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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Sustainable urban pavement for cities affected by El Niño using porous concrete

Aguirre, B., Anchiraico, M., Rodríguez, J., García, F. 05 February 2021 (has links)
The El Niño phenomenon is caused by the change in atmospheric pressures, which produce the accumulation of hot surface waters on the eastern flank of the Pacific Ocean; causing intense rainfall that runs over the surface affecting the urban drainage of the city due to the lack of a permeable pavement; porous concrete allows infiltration of surface water runoff through its pores. The present investigation evaluates porous concrete in the range of w/c relationships of 0.30 and 0.32; the results indicate that the compressive strength, flexural strength and permeability coefficient increase; and that the surface runoff, cost, water footprint and carbon footprint are lower than conventional concrete.
2

Putų cementbetonio savybių tyrimas / Research of the foam cement concrete

Rožėnas, Paulius 22 July 2008 (has links)
Šio magistrantūros studijų baigiamojo darbo tikslas yra išnagrinėti autoklavinio poringojo betono savybes į kurio mišinio sudėtį dedama akytojo betono gamybos atliekų. Akyta cementbetonio struktūra sudaryta naudojant putas. Darbas susideda iš teorinės ir eksperimentinės dalių. Teorinėje dalyje atlikta literatūros analizė, pateiktos bendrosios žinios apie akytuosius betonus, jų žaliavas, klasifikaciją bei kai kurias fizikines ir mechanines savybes. Autoklavinis putų cementbetonis nagrinėjamas kaip viena iš akytojo betono atmainų. Nagrinėjami putokšliai, lyginamos iš jų išplaktų putų savybės. Aptariamas akyto betono atliekų panaudojimas gaminant putų cementbetonį. Šiuo tikslu buvo nagrinėjami įvairūs literatūros šaltiniai, lyginamos įvairių autorių sukauptos žinios ir tyrimų rezultatai. Eksperimentinėje dalyje tiriamos putokšlių ir iš jų išplaktų putų savybės. Nagrinėjamas akytojo betono gamybos atliekų panaudojimas. Aprašoma putų ir betono atliekų kiekio įtaka putų cementbetonio tankiui, gniuždomajam stipriui ir gaminių struktūrai. / The point of this postgraduate studies final work is research the autoclaved porous concrete characteristics, in whose composition is waste of porous concreat. The porous structure is make by foam. This work consists of theoretical and experimental parts. The teoretical part of this work consist of literature analysis, there are given general knowledge about porous concrete, materials, classifications, physical and mechanical characteristics. The autoclaved foam cement concrete was researched like one of the active concrete species. There were analysed foamers, comparables internals of foams. Considerating the waste of porous concreat utilization maiking foam cement concrete. For this purpose were researched various information publikations, compared the cumulated knowledges and experimental results of various authors. In experimental part are described foamers and from their mades foams characteristics. Reserching the waste of porous concreat utilization. Described quantity of foams and concrete wastes influence to density, strength and composition of foam cement concrete.
3

Pore Structure Dependence of Transport and Fracture in Pervious Concretes

January 2013 (has links)
abstract: Properties of random porous material such as pervious concrete are strongly dependant on its pore structure features. This research deals with the development of an understanding of the relationship between the material structure and the mechanical and functional properties of pervious concretes. The fracture response of pervious concrete specimens proportioned for different porosities, as a function of the pore structure features and fiber volume fraction, is studied. Stereological and morphological methods are used to extract the relevant pore structure features of pervious concretes from planar images. A two-parameter fracture model is used to obtain the fracture toughness (KIC) and critical crack tip opening displacement (CTODc) from load-crack mouth opening displacement (CMOD) data of notched beams under three-point bending. The experimental results show that KIC is primarily dependent on the porosity of pervious concretes. For a similar porosity, an increase in pore size results in a reduction in KIC. At similar pore sizes, the effect of fibers on the post-peak response is more prominent in mixtures with a higher porosity, as shown by the residual load capacity, stress-crack extension relationships, and GR curves. These effects are explained using the mean free spacing of pores and pore-to-pore tortuosity in these systems. A sensitivity analysis is employed to quantify the influence of material design parameters on KIC. This research has also focused on studying the relationship between permeability and tortuosity as it pertains to porosity and pore size of pervious concretes. Various ideal geometric shapes were also constructed that had varying pore sizes and porosities. The pervious concretes also had differing pore sizes and porosities. The permeabilities were determined using three different methods; Stokes solver, Lattice Boltzmann method and the Katz-Thompson equation. These values were then compared to the tortuosity values determined using a Matlab code that uses a pore connectivity algorithm. The tortuosity was also determined from the inverse of the conductivity determined from a numerical analysis that was necessary for using the Katz-Thompson equation. These tortuosity values were then compared to the permeabilities. The pervious concretes and ideal geometric shapes showed consistent similarities betbetween their tortuosities and permeabilities. / Dissertation/Thesis / M.S. Civil Engineering 2013
4

Mateřská škola / Kindergarden

Zlesáková, Aneta January 2019 (has links)
The aim of diploma thesis is a design project documentation of kindergarden in the construkction phase. The task was to design the most appropriate solution all of building structures in terms of construction and thermal engineering. The kindergarten will serve for education for children from 3 to 6 years old. In object are designes three departments. Individual departments are designes for total capacity 20 children. In the kindergarten there will lbe heating or preparation of only cold dishes. The kindergarten is designed single-storey with construct hight 4,25 m. Southern part of the building, where it is located ondividual departments, is designed breathable fasade. Zhe main entrance to the object is situated to the east side. Construction systém of the object is bricked from silicon-based porous concrete blocks. The roof is designed flat, vegetative. Filling of holes is made of wood-aluminum.
5

Attainable Compressive Strength Of Pervious Concrete Paving Systems

Mulligan, Ann Marie 01 January 2005 (has links)
The pervious concrete system and its corresponding strength are as important as its permeability characteristics. The strength of the system not only relies on the compressive strength of the pervious concrete but also on the strength of the soil beneath it for support. Previous studies indicate that pervious concrete has lower compressive strength capabilities than conventional concrete and will only support light traffic loadings. This thesis investigated prior studies on the compressive strength on pervious concrete as it relates to water-cement ratio, aggregate-cement ratio, aggregate size, and compaction and compare those results with results obtained in laboratory experiments conducted on samples of pervious concrete cylinders created for this purpose. The loadings and types of vehicles these systems can withstand will also be examined as well as the design of appropriate thickness levels for the pavement. Since voids are supposed to reduce the strength of concrete 1% for every 5% voids(Klieger, 2003), the goal is to find a balance between water, aggregate, and cement in order to increase strength and permeability, two characteristics which tend to counteract one another. In this study, also determined are appropriate traffic loads and volumes so that the pervious concrete is able to maintain its structural integrity. The end result of this research will be a recommendation as to the water-cement ratio, the aggregate-cement ratio, aggregate size, and compaction necessary to maximize compressive strength without having detrimental effects on the permeability of the pervious concrete system. This research confirms that pervious concrete does in fact provide a lower compressive strength than that of conventional concrete; compressive strengths in acceptable mixtures only reached 1700 psi. Extremely high permeability rates were achieved in most all mixtures regardless of the compressive strength. Analysis of traffic loadings reinforce the fact that pervious concrete cannot be subjected to large numbers of heavy vehicle loadings over time although pervious concrete would be able to sustain low volumes of heavy loads if designed properly. Calculations of pavement thickness levels indicate these levels are dependent on the compressive strength of the concrete, the quality of the subgrade beneath the pavement, as well as vehicle volumes and loadings.
6

Pervious Concrete: A Hydrologic Analysis For Stormwater Management Credit

Spence, Joshua 01 January 2006 (has links)
Portland Cement pervious concrete's ability to permit water infiltration has encouraged its use as a stormwater management tool. However, the material has suffered historically poor support due to a number of factors, including failures due to poor mix design and improper construction techniques, concern about lesser structural strength, concern about poor long term performance due to clogging of surface pores and undefined credit for stormwater management. This study focuses on long term performances of pervious concrete parking lots and their stormwater management credit. Before stormwater management credit could be estimated, it was necessary to develop a testing device to gather information from existing pervious concrete parking lots currently in use. Eight parking lots were examined to determine the infiltration rates of the pervious concrete, as well as to verify the soil makeup beneath pavement. A total of 30 cores were extracted from pervious concrete parking lots and evaluated for infiltration rates. Three of the sites had a pervious concrete section that included a gravel reservoir. Infiltration rates were measured using the application of an embedded single-ring infiltrometer. In an attempt to provide an estimate of credit, a mass balance model was created to be used for simulation of the hydrologic and hydraulic function of pervious concrete sections. The purpose of the model is to predict runoff and recharge volumes for different rainfall conditions and hydraulic properties of the concrete and the soil. The field derived hydraulic data were used to simulate infiltration volumes and rainfall excess given a year of rainfall as used in a mass balance operated within a spreadsheet. The results can be used for assessing stormwater management credit.
7

Porous Concrete: Proposal of UA Study and Best Practices

Foster, Shiloh January 2016 (has links)
Sustainable Built Environments Senior Capstone Project / Porous concrete pavements have been used in the eastern United States to effectively manage storm water when used as an alternative to impervious surfaces. This paper reviewed a wide body of available literature and research to examine their potential to reduce runoff at the University of Arizona. This study found that their unique structural properties enable them to infiltrate and detain large volumes of water in a stone sub-base below the slab, filtering out many street related contaminants without the need to install additional infrastructure. Porous concrete surfaces may support green development in the southwest where water is both a sensitive and valuable resource. However, long-term structural durability, clogging potential due to dust, and maintenance requirements have yet to be fully understood in this region. This paper then summarizes critical factors that affect the performance of porous concrete and proposes a framework for future study to be conducted by the University of Arizona in a way that would reduce runoff to major campus roads, contribute to a better understanding of sustainable storm water management in the southwest, and demonstrate leadership in environmental stewardship.
8

Reduce, reuse, recycle & rethink assessing the sustainable and creative development of park furnishings for the Mill Creek Greenway Trail, Cincinnati, Ohio /

Hicks, Molly Erin. January 2007 (has links)
A practicum report for the degree of Master of Environmental Science, Institute of Environmental Sciences, Miami University, 2007. / Title from first page of PDF document. Includes bibliographical references (p. 63-73).
9

Motel / Motel

Šich, Pavel January 2014 (has links)
The project was prepared with complete documentation of a new Motel at the level of building construction documentation. Motel has a capacity of 25 double beds and one single bed for the disabled. Built-up area is 984,2 square meters. Enclosure is designed as a flat roof. The supporting structure of the building consists of prefabricated reinforced concrete frame. Building design emphasizes on static solution and layout, fire safety, energy saving and safety of use. Drawings were processed in software for design - AutoCad
10

Horský penzion / Mountain pension

Bačina, Jan January 2016 (has links)
This diploma thesis solves the project of four-storey, partly cellared mountain pension situated in the plant number 645/2 in the cadastral area in Deštné in Orlické hory. The building has a capacity of 44 seats to accommodate 72 persons in the restaurant and 57 persons in the wellness center. There is a wellness center with fitness room and engine room of air-conditioning system in the basement. There is an entrance hall with hotel base, restaurant, sanitary facilities and utility room with boiler room on the first floor. The second and third floor is designed for accommodation. There is an outdoor terrace of restaurant. The building has a load-bearing wall system. The load-bearing walls and the partition walls are bricked up of the porous concrete YTONG bricks and sand-lime bricks SILKA. The walls are insulated of mineral wool thickeness 200 mm and EPS Perimeter thickeness 140 mm underground section and plinth area. The ceiling structure are made of the prestressed hollow core panels spiroll thickness 250 mm and wooden beamed ceiling. There is a saddle wooden roof. The windows and the doors are made by the company Progress. The part of facade of the building is ventilated. This project is designed by the computer software ArchiCAD.

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