Civil Engineering

Research Topic Summary.

Buildings consume about 40% of the EU's final energy, and the European Union aims to reduce this consumption considerably. This creates new requirements for building energy systems: indoor climate and comfort must be ensured by technologies compatible with net-zero building standards. A key driver of these changes is the rapid advancement of Industry 4.0 practices for assessing indoor comfort conditions. This research aims to develop a systematic indoor environment assessment methodology capable of interpreting data from smart sensors and evaluating key comfort parameters. The methods will include analysis of existing assessment practices, climate-chamber experiments, digital modelling, real-building investigations, and the use of digital twins for integrated evaluation.

Research Topic Summary.

The airtightness of a building plays a crucial role in ensuring energy efficiency, reducing operational costs, improving the durability of structures, and maintaining a comfortable and healthy indoor microclimate. However, achieving and maintaining airtightness over long-term operation remains a significant challenge due to variable environmental conditions that affect the performance and durability of sealing materials. These materials serve as connecting elements between different structural surfaces that exhibit dissimilar physical and mechanical properties. Variations in the thermal expansion coefficients of building materials induce stresses at joints and lead to the formation of microcracks. Moreover, the temperature and humidity of the surfaces to which the sealing materials adhere also fluctuate during service life, influencing their bonding performance. Therefore, it is essential to investigate the changes in deformability, tensile and tear resistance, and adhesion strength of tape sealing materials under variable temperature and humidity conditions, as significant alterations in these properties may result in a loss of airtightness in buildings.

Research Topic Summary.

Wood is increasingly used in building construction as a renewable building material with very low CO2 footprint compared to other construction materials such as concrete, metal or masonry. To improve the thermal properties of wooden structures, they are insulated with various thermal insulation materials. The polyurethane foam as a highly efficient thermal insulation material is increasingly used for this purpose. Wood, together with polyurethane foam, is used in construction site and prefabricated structures by pressing, fixing or gluing together. The wood-polyurethane joint in the enclosures is exposed to a variety of temperature and humidity conditions, most of which are variable, and the prediction of the mechanical, thermal and moisture characteristics of both the polyurethane foam and the wood in contact with it requires extensive research. The obtained results will be used to develop efficient and long-lasting solutions for polyurethane foam-insulated wooden partitions for energy-efficient low-carbon buildings.

Research Topic Summary.

Within the EU, the Energy Performance of Buildings Directive Recast (EPBD Recast) emphasises not only energy performance but also smart readiness and adaptive comfort. The SRI is a key instrument meant to rate building smart-capabilities in three functionalities: energy efficiency, occupant needs adaptation and grid signals. Combining these threads, this topic responds to societal needs for healthier built environments, the global trend of smart cities embracing occupant health and comfort, and the scientific impetus to connect smart-building infrastructure, digital twin technologies, IEQ monitoring and occupant data under one decision-support umbrella. This PhD research aims to develop a holistic framework for smart-district operation and monitoring that integrates indoor environmental quality (IEQ) metrics, occupant well-being indicators and the Smart Readiness Indicator (SRI) into a real-time urban digital twin platform.

Research Topic Summary.

With the widespread introduction of renewable energy sources into building engineering systems, the issue of energy production and distribution has arisen. Solar collectors can produce the cheapest and cleanest heat in the summer, while the highest heat demand for building heating occurs in the winter; therefore, it is necessary to find effective solutions for managing seasonal energy imbalances. Considering that in the case of Lithuania, a large amount of energy is consumed for heating buildings during the cold season, scientific research must be devoted to the efficient use of thermal energy and its storage. Accumulating thermal energy during the warm season and using it at least in the transitional autumn period is one of the important tasks. At the same time, it is relevant to use heat from wastewater or other low-temperature sources rather than dissipating it into the atmosphere. In this regard, heat accumulators — both water and ground types — are an important part of building heating systems, and their efficiency depends directly on heat loss, insulation properties, and effective management. A detailed analysis of the literature has revealed a lack of studies on the charging and discharging processes of ground-type thermal accumulators, as well as on their management and control technologies. There is also a lack of research on long-term heat losses in accumulators, assessing both seasonal and annual operating conditions and possible engineering solutions for reducing these losses. The research will focus on the issues mentioned above to increase the energy efficiency of buildings and to contribute to a more even balancing of heat networks at various scales.

Research Topic Summary.

Recently, Lithuania has experienced increasingly frequent heavy rainfalls lasting over an hour. After such downpours, we see flooded streets, pathways, embankments, parking lots, and more. The existing drainage system simply cannot handle the enormous flow of precipitation. In foreign countries, one approach to managing stormwater is a drainage system that consists of a layer of water-permeable pavement, an underlying drainage sub-layer, and a soil base. The use of water-permeable concrete pavements is gradually increasing worldwide due to their advantages: they enable rainwater management, preventing accumulation on impermeable surfaces, and help reduce the noise level caused by tire contact with the road surface. Essentially, the cost of water-permeable pavement is not significantly different from that of high-quality concrete pavers. This pavement is quick and easy to install and can be used to shape curved surfaces. One well-known product on the market is the so-called "stone carpet" – a special polyurethane binder that binds natural or artificial stone to create a durable, water-permeable mixture. Thanks to advanced technology, this material ensures sufficient surface porosity. With well-absorbing soil, rainwater easily infiltrates into the lower layers of the ground. In addressing environmental concerns, a fully natural organic binder – plantain seed husk powder – can be used in these types of surfaces. These surfaces are also air-permeable, making it possible to install them right next to tree trunks. The natural binder, which binds the fine particles of aggregate into granules, maintains the pavement's moist consistency and, in dry conditions, slowly releases moisture. This process creates a consistently elastic surface that is flexible in wet weather and stable in dry weather. This type of pavement is particularly suitable for park pedestrian and bicycle paths