外文翻译-粉煤灰高性能混凝土的工程应用(适用于毕业论文外文翻译

1、辽宁科技大学本科生毕业设计第11页Project applicati on of the high-performa neecon crete of fly ashThe summary Every performa nee of this text to high-performa nee con crete of fly ash has done detailed research, and to the con crete respectively to pers on who mix of fly ash Kinds of in flue nee of performanee and

2、fly ash concrete some questions that should notice carry on analysis and discussi on in not eon struct ing.1. SummaryFly ash, as a kind of in dustrial waste material, resourcesare abundant , cheap, and eon tai n a large amount of active compositi on , it is moder n eon crete Cen tral Africa A ofte n

3、 importa nt comp onent part . The high-quality fly ash is applied to the eon crete rati on ally , not only can replace the ceme nt partly , save the fabricati on cost of the project, An d, its peculiar performa nee can be used in the eon crete of various kinds of in struct ions for use very effectiv

4、ely, improve the performa nee of the eon crete, It is the ideal in the high-performa nee eoncrete that admixes the material . Among it is at eoncrete not modern, whose name is already with cement in fly ash, collect material , water , admixture and Kind is important, become a comp onent part in eon

5、crete. Fly ash high-performa nee eon crete regard durability as main goal go on desig n mix Con geal the soil . It regards excelle nt durability (in stead of the high strength) as the main characteristic , that is to say, eoncrete capital of any grade of intensity Can make into the high durability e

6、oncrete .In order to reach high durability, the performanee that the fly ash eoncrete should possess is: Mixing the state newly well Work ,n amely, without ema nati ng, secreti ng by water, so that shap ing the eve n , closely knit by mobility, harde n not shri nking subsid ing early water and Water

7、 shri nk light, warm to rise low, harden course is it dwindle to do, in order to reach having the initial crack, the permeability after harde nning is low.2. function ” and effect of the fly ash are fly ash material tech no logy and applicati on foun dati on of the project.Mix and add the powder of

8、the eoncrete Coal ash, in eonformity with understanding that the fun cti on of the fly ash is made overallly, by volca nic ash react and econo mic comp onent part gen eral to fly ash orig in ally Read , expa nd tech no logical con scious ness of fly ash effect to , make fly ash fun cti on can serve

9、performa nee of con crete improve with quality raisi ng better. The role in con crete of fly ash has the followi ng several poi nts:(1) . Shape effect: It is spongy vitreous body , little pearl of silicate glass of alu minium that the main mi neral of the fly ash makes up , smooth the body surface o

10、f these spherical glass, the grain size is thi n, the quality is pre-press ing, in side smaller tha n the surface area, the stre ngth of absorb ing to water is small, this line of physical characteristics, reduce con crete rub obstructio n in side , favorable to improveme nt , con crete of mobility

11、not merely; And, have reduci ng water fun cti on in various degree on the con crete;(2) . Active effect: The active compositi on SiO2 of the fly ash and water result of AI2O3 and cement react in a situation that there is water, producing water silicic acid calcium (C-S-H ) and water sour calcium (C-

12、A-S-H ) of sulphur alumi nium, these resp on ses n early all go on in the grout hole, water that produce result pack , cut apart the heavy origi nal hole , make the hole thinning, can reduce the hole rate within the concrete , change the hole structure , improve gluei ng the fun ctio n of formi ng o

13、f con crete every comp onent part ;(3) . Collect the material effect a little: Very small particle of fly ash eve n to is it among cement particle , pack the hole to distribute, play a role in getting to thinning hole , mean while , preve nt glue ing gatheri ng each other of the ceme nt particle, an

14、d make it in state of dispers ing , help water of the mixture to react, the fly ash will not be totally with react ing with water result of the ceme nt, can keep its collect ing the material effect a little for a long time ;(4) . Effect of the in terface: It is the weak link in the con crete structu

15、re to collect the in terface betwee n the material and ceme nt stone, width of tran siti on area as water for dust than, collect there aren m aterial , transition area have than grout body more, heavy hole. Mixi ng can reduce the regi onal width of the tran siti on to add the fly ash , i nterfere Ca

16、 (OH ) orie ntati on of 2 crystal in the tran siti on area, improve the inten sity of in terface and den sity in the con crete.(5) Performanee of the fly ash concrete The change of the fly ash to concrete performa nee can be divided into three stages: 1 . Mix con crete stage n ewly: In flue nee the

17、coagulation time of the concrete , is improving and easy , change rheology nature , can improve pump ,etc.;(6) . The con crete stage while harde nning: Regulate the course of harde nning, reduce the heat of hydrati on; 3 . The con crete stage after harde nning: Raise the inten sity on later stage ,

18、raise every durability, such as an ti-permeability, resist the sulphate corrod ing, suppressthe alkali - Collect the material and react etc.3.1 Inten sityThe fly ash has three kinds of in flue nee on the inten sity of con crete: Reduce water con sumpti on , i ncrease glued material content and refle

19、ct through the Ion g-term volca nic ash that raises his intensity. The particle in the fly ash of low calcium is the silicon oxygen tetrahedron structure, one s own activation is very low. In the final result of the cement, high alkali ne water silicic acid calcium and crystallizatio n of 2 colloid

20、of Ca (OH ) are very low in inten sity, especially Ca (OH) 2 ask vigorous to come 1-2% , stone of in te nsity only, but Ca (OH) 2 volume acco unt for whole ceme nt 25% , stone of volume. A large nu mber of silic on , alu minium oxide that contain in the fly ash, can and high alkali ne water silicic

21、acid calcium 2 resp on ses take place with Ca (OH ) 2 progressively, produce inten sity tha n high low alkali ne water silicic acid calcium , so , make cement stone water glue congeal quantity of material in crease, and make its quality improved by a large margin , is favorable to the improveme nt o

22、f the inten sity of con crete. Mean while, to is it can disperse ceme nt particle to mix fly ash, make ceme nt to be ink sufficie nt, improve closely knit degree of the grout , make the inten sity of the in terfaces of the aggregate and grout in the con crete improve. Fly ash is it draw inten sity c

23、ompare with contribution of the bending strength compression strength to be heavy to confront with each other, this is useful to resisti ng the performa nee of splitti ng of con crete.The elastic mould amount of the fly ash con crete is similar to compressi on stre ngth, it is early and on the low s

24、ide, improve progressively later stage , get 28d the con sta nt basic con crete is raised by 5-10%. With to hold strength of wrapping up in reinforcing bar, 28d , fly ash of con crete is it form inten sity the same with ,etc. basic con crete of grade basically to glue, but homoge neity, fly ash of c

25、on crete fin e, is it form inten sity pers on who test gett ing dispersed and kind tha n basic con crete to glue.Water two times of the fly ash reacts and gen erally starts after the con crete builds 14d, whe n temperature is low , will reflect n ecessary time is Ion ger. If strict with early in te

26、nsity of the concrete, the mixing amount of the fly ash is unsuitable to exceed 30%, winter con struct ion large volume at the con crete, the mixi ng amount of the fly ash is un suitable to exceed 20% non-. Because modern concrete China and foreign countries add use of pharmaceutical, on one han d,

27、reducible con crete mix and stir water con sumpti on, it reduce by dust water tha n,of not lasti ng con crete den sity of ceme nt; On the other hand, water-reduc ing age nt can make ceme nt silicic acid calcium ink Ca (OH ) produced 2 in crease, help fly ash and water two times of 2 of Ca (OH ) to r

28、eflect , excites the activati on of the fly ash, this effectual for early intensity to improve fly ash, in addition use fly ash activation excite pharmaceutical or in large volume use stro ng ceme nt early among the con crete non-, can compe nsate mixing the impact on early inten sity of con crete o

29、f fly ash too.3.2 peaceabilityWhether fly ash there are the following several points to concrete and getting easy improveme nt fun cti on.(.The high-quality fly ash contains more tha n 70% of the spherical vitreous bodies, too smooth to have raised an gle the body surface of these spherical glass, p

30、erforma nee is steady, play a kind of lubricated fun cti on which is similar to the beari ng in the pump sending , shak ing the course of smash ing of the con crete .Mix particle apt to gather group ceme nt in the con crete n ewly, to is it can disperse ceme nt particle effectively to mix fly ash, r

31、elease more thick liquid body is it lubricate aggregate to come , help con crete work the improveme nt of performa nee ; (3) .Mix fly ash can compe nsate detailed deficie ncy of bits in the detailed aggregate , cut off mortar base body secrete continuity , water of cha nn el, the fly ash that at the

32、 same time quality is good can reduce the mixi ng water con sumpti on of the con crete un der the same con siste ncy, make water dust of con crete tha n reduce light level to , is it secrete ink and ema nate the phe nomenon to reduce.3.3 shri nkingThe shri nk of the con crete relates to the fact tha

33、t the mixi ng water con sumpti on and thick liquid body body of the con crete are accumulated, the less water con sumpti on is, shri nk the smaller. High-quality fly ash water requirement than smaller than 100% , mix and stir reduct ion , water of qua ntity make mix fly ash con crete after the 28d s

34、ince dry to shri nk and not dry to shri nk little. Fly ash con crete is it is it mix with fly ash improveme nt of qua ntity reduce too to con tract to do. But because water , fly ash of con crete rep onse slowly, moisture evaporate fast, so betwee n fly ash and to do epitome to be loud and very much

35、 heavy in early days con crete. For preve nt early shri nk , fly ash of con crete from fracture , should stre ngthe n in early days rais ing to it3.4 creepsIssue in the past will it be age one day, inten sity of con crete relatively low, issue is it it meets an emerge ncy to be heavy tha n ordi nary

36、 con crete too to creep corresp onding age, but with ordinary concrete fly ash in one age one creep and was smaller than the ordinary con crete after this con crete of inten sity.3.5 carb oni zati on performa neeFly ash concrete resist carbonization to be performanee relatively poor. Cement consumpt

37、ion , fly ash of concrete reduce, cement water Ca (OH ) 2 too corresponding to reduce qua ntity that appear, and volca nic ash is it con sume Ca (OH ) 2 of a certa in amount too to react, make hydroge n ion in dex of the con crete reduce, will in crease the speed of carb oni zati on of the con crete

38、. Uni ess especially at water in early days, fly ash the low in degree in resp onse in volca nic ash,fly ash- there is the loose in structure in hole in system ceme nt, CO2 , O2 , moisture ,etc. i nv ade obstructi on small, so carb oni zati on is relatively large in depth. With the growth of one and

39、 gradual full play of the fly ash volca nic ash effect of age, the speed of carb oni zati on will be reduced gradually. Carboni zatio n , fly ash of con crete as water for dust in depth tha n and fly ash last in crease of qua ntity and not in creased to some exte nt. Than 0.5-0.55 in water dust, fly

40、 ash pers on who mix greater tha n 30% and un der the gen eral con struct ion situati on of compete nee, the depth of carb oni zati on of the con crete can reach about 20mm in 15-17. Carboni zati on reacts and goes on within the range of certa in relative humidity fastest, otherwise, the resp onse i

41、s relatively slow. Un der or is close to 100% 25% in the relative humidity, n amely the occasi on in the abundant dryn ess or water saturati on of con crete, have more difficult to produce carb oni zati on shri nk con cretes. In such con crete projects not con tacted with the atmosphere as the foun

42、dati on works ,etc., because of isolati ng with CO2, can take place carb oni zati on react , so can mix and add the fly ash more , in order to fully reduce the heat of hydrati on of the con crete, improve the durability of the con crete. It is ultra to be adopt law qua ntity replace,water glue n ot

43、lower tha n,mix carry on match ratio desig n water-reduci ng age nt for admixture of main fact at the same time, can make fly ash con crete resist carb oni zati on performa nee improve to some exte nt.3.6 rein forci ng bar corrosi onReinforcing bar of concrete can it antirusts to be becauseconcrete

44、getting alkaline to form one pre-press ing passivati on membra ne in metal surface. Is it add fly ash to mix among con crete, on one hand it con sume Ca (OH ) 2, reduce the alkali en vir onment of the con crete; On the other hand, fly ash 2 resp on ses turn into the hyrate with Ca (OH), raise closel

45、y knit degree of the con crete, in crease the impermeability of the con crete and obstructio n spread to the chlori ne ion, hin der and preve nt the inv asi on of CO2, can shield the reinforcing bar , so fly ash is mixed, in preve nting the reinforcing bar corrosi on, can offset because alkali degre

46、e reduce adverse effect that bring. The fly ash is on certa in range (FA 24% ) of mixi ng amount, have not in flue need the rein forci ng bar corrosi on basically, eve n superior to the bla nk con crete. But if the mixi ng amount of the fly ash is greater tha n 30%, the carb oni zati on of the con c

47、rete can make hydroge n ion in dex of the con crete dropped to about 8.5 from 12.5 , under so low a hydroge n ion in dex con diti on, the reinforcing bar is no Ion ger passivated. Reach reinforcing bar positi on by depth as carb oni zati on, complete carb oni zati on , on terms that water and oxygen

48、 are permeated antiabrasion layer, reinforcing bar can take place but corrosi on lead to the fact fracture of the con crete eve n destroy.3.7 heat of hydrati onThe fly ash is very obvious to reduc ing the fun cti on of the con crete heat of hydratio n. Low calcium fly ash water in the first several

49、days obvious degree have, heat of hydrati on produced only and half of ceme nt. Replace 20% of the ceme nt with fly ash in the con crete , can make the heat of hydrati on of con crete 7d drop by 11% . 1-28d in the issue, roughly for mix perce ntage of fly ash, Sheng Wen and perce ntage that heat of

50、hydrati on reduce age. Fly ash is it can make heat of hydrati on time that peak appear is it appear to 3d to delay gen erally to mix among large volume concrete, can prevent the concrete from producing the temperature crack effectively .粉煤灰高性能混凝土的工程应用摘要本文对粉煤灰高性能混凝土的各项性能作了详细的研究，并针对粉煤灰的掺入量对 混凝土各 种性能的影

51、响以及粉煤灰混凝土在施工中应注意的一些问题进行了分析和探 讨。1概述粉煤灰作为一种工业废料，资源丰富、价格低廉，且含有大量的活性成分，是现代 混凝土中非常重要的一个组分。优质粉煤灰合理地应用于混凝土中，不但能部分代替水 泥，节省工程造价，而且，其特有的性能可以很有效地用于各种使用要求的混凝土中， 改善和提高混凝土的性能，是高性能混凝土中的理想掺和料。在现代混凝土中，粉煤灰 已经与水泥、集料、水、外加剂同样重要，成为混凝土中的一个组分。粉煤灰高性能混 凝土是以耐久性为主要目标进行设计的混凝土。它以优异的耐久性（而不是高强度）为 主要特征，也就是说，任何强度等级的混凝土都可以做成高耐久性混凝土。为

52、达到高耐 久性，粉煤灰混凝土应具备的性能是：在新拌状态有良的工作性，即高流动性而不离析、 不泌水，以使成型均匀、密实，水化硬化早期的沉降收缩和水化收缩小，温升低，硬化 过程干缩小，以达到无初始裂缝，硬化后的渗透性低。2对“粉煤灰效应”的认识粉煤灰的“功能”和“效应”是所有粉煤灰材料技术和工程的应用基础。在混凝土 中掺加粉煤灰，应对粉煤灰的功能作全面的认识，由原来对粉煤灰的“火山灰反应”及 “经济组分”的概念，扩展到“粉煤灰效应”的技术意识，使得粉煤灰功能能够更好地 服务于混凝土的性能改善和质量提高。粉煤灰在混凝土中的作用有以下几点：1 .形态效应：粉煤灰的主要矿物组成是海绵状玻璃体、铝硅酸盐玻

53、璃微珠，这些球形玻璃体表 面光滑，粒度细，质地致密，内比表面积小，对水的吸附力小，这一系列的物理特性， 不仅减小了混凝土的内摩擦阻力，有利于混凝土流动性的提高；而且，对混凝土有不同 程度的“减水”作用；2 .活性效应：粉煤灰的活性成分 SiO2和AI2O3与水泥的水化 产物在有水的情况下发生反应，生成水化硅酸钙（C-S-H）和水化硫铝酸钙（C-A-S-H）, 这些反应几乎都在水泥浆孔隙中进行，生成的水化产物填充、分割原来的大孔，使孔隙细化，可降低混凝土内部的孔隙率，改变孔结构，提高混凝土各组分的粘结作用；3 .微集料效应：粉煤灰中的微细颗粒均匀分布在水泥颗粒之中，填充孔隙，起到“细化孔隙”的作

54、用，同时，阻止水泥颗粒的相互粘聚，而使之处于分散状态，有利于混合 物的水化反应，粉煤灰不会完全与与水泥的水化产物发生反应，能长期保持其“微集料 效应”；4 .界面效应：集料与水泥石之间的界面是混凝土结构中的薄弱环节，过渡区 域的宽度随水灰比、集料吸附特性不同而异，过渡区域具有比水泥浆体更多、更大的孔 隙。掺加粉煤灰能减小过渡区域宽度，干扰过渡区域中Ca(OH 2晶体的取向性，提高混凝土中的界面强度和密实性。3 粉煤灰混凝土的性能粉煤灰对混凝土性能的改变可分为三个阶段： 1 .新拌混凝土阶段：影响混凝土的 凝结时间，改善和易性，改变流变性质，提高可泵性等； 2 .硬化中的混凝土阶段：调 节硬化过

55、程，降低水化热；3 .硬化后的混凝土阶段：提高后期强度，提高各项耐久性， 如抗渗性、抗硫酸盐侵蚀性，抑制碱一集料反应等。3.1强度粉煤灰对混凝土强度有三种影响：减少用水量、增大胶结材含量和通过长期火山灰 反应提高其强度。低钙粉煤灰中的微粒为硅氧四面体结构，自身的活性很低。在水泥的 最终产物中，高碱性水化硅酸钙和 Ca(OH 2胶体的结晶强度很低，特别是 Ca(OH 2 仅是托勃莫来石强度的1-2%,而Ca(OH 2的体积占整个水泥石体积的25%粉煤灰中 含有的大量的硅、铝氧化物，能逐步与 Ca(OH 2及高碱性水化硅酸钙发生二次反应， 生成强度较高的低碱性水化硅酸钙，这样，不但使水泥石中水化胶凝物质的数量增加， 而且也使其质量得到大幅度提高，有利于混凝土强度的提高。同时，粉煤灰的掺入可分 散水泥颗粒，使水泥水化更充分，提高水泥浆的密实度，使混凝土中骨料与水泥浆的界 面强度提高。粉煤灰对抗拉强度和抗弯强度的贡献比抗压强度还要大，这对混凝土的抗 裂性能有利。粉煤灰混凝土的弹性模量与抗压强度相类似，早期偏低，后期逐步提高， 到28d时可比基准混凝土提高5-10%。与钢筋的握裹力，粉煤灰混凝土的 28d粘结强度 基本与等标号的基准混凝土相同，但粉煤灰混凝土的均匀性好，粘结强度试验值的离散 性比基准混凝土好粉煤灰的二次水化反应一般在混凝土浇筑 14d以后