Repository of the Institute for Material Testing (RIMS)
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Green roofs – Legislation in the Republic of Serbia and Europe
No full textThe adoption of green roofs in the Republic of Serbia remains limited due to multiple
barriers, including the absence of supportive legislation, lack of financial incentives, low public
awareness, high initial costs, and ongoing maintenance requirements. In contrast, green roofs are
increasingly integrated into urban planning globally, particularly in major cities where building
regulations often mandate their inclusion. In Europe, green roofs have become a standard, with
Germany leading the way through pioneering laws that encourage their installation on both new and
existing structures. This paper examines international legislative frameworks to assess the potential
for developing technical regulations to advance green roof implementation in Serbia
Comprehensive characterization of natural bentonite clay: Implications for enhanced performance in ceramics manufacturing
No full textPotential industrial applications of bentonite from a regional deposit were investigated. The material was investigated beyond state-of-the-art to optimize its quality for use in ceramic sector. Representative bentonite samples (B1, B2, B3) were analyzed. The grain size was determined by wet sieving and laser diffraction analysis. Clay fractions were analyzed using XRD. Chemical composition was assessed by AAS technique. Structural features, inclusions, and microcracks were monitored by scanning electron microscopy. Physicochemical parameters included swelling index, total cation exchange capacity, exchangeable cations type, refractoriness, water adsorption capacity, and plasticity index. The types of chemical bonds were determined by FTIR. DSC/TGA was employed in the thermal behavior analysis. The investigation revealed that samples are non-swelling Ca-type bentonites. XRD analysis indicated presence of major mineral montmorillonite, accompanied by cristobalite, feldspar, and calcite. The examined bentonites display high plasticity, adequate swelling/water absorption, viscosity, and thixotropy, making them well-suited for ceramic industry applications
Some aspects of the comparative analysis of Environmental Product Declarations (EPDs) for clay construction products
No full textWhen creating an Environmental Product Declarations (EPDs), it is necessary to establish Product Category Rules (PCR). PCR is a group of rules, requirements and guidelines on the basis of which the Environmental Product Declaration (EPD) is formed. The Product Category Rules (PCR) are used to complement the General Program Instructions (GPI), e.g. in terms of calculation rules, production scenarios and content of the EPD declaration. They ensure that functionally similar products are evaluated in the same way when performing Life Cycle Assessment (LCA) and for product comparison. They represent a key part of the ISO 14025 standard as they enable transparency and comparability between EPD declarations. This study examines key findings from Environmental Product Declarations (EPDs) for clay construction products conducted using two platforms: the EPD Hub and the International EPD System. It analyzes parameters such as Global Warming Potential (GWP) from fossil sources, total GWP, freshwater consumption and energy consumption, with results standardized to a functional unit of 1 kg for the product stage, modules A1-A3. Based on the results of the analysis, as well as the rules of the ISO 14025 standard, comparability of EPDs for construction products is possible only within the same product group and within the same program operator. Also, the comparability of EPDs for clay construction products is conditioned by the choice of specialized software in which the LCA of the product is modeled, as well as the selection of specific or generated data from available databases for each stage of the product's life cycle.predavanje po poziv
Optimization of Ceramic Tile Properties Using CERADIT+ Additive: A Phosphate- and Sodium Silicate-Based Binder for Fast Firing
No full textThis study investigates the effects of CERADIT+, a mixed phosphate- and sodium silicate-based additive, on ceramic tile production during a 50-minute cold-cold firing cycle. The additive, used in quantities up to 0.50%, demonstrated its role as a firing binder, with optimal mechanical properties observed at a 0.15% share under laboratory conditions. Scale-up trials were conducted using industrial batches with and without the additive, followed by wet milling, spray drying, pressing, and firing, with each processing stage analyzed. Compaction pressure varied between 300–330 kg/cm² for 330×330 mm tiles, with thickness ranging from 7.0 to 8.1 mm. Instrumental analysis tracked mineralogical transformations and gas evolution during firing. Standard compositions contained quartz, mullite, and gehlenite, while tiles with the additive formed berlinite. Results confirm CERADIT+’s suitability for floor tile production, meeting industrial specifications. Future research will refine additive quantities for broader ceramic applications.poste
The influence of crumb rubber on the chloride penetration resistance of concrete
No full textThe growing environmental concern associated with the disposal of waste automobile tires has
intensified research into their potential reuse in the construction industry, particularly in concrete
production. This study focuses on evaluating the effects of incorporating crumb rubber as a partial
volumetric replacement of natural fine aggregate in concrete, in amounts of 2.5% and 7.5%. Special
emphasis is placed on the impact of these substitutions on the resistance of concrete to chloride ion
penetration, which represents one of the primary causes of reinforcement corrosion in structures exposed
to aggressive environments such as bridges, marine structures, and de-icing salt-treated roads. The
experimental program includes two series of concrete mixtures with different water-cement ratios (0.45
and 0.55), enabling a comprehensive evaluation of the role of crumb rubber in concretes with varying
density and porosity. For each mixture, compressive strength was determined at 3, 7, and 28 days, while
resistance to chloride ingress was assessed through the determination of the chloride migration
coefficient in accordance with the EN 12390-18. The results indicate a decrease in compressive strength,
particularly at early ages, with a more pronounced effect observed in mixtures containing higher
amounts of rubber. However, mixtures with 7.5% crumb rubber and a lower W/C ratio exhibited
improved chloride resistance compared to the reference mix. The findings suggest that the use of crumb
rubber can enhance the durability of concrete, especially in terms of its resistance to chloride penetration,
provided that the rubber content is carefully optimized. This approach not only contributes to solving
the problem of waste management but also opens the door to the development of more sustainable and
durable concrete structures
Metode rapidne ocene seizmičke otpornosti zidanih zgrada bez krutih tavanica: studija slučaja školske zgrade
No full textUnreinforced masonry structures without rigid floor diaphragms are particularly susceptible to earthquake-induced damage. Walls which are perpendicular to the lateral action can collapse out of their plane, posing an immediate danger, while also compromising the integrity of other structural and non-structural components. In the Republic of Serbia, a sizable portion of public facilities, as well as single-family homes, is housed in relatively old buildings of this type. In this paper, two displacement-based procedures are employed to assess the seismic performance of a school building which has previously undergone an inspection and a condition assessment. The first method is based on rocking block mechanics, while the other one relies on the principal mode shape. The investigation is carried out to evaluate and compare the methods and their applicability to routine assessment of masonry structures. Analytical procedure, based on rocking block mechanics, was found to be easy to automate and less sensitive to unreliable input parameters than the second procedure, which relies on numerical analysis
Očuvanje životne sredine kod podzemne eksploatacije uglja u Srbiji
No full textOvaj rad se fokusira na značajnu ulogu uglja u proizvodnji energije, kao i na izazove koji se javljaju pri njegovoj
eksploataciji, posebno kada je reč o zaštiti životne sredine. Proizvodnja uglja, bilo putem površinske ili podzemne
eksploatacije predstavlja glavnu delatnost u mnogim zemljama, uključujući i Srbiju, jer je ugalj i dalje glavni energent
za proizvodnju električne energije. Važno je naglasiti da se u rudnicima uglja koristi širok spektar tehnoloških rešenja
koji imaju direktne posledice na životnu sredinu, a pred stručnjacima koji se bave eksploatacijom uglja stoji najvažniji
zadatak: maksimalno ekonomično i sigurno eksploatisati ležišta uz minimalno ugrožavanje životne sredine. Očuvanje
životne sredine postaje ključno kako bi se utvrdilo da li su aktivnosti eksploatacije ugrozile životnu sredinu, u kojoj
meri i kako bi se blagovremeno i efikasno sprečile odnosno uklonile neželjene posledice zagađenja. Korišćenjem
odgovarajućih zaštitnih mera, primenom novih tehnologija kao i kroz edukaciju i obuku tehničkog osoblja rudnika,
moguće je kontinuirano poboljšavati prakse zaštite životne sredine, a čime se smanjuje rizik od zagađenja i negativnih
efekata na okolinu. To je neophodno kako bi se održavala ravnoteža između potreba za energijom i očuvanjem životne
sredine
New insights in the composition of provincial Roman mortars - Lederata fort in Serbia
No full textThe frontier of the Roman Empire consisted of a series of military fortifications, along which civilian settlements and infrastructure were built with life flourishing in all its aspects, transforming the landscape into a place of exchange, interaction and connection between people. It stretched over 7,500 km, and in today's Serbia, the border followed the Danube River for its length of 588 km. During the MoDeCo2000 project, mortars from 24 Danube sites in Serbia were sampled (mostly bedding and core mortars), dated to the period from the 1st to the 6th century, to design compatible conservation mortars. Additionally, raw materials (lime, schist, clay, and natural brick) were collected from sites assumed to have been exploited by the Romans. In this presentation, a very brief overview of the results of the research on a particular core mortar is given, which stood out due to its exceptional mechanical features and durability and brought new understanding of mortars from the Roman period in the territory of today's Serbia. The mortar belongs to a rampart of the first Lederata military fort phase built during the Trajanic period, at the beginning of the 2nd century
Investigation of the Mechanical Properties of Concrete Incorporating Recycled Rubber Particles
Get PDFQuantity of waste rubber generated by automobile tires is growing, posing an environmental threat. Rubber tire recycling was studied for usage in asphalt and waterproofing systems during past few decades. Globally, concrete is the most widely used building material. About 7% of CO2 emissions come from the cement production. The purpose of this research is to assess if using waste rubber and Portland cement together in composite material for structural applications is feasible. Waste tires (shredded to 0/1 mm) were used as fine aggregate replacement (in 2.5 and 7.5 %), together with PC and natural stone. An investigation of properties in fresh (slump test, bulk density, air content) and hardened state (bulk density, compressive strength) was performed on the rubberized concrete. The compressive strength decreased by increasing the rubber content for all w/c ratios (0.55-0.4). The addition of fine-sized rubber did not cause a retardation in cement hydration mechanism. According to the obtained compressive strengths, all designed rubberized concretes belong to a group of structural concretes
Advanced machine learning models for the prediction of ceramic tiles’ properties during the firing stage
No full textThe firing stage is a critical phase in ceramic tile production, where the interplay of raw material composition and thermal treatment determine essential properties such as water absorption (WA) and bending strength (BS). This study employs advanced machine learning (ML) models to accurately predict these properties by capturing their complex nonlinear relationships. A robust dataset of 312 ceramic samples was analyzed, including variables such as particle size distribution, chemical and mineralogical composition, and firing temperatures ranging from 1000 to 1300 °C. Among the four ensemble ML models evaluated, CatBoost demonstrated the highest predictive performance. Model accuracy was assessed using multiple evaluation metrics, including the coefficient of determination (R²), root mean squared error (RMSE), mean absolute error (MAE), and mean absolute percentage error (MAPE). To enhance interpretability, SHapley Additive exPlanations (SHAP) were used, revealing that clay mineral content and SiO₂ concentration were the most influential factors for WA, contributing approximately 40% and 30%, respectively. For BS, firing temperature (35%) and Al₂O₃ content (25%) were identified as the key predictors. Partial dependence plots further illustrated critical thresholds, such as a significant drop in WA above 62% SiO₂ and optimal BS values near 1200 °C, dindings that align with known ceramic processing principles while offering new, data-driven formulation insights. These results demonstrate the value of explainable artificial intelligence (AI) in enabling real-time process optimization, enhancing product consistency, and supporting energy-efficient ceramic manufacturing. Future work will focus on extendingthe dataset to include a wider variety of clay compositions and investigating hybrid modeling approaches for further improve predictive performance