https://etalpykla.vilniustech.lt/handle/123456789/101053 2026-04-07T02:17:09Z https://etalpykla.vilniustech.lt/handle/123456789/153827 Lightweight portland cement mixtures with perlite for 3D printing of concrete structures Skripkiūnas, Gintautas; Girskas, Giedrius; Rishko, Liudmyla 3D printed concrete is a special type of concrete that can be laid through a 3D printer layer by layer without any formwork support or vibration. Important performance indicators of this concrete: rheology, mechanical properties, durability, can be optimized by choosing various materials. The purpose of this work is to use a mineral additive - perlite - in 3D concrete. In the studies, the pearlite content was up to 11.5%. Rheological tests of modified cement mortars were carried out using a rotary rheometer Rheotest RN 4.1, determining flow curves, ultimate shear stresses and plastic viscosity after mixing and after 60 min. Volumetric coefficient of water separation was calculated, the density and compressive strength were determined. It can be stated that the pearlite additive improves the formability of concrete mixtures using 3D printing technology, reduces the density of concrete, which increases the stability of the concrete mixture and reduces the thermal conductivity of concrete during the exploatation of the product. 2024-01-01T00:00:00Z https://etalpykla.vilniustech.lt/handle/123456789/153818 Effect of glass processing waste content on concrete properties Pocius, Edvinas; Nagrockienė, Džigita; Pundienė, Ina; Girnienė, Ingrida In this study, a concrete was prepared using glass processing waste, which replaced a certain amount of cement. These experiments were conducted to determine how the amount of glass processing waste affects the properties of fresh and hardened concrete. The experiments used cement, sand, dolomite, chemical admixtures, water and glass processing waste. In the experiments the amount of cement was replaced with glass processing waste from 5% to 30%. For the fresh concrete mixture, density and air content were determined. For the hardened concrete density, compressive strength, flexural strength, and water absorption, were determined. From the tests, it was determined that when up to 20% of the cement was replaced with glass processing waste, the properties of the concrete improved. Based on all the results obtained from the study, it was concluded that the optimal amount of cement that can be replaced with glass processing waste is up to 20%. 2024-01-01T00:00:00Z https://etalpykla.vilniustech.lt/handle/123456789/153808 Renewable and non-renewable primary energy factors for Lithuanian A++ buildings’ heating Grinevičiūtė, Monika; Valančius, Kęstutis Lithuanian A++ buildings are highly energy-efficient, but their heating systems still require energy to operate, and the type of energy used can have a significant impact on the environment. By considering both non-renewable and renewable primary energy sources, policymakers, builders, and building owners can make informed decisions about reducing carbon emissions, improving energy efficiency, and promoting sustainable energy use. This article examines the impact of different heating systems on primary energy (PE) consumption in buildings of different functions (single-dwelling residential building, multi-dwelling residential building, office building) with the same energy class (A++), to determine how much primary energy (renewable and non-renewable) is consumed for building operation and investigate changes in CO2 emissions depending on heat source. Primary energy use is a crucial benchmark for achieving energy efficiency goals in the European Union, but the use and calculation of primary energy factors can be contentious as they can affect the results of various analyses. The study demonstrates that the choice of the heat source is a complex task, as it requires considering the share of renewable primary energy in the final primary energy consumption, particularly in “Nearly zero energy buildings” (Lithuanian A++ buildings) where most of the energy consumed should come from renewable sources. 2023-01-01T00:00:00Z https://etalpykla.vilniustech.lt/handle/123456789/153815 Passive house design aspects and analysis in Lithuania Adomaitis, Rimvydas; Valančius, Kęstutis The article provides an analysis of the environment for the development of energy-efficient single-family dwellings in Lithuania in the context of European Union (EU) requirements, Lithuanian (LT) regulations, and climate change trends. It examines the role of Lithuanian architects and builders and the arsenal of tools and challenges in developing energy-efficient houses. The principles and best practices of the German Passive House Institute for Passive House development, their application in Lithuanian climate conditions, specific Passive Houses built in Lithuania, and their operational results are analyzed. The relevance of monitoring in validating the digital building model’s energy efficiency and comfort results as a critical tool for energy-efficient design and of the built houses from assessed. This paper aims to review the regulatory environment for architects working on energy-efficient homes and identify the main objective factors that make this process difficult in Lithuania. In this article we also aimed to provide an overview of the Passive House certification system as a third-party certification system for energy efficient buildings, its evolution, and the place of Passive House in the context of energy efficient buildings in Lithuania. The study shows that although the situation is improving, several obstacles have a significant impact on holding back the process of developing energy-efficient homes, and their solution requires systematic work and much time, which creates a reasonable risk of not meeting the EU and LT energy efficiency targets for buildings in time. We can also see that Passive Houses, built more than a decade ago, are still topping the list of energy-efficient houses in Lithuania today, thanks to their uncompromising rating system. 2023-01-01T00:00:00Z