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Translation abstract Analysis of Flow Rates in Cracked Reinforced ConcreteCracks in reinforced concrete structures are part of the construction principle and acceptable as long as they do not exceed certain limits. According to Eurocode 2, part 3, (as well as the guideline of the German Committee for Structural Concrete (DAfStb)) the autogenous healing of separation cracks with a width ≤ 0.20 mm can be considered under certain hydraulic conditions. However, practical experience shows that self‐healing does not always reliably occur even when this crack width is maintained. This study examines the flow rates of centrally cracked and water‐permeated concrete using Edvardsen's method. Based on the experimental results, an analytical approach following Hagen‐Poiseuille is developed to estimate the flow rate immediately after the start of the water flow, which is particularly relevant for tightness class TC0. This flow rate also serves as an indicator for evaluating the efficiency of autogenous self‐healing in structures of tightness class TC1. The initial flow rate Q0 through cracked concrete is mainly influenced by the crack width distribution across the cross‐section, the water pressure, the roughness of the crack flanks, and the tortuosity of the crack path. Therefore, a reliable estimation of the flow rate necessitates the introduction of a correction factor ξ, which is proposed with 0.52 due to the high variability of the experimental data. [ABSTRACT FROM AUTHOR]

Influence of increasing fresh concrete and concrete hardening temperatures on concrete properties The influence of climate change is manifested in a steady increase of days with hot weather conditions, which significantly increases the probability of elevated fresh concrete temperatures (>30 °C) during the production, placement and hardening of the concrete. Such climatic conditions represent a challenge for concrete construction, due to the fact that without energy‐ and CO2‐intensive countermeasures, such as cooling the raw materials, an increase in the temperature of the concrete during processing and hardening is highly to be expected. This leads to an influence on hydration, which usually manifests itself in an accelerated decrease in workability and a reduction in mechanical properties and durability. The aim of this article is to gain a better understanding of the influence of increased fresh concrete temperatures on the above‐mentioned properties. Furthermore, the influence of the so‐called hardening temperature – the ambient temperature up to the concrete age of three days – on the concrete properties was investigated. For this purpose, temperatures up to 40 °C were investigated. [ABSTRACT FROM AUTHOR]

Durable and sustainable corrosion protection of reinforcing steel in waterway structures Corrosion damage due to hitherto widely unknown damage mechanisms, the critical review of previous design principles, but also new developments in building materials are leading to a reorientation in the design of measures to ensure the durability of hydraulic engineering structures with regard to reinforcing steel corrosion. [ABSTRACT FROM AUTHOR]

Conserved through modernisation, membrane roofs refreshed Many membrane projects were realised in Europe in the 1990s. After more than 30 years of use in some cases, many of these structures are now due for roof renewal. The aim is to continue using them on a long‐term basis, restore their original attractive appearance and preserve their stability for many years to follow. The examples presented show different reasons for renovation, but also different approaches to their modernisation. [ABSTRACT FROM AUTHOR]

UHPFRC in bridge strengthening – examples and challenges UHPFRC stands for ultra‐high‐performance fibre‐reinforced cementitious composite material, which, because of its material properties, is well suited for the rehabilitation and strengthening of reinforced concrete bridges. A layer of UHPFRC increases the resistance of reinforced concrete elements and functions also as waterproofing layer. While the material is already widely used in Switzerland, especially for bridges, it is relatively unknown in the rest of the world and is hardly applied. There are several reasons, the lack of standards is only one of the challenges to address. To improve the conditions for implementing UHPFRC in Germany and other countries, it is necessary to work together internationally. The experience from Switzerland, with more than 350 realized UHPFRC projects, could be used by other countries to launch a new European standard. [ABSTRACT FROM AUTHOR]

Durability of High Performance Aerogel Concrete Various publications have reported on the development of a novel concrete based on silica aerogels, the so‐called High Performance Aerogel Concrete (HPAC). In addition to its excellent fire and noise protection properties, HPAC has a very low thermal conductivity with relatively high compressive strength and is therefore suitable for the production of monolithic exterior components without additional thermal insulation. In order to expand the possible uses and applications of the new material, it has been continuously optimized and further developed at the Institute for Structural Concrete at the University of Duisburg‐Essen since its presentation in 2016. This concerns, for example, the optimization of the material with regard to the material structure and the use of alternative binders or the description of the load‐bearing behavior under compressive and tensile stress. In the future, HPAC will be used primarily in building construction for monolithic exterior walls of buildings that meet the requirements of the German Energy Saving Ordinance (EnEV)/Building Energy Act (GEG). In order to be able to open up further areas and fields of application in the future, it is essential to take a look at the durability properties, which are presented in this article. [ABSTRACT FROM AUTHOR]

Copyright of Kieferorthopädie: die Zeitschrift für die Praxis is the property of Quintessenz Verlags GmbH and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The technical rules for maintenance and the question of scale in the event of "damage/defects" in legacy cases Wiens/Raupach and Helm have studied the technical rules for maintenance of the German Institute for Building Technology (Deutsches Institut für Bautechnik) of 2020 with new contents and constructional framework conditions, including their application [1]. Schießl‐Pecka/Strehlein have described the repair method as specified in the technical rules for maintenance and the relevance of the W (water reduction) repair principle in particular, in combination with hydrophobic treatments, from the planner's perspective [2]. The basis for the scenarios depicted is essentially the application where repairs need to be carried out on an ageing reinforced concrete structure. In addition to this basic case, the situation also arises where there are indications that a reinforced concrete structure that has already been repaired is in need of further repairs, and consequently action is required. A special case is to be added to these legacy cases – which carry the designation "damage" in legacy cases (repair damage) – which is characterised by defects in repairs carried out on a reinforced concrete structure which come to light in an open‐ended warranty period and the customer asserts claims due to material defects (rectification of repair defects in an open‐ended warranty period, repair defects). Legal rules therefore apply in addition to the applicable technical rules. The article concerns itself with the technical and legal questions that arise in this regard, that also touch on the area of application of the technical rules for maintenance and in particular emphasise the significance of the performance description in contract specifications. [ABSTRACT FROM AUTHOR]

Concrete basins according to ZTV‐ING Concrete retention basins within the German federal highways network are regulated in ZTV‐ING. Taking into account the current state of the art and the experiences of the road administration with regard to the construction and operation of such basins and pump houses, a new assignment of the exposure classes for these components should be appropriate. This article takes a differentiated view on the relevant environmental impacts of concrete basins and explains the background for possible modifications to be made in a new ZTV‐ING. For example, in case of a global categorization, many components would have to be formally assigned to the exposure class XF4, from which the mandatory use of air‐entrained concrete would then be directly derived. However, differentiated considerations, considering specific boundary conditions and many years of experience, also allow the use of concretes without air entraining agents. [ABSTRACT FROM AUTHOR]

High performance precast elements for building constructions – A contribution to the disruptive change of mineral components Concrete (NPC) is the most commonly used building material worldwide, which also has great development potential in terms of resource and energy efficiency as well as in terms of production, recyclability and durability. A possible further development that sums up this development potential is high‐performance precast elements from concrete and steel composit as well as from the material ultra‐high‐performance concrete (UHPC). When used appropriately to the material, savings of up to 85 % in resources and up to 65 % of GWP (GWP = E = CO2e) can be achieved. With appropriate application, an immediate reduction in resource and GWP‐ consumption in new buildings would be possible. The high durability of the UHPC material and the use of modular prefabrication in production add to the advantages. We can only meet the stringent requirements of the Intergovernmental Panel on Climate Change (IPCC) via the residual budget available for the industry up to climate neutrality if we are ready to immediately implement measures for resource and climate efficiency with the technologies that are already available. It will sometimes be a major task of politics to quickly implement these requirements for the construction industry through regulations. The embodied energy (PENRT) of our constructed buildings already accounts for approx. 25 % of global CO2e consumption with a strong upward trend and we builders, especially planners and prefabricated part manufacturers, are required to select the material, the structure and the production of components to make an immediate contribution. This report uses innovative high‐performance prefabricated structural elements to show the advantages over conventional reinforced concrete construction in terms of recyclability, durability and potential savings in resource and GWP consumption for roof, ceiling and wall elements as well as staircase and balcony elements. Concrete amounts of savings can be specified in t CO2e on the basis of a concrete apartment prototype that is manufactured with these high‐performance prefabricated parts. The implementation of existing technologies can lead to significant changes in the construction industry and requires choose, want, courage and repeat on the part of those involved. In this regard, we are all called upon to make a contribution together. [ABSTRACT FROM AUTHOR]

Experimental investigations on the durability of intumescent coatings Intumescent coatings are used in structural fire protection to improve the fire resistance of steel structures. Beside structural fire resistance also aesthetic demands can be fulfilled. The profile‐following application and the low dry film thickness of the products make it possible to maintain the filigree appearance of steel structures. In addition to the thermal protection effect, the durability of the coating must also be ensured. The assessment methods available at European level by EAD 350402‐00‐1106 aim to a service life of ten years. Test methods for a longer period are not described. This paper presents experimental investigations on the influence of weathering on the expansion behaviour, the thermal performance and the reactions taking place during foaming in case of fire. The tests were carried out on a water‐based and an epoxy resin‐based intumescent coating. The research results were obtained in the IGF research project 20470 N. [ABSTRACT FROM AUTHOR]

Effect of preconditioning on the freeze‐thaw resistance of concrete The pore system in concrete, consisting of gel and capillary pores, influences its water absorption capacity and thus directly also the freeze‐thaw resistance. Different exposure conditions in the young age of concrete have a significant influence on the formation of the pore system. To clarify the role of preconditioning on the forming pore structure and thus the freeze‐thaw resistance of concrete, specimens were preconditioned at different relative humidities and then tested according to the CDF test. It was found that the freeze‐thaw resistance of specimens with a water‐cement ratio of 0.40 depended significantly on the degree of hydration near the surface. This varied due to the different humidities during preconditioning. The decisive criterion for the freeze‐thaw resistance of the specimens with a water‐cement ratio of 0.55 is the degree of water saturation due to the distinctive capillary pore system of this w/c. The degree of water saturation of the specimens with a water‐cement ratio of 0.55 is also a decisive criterion for the freeze‐thaw resistance. Specimens with a particularly distinct capillary pore system possessed very high amounts of weathering. Finally, a prediction model based on an artificial neural network is presented. This model is able to predict the weathering of mortar samples in the CDF test on the basis of moisture measurements before freeze‐thaw exposure. [ABSTRACT FROM AUTHOR]

Durable multi‐storey and underground car parks The DBV guide to good practice „Multi‐storey and Underground Car Parks" with the supplementary DBV booklets 42 and 46 are among the publications in the extensive DBV publication collection, devoted to the subject of parking structures. The aim of these publications is, among other things, to provide practitioners working in the field of designing and execution with planning principles, solutions for details, implementation instructions and, above all, measures to ensure adequate durability of parking structures. It summarizes many guidelines for the design and construction of parking structures that have proven their worth in practice. An updated 2022 reprint of the DBV guide to good practice „Multi‐storey and Underground Car Parks" based on the January 2018 version will be published shortly. This article presents the DBV publications, their contents, objectives and interrelation and explains the changes made in the updated DBV guide to good practice reprint. [ABSTRACT FROM AUTHOR]

Durable protection against corrosion – glass fiber reinforced polymer (GFRP) as reinforcement for raft foundation slabs in underground car parks Corrosion damage to parking decks and underground garages is an expensive and unpleasant ongoing issue for operators. When water and air penetrate the reinforced concrete components through cracks in the concrete to the reinforcing steel, it begins to corrode. The chloride ingress, which is present in almost every parking structure, e. g. from de‐icing salt used in winter, increases and/or initiates this corrosion. Raft foundation slabs are most frequently affected, as they are subjected to particularly high mechanical stress. As a preventive measure, such structures are protected from corrosion by high‐maintenance surface coatings. A durable and economical solution is to use glass fiber reinforced polymer reinforcement. This is high‐strength, chemically resistant and corrosion‐resistant, which avoids avoids high maintenance costs. [ABSTRACT FROM AUTHOR]

Climate Compatibility as a Criterion for the Design and Performance of Concrete illustrated by the Example of an ÖBB Small Animal Passage Concrete is the world's most widely used building material and is preferred for infrastructure construction inter alia due to its high performance, versatility and durability. Its production and use, however, generates significant amounts of greenhouse gas emissions (CO2eq). Consequently, any reduction of CO2eq of the building material contributes to achieving the societal goal of CO2 neutrality. In this paper, a small animal passage of an ÖBB railway line is used as an example to show how climate compatibility or CO2‐equivalents (kg CO2eq/m3) are directly integrated into the mix design. It is also explained how the essential performance characteristics of climate‐compatible concretes – in addition to the CO2‐equivalents, in particular their early strength and durability – can be considered and optimised in their entirety. For this purpose, performance‐based concepts are applied for the optimisation of binders with combined additives and for the verification of durability. Furthermore, experiences with the realization, testing and quality assurance of CO2eq‐reduced concrete in comparison to equivalent standard concrete will be reported. [ABSTRACT FROM AUTHOR]

The practice of early, costly repairs or replacement buildings, which has been common in reinforced concrete construction for decades, allows the realization to mature that the reinforced concrete material for heavily exposed buildings in the infrastructure sector must be replaced by a more efficient material and its construction method. In materials research in the 21st century, the UHPC (ultra high performance concrete) has meanwhile become an obvious choice for constructive use in bridge construction and offers a wide range of options when used appropriately for the material. The construction system of the UHPC BridgefamilyIntegral is described in your design for the application of small to large bridges and thus represents a future possibility of using UHPC large prefabricated parts consistently in bridge construction. The focus is on designing material-appropriate construction. The desired target of saving both resources and CO² already in the production phase A1 to A3 should only be possible with material-appropriate construction. Another important aspect is the detailed training in order to obtain permanent bridge constructions. A system-immanent integral construction creates the prerequisites for the construction system described to be maintenance-friendly in operation. The special geometry of the construction as well as the light appearance lead to significantly lower constrained stress from load-independent effects compared to conventional bridge structures made of reinforced and prestressed concrete. In a final consideration, the advantages of this construction method are summarized again and an outlook for future applications is given. [ABSTRACT FROM AUTHOR]

The article discusses the issues of increasing the durability of road-building machines. As a subject of research, friction units are considered, the details of which are made of gray iron. On the basis of a comprehensive technical and economic analysis of hardening methods for cast iron parts, it was established that chemical-heat treatment has the best combination of criteria. The methods used in practice for hardening cast irons are of little use in the conditions of repair production due to the complexity of technological processes and equipment. In addition, the thickness of the hardened layer usually does not exceed 0.3 mm. The paper discusses the main aspects of the application of new technology of surface hardening, formulated recommendations for its use, depending on the service purpose details. An assessment of the technical level of the proposed solutions compared with traditional technologies of hardening of cast iron.

The article presents materials on the study of the issue of increasing the resistance of technically complex twisted wire products-steel rope. The authors studied in detail the mechanisms and factors of formation of defects that lead to steel rope rejection. The cause abrasion and breakage of the wire strands in the locks (nodes) to couple the pusher is lack of mobility due to the lack of necessary quantity of lubricant for normal operation of a steel rope. The lubricants used in the manufacture of steel rope and its operation do not meet the requirements for durability, which leads to a decrease in the service life (loading cycles) established by the manufacturer. To solve the problem of increasing the resistance of steel ropes, the authors propose a new method of forming an antifriction powder coating based on molybdenum disulfide (MoS2) in the locks (nodes) of the coupler and on the surface of the wire by injection under pressure of compressed air antifriction powder material and fixing it on a complex surface by local hardening using a ball-rod hardener. Experimental tests of the surface layer of steel wire rope of different material coated with antifriction powder showed that the coefficient of friction is reduced from 3 to 9 times, and their wear resistance increased from 4 to 20 times. The main conclusions characterizing nanoscale pattern micro/nanoprobes the original surface of the sample, the steel wire rope of carbon steel according to GOST 1050 and GOST 14959. With anti-friction coating (MoS2), powder. From the presented drawings, the surface coated with molybdenum disulfide (MoS2) in comparison with the untreated becomes more flat, the micro-steps are rounded.

The article informs about the installation of a rack cleaning technology in the Schütt II power plant of electric utility company KELAG-Kärntner Elektrizitäts-Aktiengesellschaft. Topics discussed include its construction phase, material used in its construction, its variants and its durability benefits.

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An approaches to the study of the fatigue strength of a freight car 18-100 bogie’s side frame are under consideration in this article. There is a decline of the quality of the manufacture side frames and increase of the number of defects, which leads to an increase the number of accidents. The relationship of the stress intensity factor and crack length for different types of fatigue cracks (surface crack and full perforation) was introduced. The algorithm of a bogie with a crack fa-tigue calculation was introduced. The inhibition of crack growth under overloading was taking into account during cal-culation. The additional numerical calculation of fatigue strength was performed by the specialized software package. Some defects of bogie larger than 1 mm is unacceptable as it dramatically reduces the fatigue strength.

Copyright of Tribologie und Schmierungstechnik is the property of Narr Francke Attempto Verlag GmbH & Co.KG and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The article reflects on the evolution of dental technology over the past fifty years, emphasizing three milestones that have transformed the field. The first milestone highlights the introduction of metal ceramics, enhancing the aesthetic appearance and durability of crowns and bridges. The second milestone discusses the advent of CAD/CAM technology, enabling more individualized and precise dental solutions. The third milestone explores the impact of 3-D printing and intraoral scanning.

Copyright of Elektronik Industrie is the property of Hüthig GmbH and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The article provides a preview of multiple products related to dental technology and materials used in dentistry for various applications, including "SprintRay EU High Impact Denture Base," "SprintRay EU Temporary Crown & Teeth Material," and "SprintRay Surgical Guide 3" from Weiterstadt.

Copyright of Zeitschrift für Konfliktmanagement is the property of De Gruyter and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Elektronik Industrie is the property of Hüthig GmbH and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)