curves had its theoretical explanation. The transition points of internal mechanisms registered on theoretical Deff – MR curve were revealed on externally taken literature data. It is interesting that this pattern was revealed regardless to the fact that the calculation method for time-dependent Deff coefficient was different. This was reliable external validation proof that that the developed drying theory and Deff-MR have universal theoretical and practical significance

AI-driven models for prediction of ceramic tiles’ properties and detection of the influences: Behavior during shaping and drying

The shaping and drying of ceramics are a critical yet complex process that directly influences ceramic materials’ final properties and performance. Predicting key parameters such as the coefficient of plasticity, mass loss during drying in the air at the critical point, and shaping moisture is essential for optimizing these processes. This study analyzes the dataset of the clays of various chemical compositions to predict and reveal the most important influences on the shaping and drying parameters in producing ceramic tiles. The data are then employed to develop and compare four advanced machine learning models. The models were evaluated using the most important performance metrics such as the coefficient of determination (R²), mean absolute percentage error (MAPE), mean absolute error (MAE), and root mean squared error (RMSE). Extreme Gradient Boosting (Gradient Boosting) emerged as the most reliable model, with 0.9871 R², 0.2672 RMSE, 0.2086 MAE, and 1.61% MAPE. Support vector regression and artificial neural networks also delivered strong performances, while random forest, though competitive, was slightly less accurate. Furthermore, model interpretation methods in machine learning analysis provided valuable validation of the predictive capabilities of the models and the influence of key input features. The advanced machine learning techniques in optimizing ceramic shaping processes offer a robust predictive toolkit for enhancing efficiency, reliability, and sustainability in ceramic materials engineering. It is seen that the Al2O3 levels up to 23% had little effect on plasticity and drying susceptibility, with significant changes occurring above 28%. The critical Fe2O3 content is found between 1.5% and 1.7%, and SiO2 of up to about 62%. The findings of this study offer valuable decision-support tools for ceramic manufacturers, raw material suppliers, and process engineers, enabling more informed material selection, reduced waste, and improved product consistency across the industry

Uticaj drobljene reciklirane gume na otpornost betona na dejstvo mraza

U radu je analizirana mogućnost primene betona sa 2.5%, 5% i 7.5% zapreminske zamene sitnog agregata sa drobljenom recikliranom gumom (CRC – 2.5%, CRC – 5% i CRC – 7.5%), primenjenim vodocementnim odnosima W/C = 0.55, 0.50, 0.45 i 0.40 u odnosu na običan (referentni) beton (OPC) i beton sa hemijskim dodatkom aeranta (AER), sa aspekta primene u svežem betonu koji je praćen kroz vreme od 10, 30 i 60 minuta od momenta dodavanja vode u betonsku mešavinu i dobijenih fizičko-mehaničkih svojstava očvrslog betona. Dat je pregled i analiza aktuelnih istraživanja iz oblasti primene zrna drobljene reciklirane gume, različitih veličina, na osnovu čega je formirana baza podataka pomoću koje je definisan program sopstvenog eksperimentalnog istraživanja. Istraživanje uticaja zapreminske zamene sitnog agregata drobljenom recikliranom gumom je zasnovano na komparativnoj analizi 20 betonskih mešavina u kojima je variran zapreminski sadržaj drobljene gume u vrednostima od 2.5%, 5% i 7.5% kojim je zamenjen deo sitne frakcije agregata. Izvršena su ispitivanja svežeg i očvrslog betona. Kod svih betona praćeno je ponašanje sveže betonske mešavine kroz vreme (nakon 10, 30 i 60 minuta) od momenta dodavanja vode u betonsku mešavinu. Izvršena su ispitivanja svežeg betona: konzistencija metodom sleganja, sadržaj vazduha i zapreminska masa. Na očvrslom betonu izvršena su ispitivanja: zapreminska masa, čvrstoća pri pritisku, vodonepropustljivost, otpornost betona na dejstvo mraza, otpornost betona na dejstvo mraza uz prisustvo soli za odmrzavanje, karakterizacij vazdušnih pora u očvrslom betonu, dinamički modul elastičnosti nakon ciklusa zamrzavanja/odmrzavanja, koeficijent migracije hlorida, statički modul elastičnosti i skupljanje usled sušenja. Ukupan broj uzoraka koji je ispitan iznosi 650, a za njihovu izradu bilo je potrebno napraviti cca 2.5 m³ betona. Analizirani su betoni sa različitim procentom zapreminske zamene sitnog agregata drobljenom gumom (CRC), te sa različitim vodocementnim odnosima (W/C = 0.55, 0.50, 0.45 i 0.40). Na osnovu komparativne analize zaključeno je da zapreminska zamena sitnog agregata drobljenom gumom bitno utiče na svojstva betona u svežem i očvrslom stanju u odnosu na običan (referentni) beton. Pokazano je da se zamenom sitnog agregata drobljenom recikliranom gumom (CRC) u količini do 7.5% mogu dobiti konstrukcijski betoni, odnosno betoni sa zadovoljavajućim fizičkim i mehaničkim karakteristikama

Development of Porous Concrete Pavements with Waste Materials for Flood Control

An inventive design for porous concrete pavement slabs was established in this study. Following the "circularity" agenda and zero waste principles, the design of the permeable concrete mix was founded on several waste/byproduct raw materials, including solidified wastewater treatment sludge (SWS), modified solidified wastewater treatment sludge (MWS), and waste from the desulfurization process (WFDP). Porous concrete was made using cement, waste resources, admixtures, and natural and/or artificial aggregates as component materials. Bulk density, water absorption, compressive and flexural tensile strength, load-bearing capacity, resistance to frost and salt, and abrasion resistance were assessed. Changes in durability and mechanical qualities were tracked as the amount of waste material increased. This study provides a deeper understanding of the properties and possible uses of environmentally modified (green) porous concrete pavement slabs, or pavers, to lower the danger of flooding in urban settings. This concrete is considered environmentally friendly material for sustainable construction because of its porous structure, which significantly assists in regulating stormwater runoff, ensuring infiltration, and reducing the number of pollutants before they reach the groundwater. It has been demonstrated that a specific percentage of recycled materials may be incorporated into porous concrete without compromising the long-term viability or usefulness of permeable concrete, therefore complying with the Zero Waste Agenda and Circular Economy principles

Development of conceptual model for environmental monitoring in underground coal mining

Despite the implementation of various technological solutions, underground coal mining has a significant environmental impact. This paper focuses on the impact of underground coal mines on the environment, with particular emphasis on such mining activities in the Republic of Serbia and stresses the importance of monitoring as a phase of environmental protection. The current practice of environmental monitoring in underground coal mines in the Republic of Serbia lacks systematic and comprehensive procedures, making this research paper an original and significant contribution to the mining industry. The primary objective of this research is to investigate the interaction between underground mining operations and the environment, provide a realistic assessment of the environmental impacts, and emphasize the importance of measuring certain parameters. A conceptual model of environmental monitoring, encompassing global trends and research, as well as the existing institutional framework in the Republic of Serbia, has been developed in this paper. Consistent implementation of this model can help establish quality procedures to reduce the impact of underground coal mining on the environment. The research demonstrates that the parameters with the greatest direct impact on the environment are the mine air (i.e. methane), waste rock disposal, ground subsidence, and indirect impacts such as electricity consumption. These influential parameters are analysed using the example of the Soko brown coal mine

Geochemical Profiles of Deep Sediment Layers from the Kolubara District (Western Serbia): Contamination Status and Associated Risks of Heavy Metals

Global awareness of the harmful effects of heavy metal contamination in soil has increased significantly. Understanding the vertical distribution of oxides and elements is vital for tracing the history of potential contamination. Thus, this study focuses on deep sediment cores primarily composed of quartz and clay minerals from a small village in the western Tamnava Basin of Serbia. The aim was to assess the vertical distribution of 11 oxides and 21 elements and the ecological risks of eight heavy metals by analyzing 250 sediment samples from 18 boreholes at depths ranging from 5 to 58.5 m. Deep sediment core samples were analyzed using energy-dispersive X-ray fluorescence spectrometry (ED-XRF). Potential contamination levels were evaluated within the study area. Additionally, samples were analyzed for total carbonate and organic carbon contents and particles retained on a 0.063 mm sieve. Higher than permitted concentrations of vanadium (V), thallium (Tl), and barium (Ba) were found. Notably, this zone is located above a proposed lithium and boron mine in Gornje Nedeljice, making it crucial for monitoring efforts. Even if mining operations do not commence, examining the deep sediment layers in this rural area remains important. This study offers novel and valuable data on the concentrations of potentially toxic elements in undisturbed deep sediment, serving as a benchmark for future comparisons