Repository of the Institute for Material Testing (RIMS)
Not a member yet
1132 research outputs found
Sort by
Izazovi ispitivanja materijala u arheologiji. Rimski malteri Dunavskog limesa u Srbiji
No full textMalter je jedan od najsloženijih istorijskih materijala i posledično jedan od najizazovnijih za istraživanje, s obzirom na njegovu kompozitnu prirodu, odnosno brojnost mogućih komponenata i njihove međusobne reakcije tokom pripreme, vezivanja, očvršćavanja i starenja maltera. Zaključci istraživanja projekta MoDeCo2000 vezani su za identifikaciju materijala upotrebljavanih u istorijskim malterima i tehnologija pripreme maltera, kao i mogućnosti pripreme i primene maltera za konzervaciju - kompatibilnih istorijskim, ali i dovoljno otpornim na uticaje kojima su danas izloženi ostaci građevina. Uzorci istorijskih maltera prošli su kroz vizuelni pregled i utvrđivanje fizičko-mehaničkih karakteristika, mineraloško-petrografskog i hemijskog sastava, upotrebom više laboratorijskih tehnika (TL-OM, SEM-EDS, XRPD, Ramanska spetroskopija, FTIR, XRF, ICP-OES, DTATG, DSC-TG-MS). U istraživanjima projekta MoDeCo2000 učestvovalo je više istraživača iz Srbije i inostranstva. Upravo je mogućnost uporednog ispitivanja različitih fragmenata istih uzoraka u više institucija donela velike izazove. Razlike i sličnosti između dobijenih rezultata naglasile su neophodnost njihovog pažljivog tumačenja u cilju donošenja najrelevantnijih naučnih zaključaka, ujedno nas podsećajući na važnost dobro poznatog pojma reprezentativnosti uzorka i adekvatnog odabira tehnika ispitivanja, odnosno poznavanja njihovih prednosti, ali i ograničenja
Impact of socket outlets on the fire resistance of gypsum partition walls
No full textThis study presents the results of fire resistance testing performed on 12 configurations of
gypsum partition walls composed of 12.5 mm thick gypsum boards mounted on CW/UWmetal
studs with profiles of 50 mm and 100 mm. The wall assemblies were constructed with either
single- or double-layer cladding on both sides, and the configurations varied based on the
presence and placement of socket outlets: walls without outlets, walls with outlets on the
fireexposed side, and walls with outlets on the unexposed side.
Fire resistance testing was conducted in accordance with the SRPS EN 1363-1 standard using a
full-scale fire testing furnace.Wall specimensmeasuring 1.0 m× 1.0mwere tested across three
groups:
• Test Group 1: Reference walls without socket outlets, tested in all four quadrants of the
furnace. These included combinations of 50 mm and 100 mm metal studs, with either
single- or double-layer gypsum board cladding.
• Test Group 2: Walls with single-layer cladding and embedded socket outlets installed
on either the fire-exposed or unexposed side, with both stud sizes represented.
• Test Group 3:Walls with outlets embedded in the center zone, comprising both singleand
double-layer configurations and both stud sizes. Outlet orientation again varied
relative to fire exposure.
The primary objective of the study was to assess the impact of real-world modifications –
specifically, the integration of socket outlets—on the fire resistance of gypsum wall systems,
compared to idealized configurations typically evaluated in standardized testing. The goal was
to provide insights into how these common installations influence thermal and structural
performance during fire exposure.
During testing, temperatures were continuously recorded on the unexposed wall surface and
behind the socket outlets. In accordance with the standard, the maximum permissible
temperature rise was limited to 180°C above ambient. In addition to thermal insulation
performance, structural integrity was visually monitored. A wall specimen was deemed to have
failed once either the temperature threshold was exceeded or visual integrity was compromised.
Among the tested configurations, the wall assembly featuring double-sided, double-layered
gypsum boards with CW/UW 100 profiles and no socket outlets exhibited the highest fire resistance, maintaining both integrity and thermal insulation for 92 minutes. In contrast, the
weakest-performing samples were:
• A wall with double-sided, single-layer cladding on CW/UW 50 profiles, with an outlet
installed on the fire-exposed side; and
• A similar configuration with CW/UW 100 profiles. Both failed after 25 minutes due to
loss of integrity and insulation.
Overall, the results confirmed that the presence of socket outlets significantly affects fire
performance. Wall assemblies without outlets consistently demonstrated superior resistance.
Assemblies with outlets installed on the fireexposed side performed worse than those without
outlets but better than configurations with outlets on the non-exposed side. This somewhat
unexpected outcome is attributed to the melting of the outlet on the fire-exposed side during
early fire stages, leading to partial internal board failure. This localized collapse removed the
weakened inner layer, allowing the metal stud frame and remaining cladding to continue
performing as a fire barrier. Conversely, outlets on the unexposed side remained intact in early
stages, allowing heat to penetrate more deeply into the wall cavity, ultimately accelerating
structural and thermal failure.
These findings emphasize the critical role that outlet positioning plays in the fire performance of
partition walls. In addition to the number of gypsum board layers, the orientation and placement
of embedded socket outlets must be carefully considered when designing fire-rated assemblies,
particularly in residential and commercial buildings with heightened fire safety requirements
From lab to industry: Analysing the performance of ceramic batch modified with sodium silicate and phosphoric acid-based additive in ceramic floor tile production
No full textThis study investigates the use of CERADIT+ , a mixed phosphate-sodium silicate additive, to enhance porcelain
stoneware ceramic tile properties during a 50-minute cold-cold firing cycle. Used in amounts up to 0.50 %,
CERADIT+ acted as a firing binder, with optimal mechanical properties observed at 0.25 % in lab tests. Scale-up
trials maintained consistent raw materials and processing steps, including wet milling, spray drying, pressing,
and firing, with compaction pressures between 300–330 kg/cm² and thicknesses of 7.0–8.1 mm. Instrumental
analysis tracked mineralogical changes and gas evolution during firing. All the laboratory and industrial probes
with CERADIT+ met standard floor tile specifications. However, the modulus of rupture and water absorption
varied among the industrially-fired tiles, indicating a possible agglomeration of the additive-derived phases
during firing. Notably, a low quantity of berlinite agglomerated in the additive-enhanced tiles. This mineralogical
shift suggests a distinct reaction pathway introduced by the additive. Furthermore, introducing sodium
silicate in a low amount promoted better densification of the fired pieces. The findings support CERADIT+ as a
viable additive for industrial ceramic tile production, and future research will explore its optimization across
different ceramic bodies. Using this additive is expected to achieve up to 30 % savings in natural gas consumption
and a corresponding reduction of up to 30 % in CO₂ emissions
Recovering hydrated cement from recycled concrete for improving technological properties of engineering bricks
No full textIn Europe, around 500 million tons of construction and demolition waste (C&DW) are generated annually, a third
of which is concrete. Recycling mainly focuses on coarse aggregates, but 20–30 % v/v of the output includes fine
particles and hydrated cement powder (HCP). As HCP can be partially reactivated at 450–650 ◦C, its reuse in
clinker production is under study, though high energy demands hinder its viability. This research investigates an
alternative: substituting clay with up to 30 % HCP in fired clay bricks, leveraging the high-temperature process
already involved. Bricks were fired at three temperatures and characterised in terms of mechanical, mineralogical,
chemical, and thermal behaviour. A life cycle impact assessment evaluated environmental feasibility.
Results show that HCP enhances brick properties, especially at higher firing temperatures. However, despite
improvements such as reduced thermal conductivity, global warming potential and water consumption impacts
are higher, posing a trade-off between material performance and environmental cost
Advancements in Soft Sensor Technologies for Quality Control in Process Manufacturing: A Review
No full textRecently, Machine Learning has become a crucial tool for enhancing process quality control in manufacturing plants. However, real-time assessments are often challenging. Soft sensors, which can predict process quality indicators using machine learning, have gained significant attention since 2000 because of their advantages, such as process stability, reduced product rejection, and improved energy and fuel efficiency. Oil distillation, polymers, cement, and steel were the primary industries that developed soft sensors for quality indicators. Over time, more industries have adopted these models owing to the advantages previously mentioned. Machine learning algorithms for processing soft sensors have evolved from simple linear algorithms to complex deep learning models with neural networks, support vector machines, and tree-based models also being widely used. This paper summarizes the methodologies implemented in soft-sensor technology during this century. To this end, a comprehensive selection of articles from different processes using machine learning algorithms was analyzed and discussed. As data availability and computing power increase, deep learning algorithms will become the primary focus of soft sensor research, which will help lower energy consumption, enhance production rates, and reduce CO2 footprints
Developing of heat flux meter for fire resistance test
No full textFire resistance tests are important in the phase of a fully developed fire that starts in buildings and refers
to structural, separate elements. Fire resistance of constructions could be determined in two ways: by
calculation method or in standard test furnaces. In the standard furnace, according to the European standard
EN 1363-1, there are following parameters like: temperature inside the furnace, temperature on the specimen
measured on the non exposed side, and pressure in the furnace. In addition to these parameters, it would be
important to have information about the value of heat flux through specimens. Heat flux through specimens
represents the crucial parameter in the energy balance of the test furnace, and of course, the energy balance of
the specimen. During the examination, the most important information, for the test specimen, is the
temperature measured on the non exposed side, while heat flux through the specimens is still unknown. Heat
flux value could be used as input for future numerical models exposed to fire. In this paper the developing of
heat flux meter for the determination of heat transmittance through these constructions has been presented.
The heat flux inside the furnace caused by radiation and convection has stochastic unpredictable nature. All of
these processes are very fast and measuring of exact heat flux value is only possible with thin heat flux meters.
The thick heat flux meters can measure the same but with increased delay time which is caused by heat flux
meter inertia. This is the advantage of this type of heat flux meter because it creates smoother heat flux curve
with lower noise than thin flux meter. The developed thick heat flux meter is a 1D conductive heat flux meter
that works on the thermopile principle. Based on thermopile voltage value is possible for heat flux to be
determined. The thermocouple K is also placed in the heat flux meter. The thermocouple type K has the
temperature range -270°C to 1260 °C, which records the exact temperature of the developed device. The
validation and verification of this type of heat flux meter is divided into four phases. The first phase represents
the fire resistance test of a wall made of hollow brick where the innovative heat flux meter was placed inside
the hollow brick. In the second phase, the mathematical model based on the temperature difference of the
conductive heat flux meter has been developed. In the third and fourth phase, the radiative heat source
according to the standard EN 9239-1 has been used for verification of the performance of the developed heat
flux meter. This device could be used for all types of furnaces. In the future the 2D and 3D heat flux meters
would be developed. These flux meters could be used for determination of heat fluxes through all axes
AI-driven models for prediction of ceramic tiles’ properties and detection of the influences: Behavior during shaping and drying
No full textThe 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
Primena površinski aktivne supstance ARKOPALA N 100 u ciglarstvu
No full textU radu je ispitivana mogućnost primene ARKOPALA N 100 u ciglarskoj industriji.
Pomenuta supstanca je dodata u vodu sa kojom se vlažila prethodno osušena i prerađena sirovina.
Formirana su četri kompozita. Koncetracija ARKOPALA N 100 je varirala od 0 do 0,07%. Proces
sušenja praćen je na uzorcima pločica. Snimljen je set izotermskih eksprimenata za svaki kompozit.
Konstrujisane su zavisnosti efektivnog koeficijenta difuzije u funkciji od sadržaja vlage (Deff-MR).
Oblikovani uzorci kockica su sušeni na 250C pri relativnoj vlažnosti od 75% dok apsolutni sadžaj
vlage u njima nije spušten do 15, 10 i 5 %. Formirane su zavisnosti promene prtisne čvrstoće
oblikovanih uzoraka u funkciji sadržaja vlage. Dobijene krive omogućile su nam da objektivno
pratimo generisanje pukotina tokom sušenja i utvrdimo optimalu koncetraciju ARKOPALA N 100
koja omogućava da se iste izbegn
Utilisation of recycled concrete powder as Supplementary Cementitious Material: Pathway to the Serbian technical assessment
No full textUsing a Supplementary Cementitious Materials (SCMs) as a strategy for reducing CO2
emissions, is widespread. A growing demand for SCMs has led to exploring new materials capable
of reducing the environmental impact, such as recycled concrete powder (RCP), without significantly
impairing the essential characteristics of cement. This paper presents the results of possibility of use
the of RCP as SCM as well as the procedure for creating the Serbian technical assessment for this
construction product. The possibility of utilization of RCP as SCM was assessed through the chemical
composition, physical and mechanical characteristics. The results of the research showed that RCP
can be used as SCM. Based on the results of the research, the preparation of the Serbian assessment
document of this innovative product was initiated. This provided the possibility of making available
this product on the Serbian market