Applied Mechanics and Materials Vol. 887

Abstract: This paper addresses the model validation challenges relevant to representation of inhabitants' presence and behavior in buildings. Motivated by the lack of general guidelines for the evaluation of user-related behavioural models in building performance simulation, the paper underlines the need for rigorous processes toward quality assurance while integrating behavioural representations in building performance simulation applications and processes.

Abstract: This document deals with the determination of thermal transmission properties of wood-aluminium window with vacuum glazing. Test measurements are performed with guarded hot-box method at defined temperature difference. They describe how the support pillars influence temperature distribution on the surface and how the edge vacuum glazing influence the heat flow through window. The deformation of the temperature field due to support pillars is surprisingly small and its range is from 0.20 K to 0.46 K with temperature difference on both sides of approximately 20 K. Decrease of internal surface temperature from the middle of glass to the edge is about 20.04 – 16.15 = 3.89 K.

Abstract: In the last years several projects of medium and high-rise timber-based multi-story buildings have been proposed and developed. In most of the cases timber-concrete composite (TCC) floors play a significant role for the design of the structural slabs due to acoustic performance, fire protection and structural issues. Within several research projects and with the aim to optimize the structural and ecological characteristics of building components the Department of Structural Design and Timber Engineering (ITI) at the Vienna University of Technology (TU Wien) developed timber-steel hybrid beams that can be used independently or combined with concrete floors, proposing for this last case prefabricated and semi-prefabricated timber-steel-concrete ribbed elements that make the most of all this potential.In order to recognize the potential for future market implementation and to demonstrate the competiveness of the developed hybrid ribbed floor slabs, the economic feasibility and the ecological impact, structural elements were analyzed in several case studies. The environmental assessment shows the ecological advantages of the developed concepts and underlines the potential for further developments. This paper contains an introduction on the state-of-the-art floor solutions for timber-based multistory buildings, the fundamental ideas and design concepts behind the timber-steel and timber-steel-concrete proposals as well as a short review of the tests carried until now and results obtained.

Abstract: Within several research projects and with the aim to optimize structural performance, energy efficiency and ecological characteristics of structural building components the Department of Structural Design and Timber Engineering (ITI) at the Vienna University of Technology (TU Wien) developed several wood-based composite systems, which combine timber products with other conventional building materials and components. As a representative example for these developments, this paper illustrates the results of the joint research project “Wood-based concrete: building construction with composite elements of wood-concrete compounds and timber (WooCon)”. The objective of the research project “WooCon” is to develop a multi-layer wall system composed of wood lightweight concrete (WLC), connected timber sections, textile reinforcement as well as glass layers on the exterior to gain and use advantages of each used material - lightweight, structural, thermal storage and insulation, ecological and economic benefits - to name the most important ones. In order to assess the structural physical properties of wood-based composite wall elements, in a first step measurements of the thermal properties with respect to thermal-insulating properties and thermal storage capacity are carried out. In following step, the results obtained are used further to simulate the thermodynamic and hygrothermal building behavior. The aim of the simulations is to investigate the effect of the wood-based composite wall elements to the annual heating demand as well as to the operative room temperature of a typical south-orientated living space.

Abstract: The work deals with the use of waste glass to the polymer anchor material based on epoxy resin, primarily for anchoring to a high strength concrete (HSC). The main aim was to use the largest possible amount of the waste packaging glass by reducing the amount of epoxy resin, which is an expensive material and its production has a negative impact on the environment. Within the experimental verification, the influence of waste packaging glass fraction 0–0.63 mm on the final properties of the polymer anchoring material was observed. To determine the optimal formulation compressive strength, flexural strength, chemical resistance, shrinkage and pull-out test were performed. Based on the evaluation of the results the optimal percentage of filling was determined, when the polymer anchor material showed high strengths, minimal shrinkage, good chemical resistance, optimal consistency for anchoring into the HSC and high anchor bolt pull-out strength.

Abstract: Construction sector has consumed an important percentage of natural resources and generated much of the waste discharged into the environment in the last decades. This is the reason why the social consciousness has strongly grown towards sustainable development. Concepts such as recycle, reuse, reduce and energy saving are gaining importance in obtaining products under a clearly defined objective of a sustainable development. The revaluation of agroforestry waste has established itself as a solution to the problems associated with these wastes and, increasingly, is being incorporated into the manufacture of new materials. The Wood Plastic Composites (WPC’s) are an important group within these new sustainable building materials. WPC’s are obtained from recycled plastics and natural fibres waste. This kind of materials reduces the consumption of resources and the amount of waste. These materials have emerged to replace natural wood in some exterior applications, where the durability of natural wood is most damaged. Natural wood, in addition to the loss of color that suffers in exterior, has other disadvantages such as anisotropy and hygroscopicity. WPC's do not have these drawbacks. In this way, the WPC’s try to imitate the appearance of natural wood, with a good durability outdoors. Because of this, there are numerous companies that develop WPC products with different plastics and natural waste, with the aim of obtaining the best appearance and durability. In this paper, the color degradation of various WPC materials when exposed to ultraviolet (UV) radiation is evaluated. An artificial aging chamber with a fluorescent UV lamp and a colorimeter have been used to quantify the color parameters. Thus, conclusions are drawn on which plastics and residues achieve a minor alteration of color, an aspect highly appreciated in outdoor applications.

Abstract: This presented article deals with two newly designed experimental walls with different measuring sections (5 for each lightweight wooden wall). All fragments meet the standards required for zero and energy-plus buildings, which would be mandatory in Slovakia from the year 2020. The experimental walls are located in central Europe (town Zilina, Slovakia). Description of individual test sections, the measuring technology, data collection, interior technical equipment and outdoor boundary conditions monitoring are introduced. In the future, the experimental research should progressively combine theoretical calculations with real measurement and computer HAM simulation. In this paper, the focus is aimed to the temperature profiles in wall fragments during seven days chosen from the spring period in the year 2017. The results were graphically presented and evaluated from a point of view of continuous temperature measurement in the structure, exterior boundary conditions, wall orientation and surface character (material, color). Also further intensions of research are drawn.

Abstract: Concrete is a quite recent material in the history of architecture. However, there are a large number of buildings whose structure consists on this material nowadays. Despite its excellent performance, concrete has a useful lifetime. When this time comes to its end, the structural element needs to be treated, repaired or replaced. We are getting to the point at which many of the concrete constructions are reaching, or already surpassing, the useful lifetime of the material. At this point, the Carbon Fiber Reinforced Polymer (CFRP) takes on importance, appearing on the market as a modern and high performance tool, in terms of structural reinforcement of the concrete. Nevertheless, this relatively new system presents yet some aspects to study and research, such as its long-term behaviour under extreme conditions. This is the departure point of our research, focused on the response of the CFRP system, both fiber and matrix, to adverse temperature conditions. This high and maintained temperature can be reached in places such as structures undergone to large periods of solar radiation around Equator latitudes, machinery installations enclosures which generate high temperatures focused on specific points, and brief small fires, among other situations, which surpass the maximum service temperature recommended by the manufacturers. In order to study this influence, a comparison of the compressive strengths of three groups of standard concrete test specimens has been carried out. Each group consisted of three cylindrical specimens, all manufactured on the same date. The first two groups were tested after their 28 day curing in chamber: one of them without any confinement and the other with CFRP sheet applied according to the manufacturer's specifications. The third group of specimens spent 90 days on a climatic chamber subjected to a temperature of 75°C, above the maximum temperature recommended by the manufacturer, 50°C. This third group was tested 388 days after their manufacture. In order to obtain a reliable basis on which to compare the effective strength provided by the deteriorated CFRP, it was needed to calculate the acquisition of theoretical strength that the concrete would have reached after the mentioned period of time without any added reinforcement. With all the results, it is possible to conclude that, after this period of heat attack, despite having produced an aesthetic degradation of the CFRP sheets, most of the compressive strength of the specimens remains.

Abstract: The main objective of this case study is to compare whether standardized test methods are able reliably prognosticate the performance of joint sealants and adhesives after installation in a construction. The authors of presented study believe that existing testing procedures intended for testing of bonded and sealed joints do not fully reflect the weather changes exterior surfaces have to withstand. Based on previous experiences a unique geometry of testing sample was used for this purpose allowing the testing of a so-called real joint. A group of test samples was subjected to two normalized test procedures that may influence the resulting behavior of the joint in the exterior. The second group of test samples was exposed to the external environment for a particular period. The obtained results of tests show that the standardized methods are able to simulate an outdoor environment, however, only to a certain level. Unfortunately, these methods do not consider the possibility that the sealed or bonded joint might be damaged already during the application itself. While laboratory environment is clean and often dust free, it is not possible to ensure the same conditions in situ. Moreover, in some cases it was monitored that some of the selected sealants tested in an external environment aged rapidly compared to the ones cured and stored in the laboratory. In some cases, the difference between monitored failure modes for indoor and outdoor environment was substantial. The predominant type of sealant failure observed in-situ was adhesive while mainly cohesive failure was monitored in laboratory.