bluuebunny/crossref_metadata_2025_split huggingface dataset:
A review study on specific requirements for refurbishment of military buildings in cold climates
Authors: Prozuemnts A , Borodinecs A , Krizmane M 
Published: December 2019

Abstract
In most cases there are no specific and clear design requirements defined in local building codes, the responsibility for appropriate design of military buildings therefore lies primarily on third party design service contractors that are hired upon a short term agreement, whereas government is primarily involved in financing stages and military personnel is solely involved in long term exploitation of these structures. Authors of this paper focus on analyzing and isolating specific requirements for refurbishment of military buildings with regards to their structural reliability, safety, endurance, fire and explosion-resistance, heating, ventilation and air-condition systems performance and efficiency, as well as adding energy efficiency, building performance optimization recommendations and measures in moderate and cold climate conditions.
Energy performance of temporary shelters
Authors: Borodinecs A , Geikins A , Smirnov S 
Published: December 2019

Abstract
This paper analyzes methods for calculating energy consumption of temporary shelters for the purpose of reducing energy consumption for heating and improving the level of comfort. Mobile shelters are widely used by rescue emergency teams. Often such type of buildings has a limited access to reliable source of energy supply. Thus it is vitally important to make correct heat losses analysis to select proper capacity of energy source. The paper presents analysis of heat losses of rubber/fabric shelters without extra thermal insulation.
Energy saving potential of ventilation systems with exhaust air heat recovery
Authors: Zemitis J , Borodinecs A 
Published: December 2019

Abstract
The paper presents the results of data gathering regarding the heat recovery efficiencies of different heat recovery types at various air flows supplied by some of the most common manufacturers. The study showed that the average heat recovery efficiency of modern, commonly used rotary heat exchangers is around 83% while for counter-flow exchangers around 86%. Also, in the paper, the simulation results of heat energy consumption and recovered heat potential for the single-family house are presented. The simulations are performed in IDA-ICE software and show that for the specific building it is possible to reduce the heating energy up to 84% if ventilation with heat recovery is used. The results also showed that in case the internal heat loads decrease, then it slightly affects the heat recovery potential. In the case of no internal gains, this value decreases by 4%.
Development of the experimental stand for investigation of the drying process in moist walls
Authors: Cieślikiewicz Ł , Łapka P , Mirowski R , Wasik M , Kubiś M , Pietrak K , Furmański P , Seredyński M , Wiśniewski T 
Published: December 2019

Abstract
The paper presents development of the experimental stand for investigation of drying process in a part of a wall which consisted of about twenty bricks joined by mortar. The thermo-injection method was applied for drying. In the first stage of this method several holes are drilled in the moist wall and are used to mount heating probes. These probes supply air to holes and at the same time heat air and the wall up. Then hot air leaves the hole flowing along its boundaries and heating and drying the wall. In the second stage holes are used for impregnation of the wall with hydrophobic fluid which creates waterproof membrane. The stand was based on a precise platform balance applied to measure the variation of global moisture content in the specimen. Moreover, local variations of moisture content were measured applying TDR method. The temperature measurements were carried out using RTDs which were placed in different locations in the wall. Additionally, the IR thermography was applied to register temperature on the specimen surface. The stand was closed in an insulation chamber to decrease the impact of the surroundings. The paper contains the preliminary results of measurements which test operation of the stand.
New numerical model of heat and moisture transfer in the wet brick
Authors: Seredyński M , Furmański P , Łapka P , Wasik M , Cieślikiewicz Ł , Pietrak K , Kubiś M , Wiśniewski T , Jaworski M 
Published: December 2019

Abstract
The subject of this study is numerical modelling of the fully coupled heat and moisture transfer in the building material, i.e., in a brick. The new mathematical model of equilibrium transport of heat and moisture in the form of continuous liquid medium (funicular region), discontinuous liquid medium (pendular region) and gaseous phase with dry air is proposed. As independent variables, the total mass moisture content and temperature are chosen. Both energy and moisture balance equations are mutually coupled. It is due to dependence of capillary and vapor pressures on the moisture content and temperature. Additionally, vaporization and condensation phenomena are also accounted for in the energy balance equation. Both transport equations are supplemented with boundary conditions expressing the coupled heat and moisture transfer at the dried wall or heat transfer at impermeable walls. Balance equations are discretized on the rectangular control volume grid in the framework of the in-house computational code. A grid-based method of generation of the control volume mesh is proposed, with ‘half’ control volumes related to boundary grid nodes created at domain walls. This approach enables deeper insight into implemented code as well as simplifies analysis of influence of selected terms in balance equations and implementation of complex hygro-thermal boundary conditions.
Numerical models for long-term performance assessment of lightweight insulating assemblies
Authors: Birjukovs M , Apine I , Jakovics A 
Published: December 2019

Abstract
This paper presents the results of numerical modelling of hygrothermal processes in test buildings situated in the Botanical garden of the University of Latvia. Long-term performance of wall, floor and ceiling insulating assemblies for five different buildings was simulated using WUFI Pro 6.3. On the experimental side, measurements of temperature and relative humidity at key points of assembles have been accumulated over a period of roughly six years and material samples were taken from building envelope materials for biological analysis. We found that our models rather successfully reproduce the experientially observed temperature and relative humidity dynamics. In the process, we established material models for building envelope components, as well as different parameters that we previously unknown. We also compared mould growth risk predictions via the Sedlbauer critical curve model derived from both simulations and experiment against the results of lab tests conducted on materials samples - all three were found to be in good agreement, indicating that the Sedlbauer model is applicable to local climate conditions, as well as further validating numerical models.
Calculation of initial and long-term heating costs for a nearly zero energy single-family building over 30 years
Authors: Gendelis S , Miķelsons M , Jakovičs A 
Published: December 2019

Abstract
In practice, during the design stage of a building, only the initial costs are taken into account. These costs are also discussed with the customer and optimised with the aim of reducing them. It is the global costs over a longer period that show the real difference in the total expenses of living in a particular house, however. In this study, one newly built, nearly zero energy single-family building was studied in detail using a comparative global cost calculation methodology. The most popular insulation materials, construction types, types of windows, and types of floor construction in Latvia are included in the calculation of the costs. The results demonstrate that initially cheaper building means lower global costs during the analysed 30-year operating period due to initial costs are significantly higher than all other costs including energy costs, meaning that changes in construction type and building materials affect the initial cost more than the long-term energy costs. In parallel, different modern heating systems (including heat pumps) were included in the analysis to calculate and compare heating expenses. The results show that almost all the heating systems have the same energy costs regardless of fuel type for the 30-year period, however, the initial costs of these systems vary due to the different used technologies. Therefore, only the sum of the initial and long-term energy costs provides objective information about heating systems that are optimal in the long-term.
Considerations on transients in a water supply distribution network
Authors: Constantin A , Nițescu C S 
Published: December 2019

Abstract
Lipnița is a village situated in a hilly region, in Constanta County. The water supply system has its own groundwater water source, placed in the middle of the village at a low elevation. Water is conveyed, by a long transmission duct to a storage tank from which it flows by gravity to the consumers. The distribution network has two long mains that intersect in a manifold with isolation valves, situated in the middle of the village. This topology of the system shows high static head for the transmission duct and high elevation differences between the end consumers and those in the centre of the village.
The paper presents an analysis, by numerical simulation, on the transients that occur in two different segments of the system.
The simulation was performed either for the original old steel made network, aiming at identifying the vulnerable cross sections and extreme pressure values. The results showed that maximal pressure values are not dangerous, but cavitation occurs along the pipeline. The same simulation was carried out for the new PEHD pipelines. The change of material and the increase in diameter of the new pipes showed better results regarding pressure variation during transients. Cavitation is avoided.
Velocity modification at the bridge abutments because scour
Authors: Gjunsburgs B , Vilnitis M , Parilkova J , Bizane M 
Published: December 2019

Abstract
At the corner of the abutment were streamline concentration, sharp water level drop and rapid increase of velocity. Formula for calculation local velocity at the abutments is elaborated. Local velocity is depending on open flow parameters, backwater value, rate of contraction by bridge crossings and depth of scour. Relative local flow modification at the bridge abutment at plain river bed, relative local and critical velocities changes during scour at steady and unsteady flow, uniform bed and at bed layering is studied. Comparison of the local velocity with approach flow and mean velocity under the bridge opening was made. The local velocity Vlt
is reducing and the critical velocity V0t is increasing because of the scour within the time step at steady or at unsteady flow. When relative local velocity βV0t/Vlt
becomes equal to one the scour stops. For unsteady flow local and critical velocities are different at any steps of hydrograph because of the increased flow discharge and the scour depth. Dependence of the relative local and critical velocities at steady and unsteady flow, development in time and because of the scour, impact layering of the river bed is presented in paper in Figures and compared with tests results.
Lightweight concrete with expanded aggregate from siliceous rocks
Authors: Zakrevskaya L V , Gandelsman I A , Gavrilenko A A , Lubin P A 
Published: December 2019

Abstract
The purpose of this study is to develop technology for the production of a new building composite made of silicon-containing rocks. An aggregate is foamed granules obtained on the basis of diatomite with the addition of caustic soda, dolomite, water and liquid glass. The material composition, materials processing, physical and mechanical properties have been observed. The problem of alkali-silicate interaction typical for traditional Portland cement and glass phase is solved through the use of magnesia binder. Samples on Portland cement and magnesia binder were obtained, the aggregate content was varied. Some aggregate fractions were used to obtain high packing density in the composite. Concrete was estimated according to density, compressive strength and tensile strength, water absorption and thermal conductivity. Analysis of the material structure was made. The results of the study of the microstructure of synthesized concrete indicate the presence of a cement matrix in which granules of various sizes are tightly packed. The results of X-ray phase analysis of synthesized concrete indicates that the cement matrix consists of forsterite crystals. Approximate savings in the use of concrete with the developed aggregate is about 10-20%. Such savings are possible due to the fact the surface occurrence of siliceous rocks allows them to be mined in an open way with minimal costs compared to other rocks, with a lower calcination temperature during material creation.
Drying Shrinkage Deformation Comparison Between Foam Concrete, Geopolymer Concrete, Disintegrated, and Non-disintegrated Cement Mortar
Authors: Gailitis R , Sprince A , Pakrastins L , Sahmenko G , Kozlovskis T 
Published: December 2019

Abstract
Foamed concrete has been known as a building material for nearly 100 years. In the beginning, it was used as an insulation material with very low density. Since then there have been attempts to make this material more load-bearing and structural. In present-day foamed concrete is being used in soil reinforcement, building blocks and in other sorts of building applications [1]. Another innovative material - the geopolymer concrete has been around only for 40 years. It is being used in buildings and infrastructures objects such as railroads, reservoirs, and houses and others. The main benefit of the geopolymer is that it is green material that is partially made by utilizing waste products. The geopolymer manufacturing carbon footprint is 2 times less than the Portland cement carbon footprint. Another way to reduce Portland cement carbon footprint is to reuse old cement. In the past few decades, there has been a considerable amount of researches regarding the partial replacement of cement using disintegrated cement in cement mortar or concrete. As it is known to obtain powder mineral filler material planetary ball milling is applied, but it is ineffective. It has been discovered that grinding by collision is a more effective method for refining brittle material. One of the ways to refine is to disintegrate with disintegrator. This raises the question of whether old cement disintegration together with sand can improve its long-term properties and what differences do these different cement and alkaline activated compounds have. The aim of this article is to determine the difference of shrinkage deformation for foamed concrete and disintegrated cement mortar which is Portland cement based cement composites and geopolymer concrete which represents alkali-activated cement composites. The size of all shrinkage specimens was 46mm in the diameter and 190mm in height. The shrinkage deformations of the specimen were determined by consistently measuring specimen deformation displacement. Shrinkage deformation values for foamed concrete in the 81st day did reach 11.85mm *10−2, disintegrated old cement mortar 4.88mm *10−2, non-disintegrated new cement mortar 5.02mm *10−2, non-disintegrated old cement mortar 4.33mm *10−2, but for geopolymer concrete, on the 81st day, it was 3.73mm *10−2.
Effect of sodium lignosulfonate superplasticizer on the early hydration of cement with different contents of cubic C3A
Authors: Mezhov A , Kovler K 
Published: December 2019

Abstract
In this research, the influence of the sodium lignosulfonate superplasticizer (LS) on the early hydration of two types of cements containing different amount of cubic C3A was studied. It is shown that at 0.1% addition of LS has no significant influence on the hydration, while at higher dosages LS contributes to the additional formation of ettringite. This phenomenon is observed for both types of cement. The higher ettringite formation was found for the cement containing higher C3A amount. However, LS addition retards the hydration, which is indicated by the reduction of the portlandite amount formed.
Sustainable construction success indicators
Authors: Vilnītis M , Lapsa V A , Veinbergs A 
Published: December 2019

Abstract
The proposed paper examines the success indicators of sustainable construction projects, and its relationship to building codes with specific focus on safety, quality and budget aspects in terms of their implications and impacts prior, during and after construction. Such a research will be very beneficial to the construction industry and the government of all countries in terms of significant money savings and preservation of national wealth and resources through sustainable construction approaches. Consideration of sustainability at the design stage is emphasized. Building safety and the roles of building codes in prevention of structural failures are also covered in the paper together with factors affecting building failures and methods for their prevention in early design phases. Construction process is introduced in the paper from the perspective of modern total quality management. Concepts of quality management, quality control, quality assurance and six sigma and how they relate to building sustainability are discussed with examples. At least the importance of appropriate maintenance of building during expected life time are partly covered in the paper. It was necessary, in an initial stage, to define the key indicators that should be considered in order to assess the main aspects of sustainable construction. This paper intends to present the analysis that was performed in order to select some of quality evaluation indicators.
Life cycle assessment for masonry exterior wall assemblies made of traditional building materials
Authors: Zimele Z , Sinka M , Bajare D , Jakovics A 
Published: December 2019

Abstract
Building materials contribute a significant amount of CO2 to overall greenhouse gas emissions and this environmental impact should be reduced to improve the sustainability of the construction industry. Although new and low-carbon materials are emerging, the majority of materials used are still traditionally produced and are highly carbon intensive, such as masonry blocks and insulation slabs – rock wool or expanded polystyrene. To assess which of the traditionally used building materials are more sustainable, in this paper, wall models of the most widely used masonry blocks and insulation materials were analysed using life cycle assessment. The wall models were created to fulfil the requirements of nearly-zero energy buildings. The assessment showed that the lowest impact on the environment is from aerated concrete blocks and expanded polystyrene insulation, which is mostly due to low weight and raw materials consumption compared to other materials. On the other hand, expanded polystyrene insulation poses more danger to humans and the environment in its use phase than other materials due to emissions during fire and degradation, thus should be used with caution.
Identification and Monitoring of Degraded Real Estate in the Context of Urban Environmental Analysis and Development Planning in the City of Riga
Authors: Amoliņa I , Zīra M , Geipe I 
Published: December 2019

Abstract
Nowadays real estate plays an important role in the life of a person: it is one of the important elements of the quality of life (dwelling, workplace), as well as of public spaces, especially the outdoor space, i.e., the elements that make up the image of the city and the aesthetic enjoyment of the city. The topical issue under consideration is directly related to the physically deteriorated real estate that falls into the category of degraded or even dangerous buildings and structures. The article aims at investigating the problems of identifying, assessing and monitoring the degraded real estate in the context of urban development. The topicality of degraded objects is also observed in the main national and municipal development planning documents. The quality of real estate is assessed by different institutions according to the specificity and necessity of their activity, for example, planning and monitoring of territory development, application of real estate tax, as well as determination of the value of real estate. However, according to the research conducted within the article, information on real estate is not always up to date, available or linked between different holders of information sources. Different institutions evaluate the same thing at different levels of detail, but there is currently no fast, efficient and accurate exchange of information. This can be explained by disorganised administrative and legal issues, as well as the inefficiency of mutual communication.
Asphalt Recycling Technologies: A Review on Limitations and Benefits
Authors: Rathore M , Zaumanis M , Haritonovs V 
Published: December 2019

Abstract
Recycling of asphalt pavements gained popularity in 1970s due to the rapidly increasing cost and reducing supply of oil and hence - bitumen. However, presently there are other reasons to develop this technology, the main being the ability to utilize non-renewable resources. Sustainability of asphalt pavement construction can only be ensured if we are able to utilize the available reclaimed asphalt pavement (RAP) material completely in the new construction. Another potential advantage is the mutual benefit of using RAP in conjunction with warm mix asphalt (WMA). This is due to compensation of hardened binder from RAP with softer binder of WMA. For such mixes, significant energy savings can be realized due to the lower mixing and compaction temperature as well as due to lesser efforts required for compaction. This paper summarises several approaches that can be adopted to maximize the amount of RAP material in asphalt mixtures. In addition, the current recycling practices implemented in the industry are discussed to identify the main reason behind the lacking confidence in using high RAP content in mixes. The environmental and economical benefits of high rate of recycling are also discussed. Finally, the possible research directions that will allow to incorporate high proportion of RAP without compromising the performance of pavement are discussed.
Effect of wetting/drying on the properties of OSB/3 and birch plywood
Authors: Kask R , Lille H , Kiviste M , Tamm R , Lääne J O 
Published: December 2019

AbstractIn this study the thickness swelling (TS), restore dimensions (RD), density (D) and modulus of rupture (MOR), after ten cycles of wetting over/drying, of commercial boards, i.e. 3-layered OSB/3 (“SWISS KRONO“, thickness 12mm) and 9-layered birch (betula sp) plywood with phenol-formaldehyde (UPM-Kymmene, Otepää, Estonia), were investigated according to EN standards. Test samples (dimensions of 290×50×12 mm3) for determination of a change in the investigated parameters, according to the standard EVS EN 326-1:2002, were cut from the boards in the parallel (ǁ - major axis) direction to the face (outer layer) strand. The cutting forehead and the facet edges of the test samples were coated with the water repellent masticKiilto Fibergum(“KIILTO OY“). The specimens were altered by soaking in a tank with water (22±1°C) for 24 hours and dried for 48 hours in a ventilated drying box at 65 ± 1°C. Before testing, the samples were conditioned in a climatic chamber at a relative humidity of 65% at 21°C. The surfaces and cross-sections of the initial dry samples after the first wetting/oven-drying cycles were studied using the X-ray technique. The analytical exponent- and linear-fractional equations were used to approximate the obtained experimental data depending on the number of cycles.