(節(jié)選）外文翻譯(英文)輕質(zhì)陶?；炷磷鳛橐环N燃油艙船舶的額外保護

1、14 POLISH MARITIME RESEARCH, Special issue 2008INTRODUCTION Concrete is one of the most commonly applied materials for building structures. It has achieved its popularity due to specific properties which allow for its

2、very wide application. The concrete applied directly in situ, the so called ‘ fresh concrete’is characterized by a high plasticity and workability, that makes it possible to form building structures almost without any

3、 limits. The concrete formed in the structure hardens very fast due to its hydratation processes, that gives appropriate strength and durability to building objects. A relatively simple way of concrete manufacturing,

4、accessibility of its components, as well as wide range of its applications conditioned by many kinds of the material, have resulted in that the concrete is the most frequently used material for building structures. Su

5、ch situation entails fast development of concrete technology. Many reserach projects aimed at improvement and modification of basic features of concrete are carried out worldwide. This is a material which continuousl

6、y undergoes evolution, trying to cope with more and more sophisticated architectural requirements. Concrete is a composite which is mainly formed of three components: binder, aggregate and water. Chemical admixtures

7、and mineral additives, cut steel wires, natural and artificial fibres are also applied to it. After mixing the components together, a concrete mixture is obtained in the form of a viscous –plastic –solid body which is

8、 transformed into a solid body changing its features during further hardening (curing) process. The components of concrete of many types and classes can be found, that makes it possible to get mixtures of very differe

9、nt features and applications. The features can be additionally modified by introducing chemical admixtures and mineral additives. The so produced concrete is capable of transferring very large structural loads (high

10、strength concretes), providing high durability for engineering objects (high durability concretes) Lightweight ceramsite concrete used as an additional protection of fuel oil tanks on shipsMarcin Je?ewski Cezary Krasow

11、ski Barg M.B. Gdańsk, Sp. z o.o.ABSTRACTIntroduction of the semi-elastic barrier into ship fuel tanks requires of use of core material which will play role of carrier for elastic, fuel resistant layer. Such core materia

12、l should be ligth, non reactive with water and fuel, fire resistant, corrosion neutral and finally easy applicable and relatively cheap. In paper the different problems like components, preparation, application as well

13、 as surface treatment for using of the light concrete as core material are presented.Keywords: light concrete, core material, fuel tank protectionor filling structural spaces (lightweight concretes), as well as it is s

14、uitable for many other applications in contemporary building industry. The diversity of concrete mixtures, achieved by appropriate selection of particular types of main components, admixtures and additives, makes that

15、 their utility features begin drawing attention of other branches too, not only of building industry. One of the attempts to using the concrete features to other applications is the project of an additional protection

16、 layer made of concrete for ship fuel oil tanks and cargo tanks on tankers. This is a layer intended for separating ship’ s structure from a polyurethane coating which constitutes also a protective element of tanks.

17、In the project the use is made of a relatively high strength of concrete associated with its rather low volumetric density (important for overall weight of ship), as well as its full fire resistance and durability imp

18、lying a long service life. This paper presents an approach to implementation of concrete engineering and materials science to designing a concrete mixture which complies with criteria of the project. Below, ways of se

19、lection of particular components of the concrete, its manufacturing and material application, are presented.SELECTION OF LIGHTWEIGHT CONCRETE COMPONENTSOne of the main features of concrete mixture deciding on selecti

20、on of its components was its volumetric density. With a view of minimization of additional weight of ship one tried to obtain a concrete of as low volumetric density as possible with maintained maximum values of its s

21、trength and durability parameters. A lightweight aggregate concrete distinguished –out of other kinds of concrete - by a relatively low volumetric POLISH MARITIME RESEARCH Special Issue 2008; pp. 14-17 DOI: 10.2478/v1

22、0012-007-0071-4Lightweight ceramsite concrete used as an additional protection of fuel oil tanks on ships16 POLISH MARITIME RESEARCH, Special issue 2008In the case in question the super-plastificator admixture based on

23、multi-carboxilate was applied. As a result of the application of the admixture, liquidity of the mixture - hence also its workability - was increased, and amount of applied water was lowered at maintained cement conte

24、nt, that led to a greater concrete strength. Such kind of admixture is intended for cements of fast rising strength. For manufacturing the concrete mixture, tap water satisfying all relevant requirements according to

25、 PN-EN-standards was used. MANUFACTURING THE LIGHTWEIGHT CERAMSITE CONCRETEGeneral recommendationsIn accordance with a working recipe determined in advance, particular components of concrete are dosed in the followin

26、g order : aggregate, possible fly-ash or natural sand additive, 1/2-3/4 amount of working water, cement and the remaining part of water. If aerating –plastifying additives are used their solution should be dosed last

27、–after initial mixing the components. Before dosing the ceramsite its moisturing is recommended (using abt. 1/2 amount of working water). In the case of cement its dosing should be done by weighing, and in the case o

28、f aggregates –by weighing or volume measuring after determination value of bulk density of a given aggregate. Attention should be paid to water dosing. Changeable initial wetness of aggregate and progressing process o

29、f its moisturing can make it difficult to obtain a proper consistence of the mixture, which may require to be corrected. The mixing should be performed mechanically –the best way is to apply forced, concurrent or back

30、ward mixing. Time of mixing should be not shorter than 3 min. If chemical aerating and plastifying additives are used the mixing time should be longer. The ceramsite aggregate concrete mixtures which have less dense

31、consistence, can be susceptible to segregating the components. Hence their transport should be performed in such way as not to cause segregation and changes in their composition. A seperate problem is the mixture’ s t

32、ransport by pumping. High absorption capacity of aggregate makes that a part of working water - under pressure - developed during concrete pumping –is pressed into aggregate volume, that results in densification of t

33、he pumped mixture and consequently - blocking the pipelines. To make ceramsite concrete easy for pumping the aggregate should be mositured in advance and the concrete of a good workability should be designed. Applica

34、tion of the ceramsite concrete mixture should be made uniformly over the whole surface of the form, and the throwing of the mixture from a greater height and placing of the concrete in the form of cone should be avoid

35、ed as it may lead to partial segregation of the mixture. Application of aerating admixtures prevents the concrete mixture from segregation. Complete filling the form by the mixture should be finished before 30 min pa

36、ssing from the end of the mixing of components. Densification of the mixture should be done by using immersing vibrators of high frequencies and low amplitudes of vibration.RecipeThe below given content of 1 m3 of the

37、 concrete mixture was determined as a result of application of the general principles of concrete mixture designing with taking into account specificity of application of lightweight aggregates as well as results of v

38、erification of preliminary design assumptions by laboratory tests : CEM I 32.5 cement –350 kg Ceramsite –450 kg, fractions from 0-20 mm Fly-ash –150 kg Water –250 l Super-plastificator –0.3 % of cement mass.The a

39、bove given recipe was prepared for ceramsite concrete of a firm structure. Degree of filling the void spaces between aggregate particles by cement slurry should be not smaller than 85 %. The concrete of firm structure

40、 –in contrast to that having cavities or semi-firm one –is characterized by a greater compressive strength and greater workability, obtainable especially after adding fly-ashes and plastifying additives. Elaboration

41、of a precise recipe for lightweight aggregate concrete mixture brings about certain difficulties. Because of high absorbability of lightweight aggregate as well as its suceptibility to segregation such recipe should b

42、e currently verified during production process and introduction of necessary corrections, mainly to amount of dosed water, should be possible.Manufacturing processIn the case in question the first step in manufacturin

43、g of concrete mixture was to soak the aggregate in about 50% amount of working water. Next, in line with the above mentioned principles of sequencing the component addition, the components were mixed in a mixer up to

44、 the state of a uniform, non-separating, dense plastic mass. The remaining amount of working water was then added under continuous control of the slurry’ s consistence in order to prevent the mixture from excessive l

45、iquefaction, that could make correct application of the concrete impossible and its segregation easier. After obtaining its appropriate consistence and sufficient degree of mixing its components, the mixture was place

46、d onto a ship plating element. For the mixture placing the immersing vibrators were applied in order to obtain its uniform distribution. Correctly manufactured concrete well spreads, does not leave void spaces and do

47、es not segregate or stratify its components. Fig. 3. Application of the concrete into the ship bottom structure The so prepared concrete mixture showed –during laboratory tests –the values of volumetric density in the r

48、ange of 1100 –1200 kg/m3, and the values of the compressive strength after 28 days of curing - in the range of 12-14 MPa. Application of the pozzolan fly-ash additive makes it possible to expect a further rise of the