Monitoring the Degradation of UHPC Boards

2015 ◽  
Vol 752-753 ◽  
pp. 518-521
Author(s):  
Michaela Kostelecká
Keyword(s):  
Hot Water ◽  
Minimum Thickness ◽  
Conventional Concrete ◽  
Design Elements ◽  
Water Test ◽  
New Type ◽  
Steel Armature ◽  
Cover Thickness ◽  
The Cost ◽  
Concrete Elements

In this article the hot water test is presented on thin UHPC slabs that are reinforced by a new type of armature. It is a textile armature, which should replace the classic metal (steel) armature. Textile armature should not only reduce the cost of production, but, because it is not susceptible to corrosion as conventional steel armature, panels can be designed with significantly less cover thickness in achieving similar or longer lifetime of these elements. The combination of UHPC concrete with a minimum thickness of cover and textile armature allows design elements weighing up to 70 % lower compared to conventional concrete elements with conventional armature. This can achieve significant savings and benefits not only in economic aspects, but also in environmental aspects.

To Monitoring the Degradation of UHPC Boards with Textiles Armatures

2015 ◽  
Vol 732 ◽  
pp. 381-384
Author(s):  
Michaela Kostelecká
Keyword(s):  
Hot Water ◽  
Minimum Thickness ◽  
Conventional Concrete ◽  
Design Elements ◽  
Water Test ◽  
New Type ◽  
Steel Armature ◽  
Cover Thickness ◽  
The Cost ◽  
Concrete Elements

In this article the hot water test is presented on thin UHPC slabs that are reinforced by a new type of armature. It is a textile armature, which should replace the classic metal (steel) armature. Textile armature should not only reduce the cost of production, but, because it is not susceptible to corrosion as conventional steel armature, panels can be designed with significantly less cover thickness in achieving similar or longer lifetime of these elements. The combination of UHPC concrete with a minimum thickness of cover and textile armature allows design elements weighing up to 70 % lower compared to conventional concrete elements with conventional armature. This can achieve significant savings and benefits not only in economic aspects, but also in environmental aspects.

Monitoring the Degradation of UHPC Boards with Textiles Armatures

2015 ◽  
Vol 1106 ◽  
pp. 148-151
Author(s):  
Michaela Kostelecká
Keyword(s):  
Glass Fibre ◽  
Hot Water ◽  
Glass Fabric ◽  
Alkali Resistance ◽  
Reference Set ◽  
Water Test ◽  
New Type ◽  
Fibre Mesh

In this article the degradation using hot water test is presented on thin UHPC slabs that are reinforced by a new type of armature. It is a textile armature. There were used the following types of textile armature: glass fibre mesh fabric, 2D glass fabric and 3D glass fabric. All textiles armatures were alkali-resistance. The degradation was carried out using the standard ČSN EN 12467. The specimens were divided into two sets. One set was the reference set and second set was carried the set exposed in hot water. The results were determined by comparing these two sets.

scholarly journals Optimal Renovation Strategies through Life-Cycle Analysis in a Pilot Building Located in a Mild Mediterranean Climate

2021 ◽  
Vol 11 (4) ◽  
pp. 1423
Author(s):  
José Manuel Salmerón Lissen ◽  
Cristina Isabel Jareño Escudero ◽  
Francisco José Sánchez de la Flor ◽  
Miriam Navarro Escudero ◽  
Theoni Karlessi ◽  
...  
Keyword(s):  
Life Cycle ◽  
Life Cycle Cost ◽  
Mediterranean Climate ◽  
Building Envelope ◽  
Economic Life ◽  
Hot Water ◽  
Optimal Solutions ◽  
Building Stock ◽  
Existing Building ◽  
The Cost

The 2030 climate and energy framework includes EU-wide targets and policy objectives for the period 2021–2030 of (1) at least 55% cuts in greenhouse gas emissions (from 1990 levels); (2) at least 32% share for renewable energy; and (3) at least 32.5% improvement in energy efficiency. In this context, the methodology of the cost-optimal level from the life-cycle cost approach has been applied to calculate the cost of renovating the existing building stock in Europe. The aim of this research is to analyze a pilot building using the cost-optimal methodology to determine the renovation measures that lead to the lowest life-cycle cost during the estimated economic life of the building. The case under study is an apartment building located in a mild Mediterranean climate (Castellon, SP). A package of 12 optimal solutions has been obtained to show the importance of the choice of the elements and systems for renovating building envelopes and how energy and economic aspects influence this choice. Simulations have shown that these packages of optimal solutions (different configurations for the building envelope, thermal bridges, airtightness and ventilation, and domestic hot water production systems) can provide savings in the primary energy consumption of up to 60%.

Sorting permutations by fragmentation-weighted operations

2020 ◽  
Vol 18 (02) ◽  
pp. 2050006 ◽  
Author(s):  
Alexsandro Oliveira Alexandrino ◽  
Carla Negri Lintzmayer ◽  
Zanoni Dias
Keyword(s):  
Approximation Algorithms ◽  
Computational Biology ◽  
Cost Function ◽  
Traditional Approach ◽  
Upper Bounds ◽  
Evolutionary Distance ◽  
Lower And Upper Bounds ◽  
Approximation Factor ◽  
New Type ◽  
The Cost

One of the main problems in Computational Biology is to find the evolutionary distance among species. In most approaches, such distance only involves rearrangements, which are mutations that alter large pieces of the species’ genome. When we represent genomes as permutations, the problem of transforming one genome into another is equivalent to the problem of Sorting Permutations by Rearrangement Operations. The traditional approach is to consider that any rearrangement has the same probability to happen, and so, the goal is to find a minimum sequence of operations which sorts the permutation. However, studies have shown that some rearrangements are more likely to happen than others, and so a weighted approach is more realistic. In a weighted approach, the goal is to find a sequence which sorts the permutations, such that the cost of that sequence is minimum. This work introduces a new type of cost function, which is related to the amount of fragmentation caused by a rearrangement. We present some results about the lower and upper bounds for the fragmentation-weighted problems and the relation between the unweighted and the fragmentation-weighted approach. Our main results are 2-approximation algorithms for five versions of this problem involving reversals and transpositions. We also give bounds for the diameters concerning these problems and provide an improved approximation factor for simple permutations considering transpositions.

RENEWABLE ENERGY INTEGRATION FOR HOT WATER SUPPLY AND HEATING OF BUILDINGS

2021 ◽  
pp. 3-12
Author(s):  
Yu. Selikhov ◽  
K. Gorbunov ◽  
V. Stasov
Keyword(s):  
Solar Energy ◽  
Heat Production ◽  
Heat Supply ◽  
Alternative Energy ◽  
Fossil Fuel ◽  
Heat Pumps ◽  
Climatic Conditions ◽  
Economic Feasibility ◽  
Hot Water ◽  
The Cost

Solar energy is widely used in solar systems, where economy and ecology are combined. Namely, this represents an important moment in the era of depletion of energy resources. The use of solar energy is a promising economical item for all countries of the world, meeting their interests also in terms of energy independence, thanks to which it is confidently gaining a stable position in the global energy sector. The cost of heat obtained through the use of solar installations largely depends on the radiation and climatic conditions of the area where the solar installation is used. The climatic conditions of our country, especially the south, make it possible to use the energy of the Sun to cover a significant part of the need for heat. A decrease in the reserves of fossil fuel and its rise in price have led to the development of optimal technical solutions, efficiency and economic feasibility of using solar installations. And today this is no longer an idle curiosity, but a conscious desire of homeowners to save not only their financial budget, but also health, which is possible only with the use of alternative energy sources, such as: double-circuit solar installations, geothermal heat pumps (HP), wind power generators. The problem is especially acute in the heat supply of housing and communal services (HCS), where the cost of fuel for heat production is several times higher than the cost of electricity. The main disadvantages of centralized heat supply sources are low energy, economic and environmental efficiency. And high transport tariffs for the delivery of energy carriers and frequent accidents on heating mains exacerbate the negative factors inherent in traditional district heating. One of the most effective energy-saving methods that make it possible to save fossil fuel, reduce environmental pollution, and meet the needs of consumers in process heat is the use of heat pump technologies for heat production.

scholarly journals TO DETERMINATION OF THE CRACKING MOMENT FOR BENDING REINFORCED CONCRETE ELEMENTS WITH ACCOUNT OF PLASTIC DEFORMATIONS OF CONCRETE IN THE TENSION AREA

2018 ◽  
Vol 3 (3) ◽  
pp. 30-38
Author(s):  
О.В. Радайкин ◽  
Oleg Radaykin
Keyword(s):  
Reinforced Concrete ◽  
Deformation Model ◽  
Conventional Concrete ◽  
Class A ◽  
Standard Calculation ◽  
Plasticity Coefficient ◽  
Concrete Elements ◽  
Nonlinear Deformation Model ◽  
Good Agreement

At the standard calculation of the cracking moment for bending reinforced concrete elements the plasticity coefficient γ is normally used, which according to SP 63.13330.2012 is 35% less than in the old SNiP 2.03.01-84*. The question arises, what is the reason for such a noticeable difference and which of the methods gives more reliable results? This article seeks to answer this question. For this purpose the physical meaning of the coefficient γ was considered in detail, with the usage of a nonlinear deformation model of a normal section. A calculation formula for γ depending on an element’s reinforcement degree was obtained, which is valid for conventional concrete of B15-B35 class. A comparison of the calculated cracking moment according to the proposed method with experiments by the other authors was carried out. A good agreement of results was observed.

scholarly journals Ultra-high-performance concrete with local high unburned carbon fly ash

DYNA ◽  
2021 ◽  
Vol 88 (216) ◽  
pp. 38-47
Author(s):  
Joaquín Abellán García ◽  
Nancy Torres Castellanos ◽  
Jaime Antonio Fernandez Gomez ◽  
Andres Mauricio Nuñez Lopez
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
High Performance ◽  
High Performance Concrete ◽  
Unburned Carbon ◽  
High Tech ◽  
Ultra High Performance Concrete ◽  
Conventional Concrete ◽  
The Cost

Ultra-high-performance concrete (UHPC) is a kind of high-tech cementitious material with superb mechanical and durability properties compared to other types of concrete. However, due to the high content of cement and silica fume used, the cost and environmental impact of UHPC is considerably higher than conventional concrete. For this reason, several efforts around the world have been made to develop UHPC with greener and less expensive local pozzolans. This study aimed to design and produce UHPC using local fly ash available in Colombia. A numerical optimization, based on Design of Experiments (DoE) and multi-objective criteria, was performed to obtain a mixture with the proper flow and highest compressive strength, while simultaneously having the minimum content of cement. The results showed that, despite the low quality of local fly ashes in Colombia, compressive strength values of 150 MPa without any heat treatment can be achieved.

scholarly journals SOLAR RADIATION PROTECTION SYSTEM WITH SIMULTANEOUS HOT WATER SUPPLY

2020 ◽  
Author(s):  
І. Puhoviy ◽  
М. Makhrov
Keyword(s):  
Solar Energy ◽  
Energy Savings ◽  
Electrical Power ◽  
Warm Season ◽  
Hot Water ◽  
Air Conditioner ◽  
Domestic Water ◽  
Environmental Friendliness ◽  
Additional Advantage ◽  
The Cost

Problems. Windows in the summer let through a large amount of solar energy into the room, which causes an additional cost of cooling the air by conditioning. It is known that the limit of comfort is the temperature of 26 oC. To reduce the temperature, use air conditioners, which are required 0,3...0,5 kW of electrical power for 10 m2 of housing. The study deals with the capture of solar energy by water and its use for domestic water purposes (DHW). The goal of the research. Experimental verification of patented developments and calculations of hot water quantity obtained per day, energy savings and economic indicators. Methods of implementation. Experiments were conducted on the south window of the room, with water pumping by a pump and periodic measurement of air and water temperatures at the outlet of the system by mercury thermometer. The calculations were performed using the methods developed by the authors. The studies were conducted within three days of November. The temperature inside ranged a room from 19 to 23 °C. The system was operated in circulating mode on a water battery tank located below the absorber. Isolation of the absorber from the side of the room was made of a transparent food film. Research results. Water temperature reached 45 °C per 1,5-2 hours. Water consumption is enhanced by the thermosiphon effect when water moves from the bottom up. On a clear day of spring and autumn, you can heat for 50-70 % more water than the average for the average day of months of the warm season. For preparing DHW with 1 m2 of absorber, it is possible to get 45-50 kW∙h of heat for each month from March to September, taking into account cloudiness. The savings from the use of hot water and from reducing the consumption of electricity in the air conditioner are calculated. Conclusions. The payback period of the system, taking into account the cost of the heat for DHW and electricity savings for an electric air conditioner, is approximately 4-5 years. The cost of the system is close to the cost of a home air conditioner, for a premise with a single window oriented south. To the energy-saving factor, an additional advantage is the environmental friendliness of the system compared to the air conditioner.

scholarly journals Personalised Formwork – scientific approach for new solution variants

2019 ◽  
Vol 290 ◽  
pp. 04005
Author(s):  
Raluca Diaconu ◽  
Paul Dan Brindasu
Keyword(s):  
Elastic Material ◽  
Experimental Tests ◽  
Low Resistance ◽  
Synthetic Rubber ◽  
Material Cost ◽  
Creative Methods ◽  
Scientific Approach ◽  
New Type ◽  
The Cost

Application of personalised formwork is of most interest for architects and engineers now-a-days. Although a required demand when designing special constructions, there is little data and material solutions for this case. The cost and domain of application are of most importance in determining new solutions for concrete formworks. To contribute to these requests (a wider usage domain, productive material cost and maintenance), a personalised formwork concept is presented. The idea of reusing the formwork led to an elastic material – membrane (thermoset elastomers, synthetic rubber) with a punching tie-rod solution in order to obtain any architectural shape desired. This first solution was evaluated taking into account different membrane thicknesses. Several experimental tests denoted that the named chosen membrane variants are of low resistance for pouring a concrete architectural slab, so new solutions were discussed. Hence, a re-analysis of the PLM steps was achieved in order to find an answer for the encountered problem. By using creative methods, we obtained a second solution and put it to test. The attained results are used in order to establish the area of workability, to enlarge the tested domain and to assess the sustainability of a new type of personalised formwork

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