Research posters’ eBook: according to 1st WORKSHOP with “Focus on experimental testing of cement based materials”

COST Action TU 140

A review on the effectiveness of FRP and hybrid wrappings for strengthening concrete columns

This review investigates the effectiveness of fibre-reinforced polymer (FRP) and hybrid wrappings in enhancing the axial compressive performance of concrete columns. It focuses on various FRP types, such as CFRP, GFRP, BFRP, and AFRP, as well as their configurations (full, partial, and hybrid). A systematic analysis covers mechanical performance, confinement efficiency, and recent advancements in analytical and finite element models. The review critically compares some selected design-oriented and analysis-oriented stress–strain models, categorizing them based on their applicability to fully and partially confined concrete. Emphasis is placed on low-strength concrete applications and novel hybrid systems. Unlike previous reviews, this study integrates recent experimental data, advanced modelling developments, and hybrid confinement systems into a unified framework, offering a comprehensive and practical resource for selecting and optimizing FRP confinement strategies, particularly for low-strength and partially confined concrete, thus addressing critical gaps in both research and design applications

Experimental and numerical investigation of restrained shrinkage of concrete

To promote the understanding of shrinkage related behaviour of concrete used for tunnel linings the experimental and theoretical investigation including numerical and analytical approach was performed on ring-shaped specimens. Overall one analytical (an.) and two numerical models, namely (i) and (ii) were also developed. Models (an.) and (i) considered the restraining steel ring to be rigid, thus not exhibiting any deformation. Numerical model (ii) considered the steel ring to be deformable. The experimental set-up consisted of a large concrete ring with an inner diameter of 120 cm, an outer diameter of 160cm and 20 cm in height. The restraining steel ring was 5.5 cm thick. Two concrete rings were made, namely R1 with a low compressive strength of ~26MPa and the other, R2, with medium compressive strength of ~40 MPa. The strain was measured in the hoop direction on the inner circumference of the steel ring and on the outer circumference of the concrete ring. Concrete rings were subjected to circumferential drying. Numerical model (ii) predicted critical time to the formation of the first crack to be between 13 and 14 days. The experimentally determined critical time is found to be 11 to 13 days with cracks gradually opening over several days. This was indicated by changes in measured concrete and steel strain. Modelled concrete strain just before cracking was between -20 and -30 % 10-6 m m-1 however, measured concrete strain was ~150 % 10-6 m m-1. Modelled steel strain was between -30 and -40 % 10-6 m m-1 while measured steel strain was between -10 and 20 % 10-6 m m-1. These discrepancies, in particular the positive steel strain obtained in experiments, require further investigation and improvements of the experimental set-up

Innovative Structural Applications of High Performance Concrete Materials in Sustainable Construction

Concrete is the most widely utilized construction material in the world. Thus, any action intended to enhance the sustainability of the construction industry must consider the supply chain, production, distribution demolition and eventual disposal, landfilling or recycling of this composite material. High-performance concrete may be one of the most effective options to make the construction sector more sustainable. Experience proves that the use of recycled concrete aggregates, as well as the partial replacement of ordinary Portland cement with other supplementary cementitious materials or alternative binders, are generally accepted as the most realistic solutions to reduce the environmental impacts, leading to sufficiently high mechanical performances. In structural applications such as those concerning the seismic and energy retrofitting of existing buildings, the use of high-performance cementitious composites often represents the more cost-effective solution, which allows us to minimize the costs of the intervention and the environmental impact. Eventually, the challenge of enhancing sustainability by raising durability of concrete structures is particularly relevant in those applications where maintenance is particularly expensive and impactful, in terms of both direct intervention costs and indirect costs deriving from downtime. The present Special Issue aims at providing readers with the most recent research results on the aforementioned subjects and further foster a collaboration between the scientific community and the industrial sector on a common commitment towards sustainable concrete constructions

Use of steel slag for the synthesis of belite-sulfoaluminate clinker

Belite-sulfoaluminate (BCSA) cements are low-carbon mineral binders, which require low energy consumption and allow the incorporation of various secondary raw materials in the clinker raw meal. In this study two types of unprocessed steel slags, coming from stainless steel production, were incorporated in the BCSA clinkers. The clinker phase composition, clinker reactivity, and the compressive strength of the cement were studied to evaluate the possible use of the slag in BCSA clinkers. The cement clinkers were synthesized by using natural raw materials, white titanogypsum, mill scale, as well as two different steel slags: (i) EAF S slag, which is a by-product of melting the recycled steel scrap in an electric arc furnace, and (ii) la dle slag as a by-product of the processes of secondary metallurgy, in various quantities. Raw mixtures with two different targeted phase compositions varying in belite, calcium sulfoaluminate and ferrite phases were sintered at 1250 °C. Clinker phases were determined by Rietveld quantitative phase analysis, while their distribution, morphology and incorporation of foreign ions in the phases were studied by SEM/EDS analysis. The clinker reactivity was determined by isothermal calorimetry. BCSA cements were prepared by adding titanogypsum. The compressive strength of the cement pastes was determined after 7 days of hydration. The presence of a predicted major clinker phases was confirmed by Rietveld analysis, however periclase was also detected. Microscopy revealed subhedral grains of belite and euhedral grains of calcium sulfoaluminate phases, while ferrite occurred as an interstitial phase. The results showed differences in the microstructure and reactivity of the clinker and cement, which can be attributed to varying amounts of ettringite due to different slag type

CoMS

Zbornik pokriva številne, predvsem tehnične teme, ki so pomembne za trajnostni razvoj gradbenega sektorja, kot ključnega dejavnika pri doseganju ciljev EU za obvladovanje podnebnih sprememb in za prehod v brezogljično družbo. Vsebinsko naslavlja inovacije v gradbenih materialih in tehnologijah, vključno s komponentami za zdravo in udobno bivanje, ter interakcije med materiali in okoljem. Poleg energetske učinkovitosti stavb je v njem zajeto področje širšega razumevanja trajnostnega načrtovanja, gradnje in vzdrževanja stavb ter monitoring, ocenjevanje in modeliranje stavb. Vključuje pa tudi vsebine, ki se nanašajo na krožno gospodarstvo, kot je recikliranje materialov in komponent ter koncepti sanacij stavb, ter na digitalizacijo in avtomatizacijo področja

Extending BIM for air quality monitoring

As we spend more than 90% of our time inside buildings, indoor environmental quality is a major concern for healthy living. Recent studies show that almost 80% of people in European countries and the United States suffer from SBS (Sick Building Syndrome), which affects physical health, productivity and psychological well-being. In this context, environmental quality monitoring provides stakeholders with crucial information about indoor living conditions, thus facilitating building management along its lifecycle, from design, construction and commissioning to usage, maintenance and end-of-life. However, currently available modelling tools for building management remain limited to static models and lack integration capacities to efficiently exploit environmental quality monitoring data. In order to overcome these limitations, we designed and implemented a generic software architecture that relies on accessible Building Information Model (BIM) attributes to add a dynamic layer that integrates environmental quality data coming from deployed sensors. Merging sensor data with BIM allows creation of a digital twin for the monitored building where live information about environmental quality enables evaluation through numerical simulation. Our solution allows accessing and displaying live sensor data, thus providing advanced functionality to the end-user and other systems in the building. In order to preserve genericity and separation of concerns, our solution stores sensor data in a separate database available through an application programming interface (API), which decouples BIM models from sensor data. Our proof-of-concept experiments were conducted with a cultural heritage building located in Bled, Slovenia. We demonstrated that it is possible to display live information regarding environmental quality (temperature, relative humidity, CO2, particle matter, light) using Revit as an example, thus enabling end-users to follow the conditions of their living environment and take appropriate measures to improve its quality.Pages 244-250

First experiences in the development of slovenian sustainable building indicators

The construction sector is recognised as having a key impact on the life on Earth. Consequently, the EU has set clear environmental goals for 2030 and 2050, and is developing policies and tools to achieve them. One of the tools for achieving these goals is to establish a system for the evaluation of the environmental performance of buildings, with the priorities of reducing GHG emissions, saving with natural resources and preserving the environment, while maintaining sustainable development and ensuring a healthy living environment. Slovenia has joined in achieving this goal with a study on the state-of-play, commissioned a few years ago by the Ministry of the Environment and Spatial Planning, as the starting point for the development of sustainable building indicators (SBIs). The research, which included an analysis of the Slovenian legislation, commercial certification systems for sustainable buildings and development in the field of green public procurement, exposed complementary but rather different goals and views. It further showed that the Level(s), which provides a common EU approach in assessing the environmental performance of buildings, seems to be the most appropriate framework and the basis for the development of the Slovenian system of SBIs. The development of the Slovenian SBIs is currently underway within the project LIFE IP CARE4CLIMATE with the preparation of guidelines, data sources and procedures for determining the value of individual indicators for the assessment of buildings. Initial research with key construction stakeholders has shown that the solution must be linked to the national building legislation, computational methods and software tools, and also to the established planning procedures. The analyses have also shown that, parallel to developing such a system, it is essential to provide a functional supporting environment and a specific, purposely designed information platform to connect the stakeholders with the developers of the sustainable building indicators system

Shear performance of reinforced concrete (RC) beams strengthened with mortar-based composites under monotonic and fatigue loading

Reinforced concrete (RC) beams form the backbone of modern structures, yet their performance is increasingly compromised by aging, environmental degradation, outdated design standards, unauthorised modifications, increased load demands, impact damage, poor construction quality, and corrosion. These challenges have significantly heightened the demand for effective structural maintenance and strengthening strategies. While fibre-reinforced polymers (FRPs) are widely adopted due to their high strength-to-weight ratio and design flexibility, their limitations—such as poor fire resistance, environmental toxicity, and incompatibility with concrete substrates—restrict their applicability. In this context, mortar-based composites, including Steel-Reinforced Grout (SRG) and High-Performance Fibre-Reinforced Concrete (HPFRC), have emerged as promising alternatives for enhancing the shear capacity of RC beams. Despite their potential, research on SRG and HPFRC systems remains limited, particularly under cyclic and fatigue loading conditions. This study aims to evaluate the application of SRG and HPFRC jacketing for the shear strengthening of RC beams. The research begins with a comprehensive literature review and the establishment of a database containing 218 samples of RC beams strengthened with mortar-based composites. This database facilitates the analysis of key design parameters influencing shear strengthening performance and assesses the accuracy of traditional empirical models for shear capacity prediction. Subsequently, experimental investigations evaluate the static and fatigue performance of SRG-strengthened beams, with comparative analyses including Carbon Fabric Reinforced Cementitious Matrix (CFRCM) and Steel-Reinforced Polymer (SRP) systems. Unlike these systems, HPFRC, which lacks textile reinforcements, is studied independently to account for its unique mechanical properties. Key parameters, such as shear span-to-depth ratio (a/d), textile density, jacket configuration, and mortar properties, are systematically explored. Results confirm the effectiveness of all strengthening systems in enhancing shear capacity, with fully wrapped SRG systems uniquely capable of transforming failure modes from brittle shear to ductile flexural behaviour. Predictive models for shear capacity and fatigue life were developed for SRG and HPFRC systems based on experimental findings. In addition, nine machine learning (ML) models were developed to predict the shear capacity of FRCM-strengthened beams, with XGBoost achieving the highest accuracy and stability. Shapley Additive Explanations (SHAP) and Partial Dependence Plots (PDP) were employed to enhance model interpretability and identify key factors influencing shear capacity, such as beam depth, concrete compressive strength, and mortar thickness. A novel finite element analysis (FEA) model for SRG systems was also proposed, addressing limitations in existing methods by independently modelling the behaviours of mortar and textile components. This innovation enables accurate simulation of premature delamination in high-density SRG systems, providing a robust framework for future design optimization. This research validates the efficacy of mortar-based composites for shear strengthening of RC beams, advancing understanding and application in both static and fatigue contexts. The findings bridge critical knowledge gaps in the performance of SRG and HPFRC systems, enhance the predictive accuracy of design models, and offer innovative tools and methodologies to improve the resilience of aging infrastructure