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1、本科畢業(yè)設(shè)計(論文)外文翻譯譯文學(xué)生姓名: 院 (系): 專業(yè)班級: 指導(dǎo)教師: 完成日期: 年 月 日 要 求1、外文翻譯是畢業(yè)設(shè)計(論文)的主要內(nèi)容之一,必須學(xué)生獨立完成。2、外文翻譯譯文內(nèi)容應(yīng)與學(xué)生的專業(yè)或畢業(yè)設(shè)計(論文)內(nèi)容相關(guān),不得少于15000印刷符號。3.外文翻譯譯文用a4紙打印。文章標(biāo)題用3號宋體,章節(jié)標(biāo)題用4號宋體,正文用小4號宋體,20磅行距;頁邊距上、下、左、右均為2.5cm,左側(cè)裝訂,裝訂線0.5cm。按中文翻譯在上,外文原文在下的順序裝訂。4、年月日等的填寫,用阿拉伯?dāng)?shù)字書寫,要符合關(guān)于出版物上數(shù)字用法的試行規(guī)定,如“2005年2月26日”。5、所有簽名必須手寫,不得
2、打印。文獻(xiàn)名稱在混凝土的修復(fù)過程中的腐蝕抑制劑和其他保護(hù)系統(tǒng):真正的理解或者誤解文獻(xiàn)名稱corrosion inhibitors and other protective systems in concrete repair: concepts or misconcepts作者:r.dhanaraj起止頁碼:168-172出版日期(期刊號):isbn 7-5608-2492-7出版單位:dept. of civil engg. crescent engg. college, india.外文翻譯譯文:在混凝土的修復(fù)過程中的腐蝕抑制劑和其他保護(hù)系統(tǒng): 真正的理解或者誤解在最近的一段時間內(nèi),在世界
3、的很多地方,早期鋼筋的腐蝕而對混凝土結(jié)構(gòu)產(chǎn)生的早期惡化和損壞,已經(jīng)成為混凝土結(jié)構(gòu)方面的主要問題。加速這個惡化過程的一個主要因素是混凝土結(jié)構(gòu)所存在的環(huán)境和氣候狀況。惡劣的環(huán)境與低質(zhì)量的混凝土加上有或無缺陷的設(shè)計和建設(shè)慣例,這都使結(jié)構(gòu)惡化的過程變得具有交互性,累積得非常迅速,進(jìn)而形成一種惡性的發(fā)展,而且很難被停止。很多混凝土結(jié)構(gòu)耐久性差的性能正引起結(jié)構(gòu)產(chǎn)生裂縫.而在補(bǔ)救工作的支出,則使物主和社會所不能承擔(dān),并且他們也不希望看到悲劇重演。這篇文章僅提出一些對鋼筋腐蝕和保護(hù)選擇的初步認(rèn)識,而對混凝土和混凝土修理的抑制混合物腐蝕的影響則進(jìn)行了詳細(xì)討論。與抑制劑在修理效力有關(guān)的復(fù)雜論文已經(jīng)發(fā)表,其中主要對
4、基于電化學(xué)活動在新結(jié)構(gòu)和修復(fù)結(jié)構(gòu)方面之間差別進(jìn)行了分析。隨著盲目的對需要修理的混凝土使用那些適用于新建筑的保護(hù)方法,文章斷定:修復(fù)混凝土的生意將會越來越好。一種對新的和需要修理的混凝土之間的電化學(xué)差別的更廣泛理解認(rèn)為對修理的結(jié)構(gòu)使用有效的鋼筋保護(hù)是必要的。1.序言這是一個不幸的事實。全世界范圍內(nèi),大量混凝土結(jié)構(gòu)都處在惡化/ 危險狀態(tài)的階段。同時,必須承認(rèn)的是,很多被修理的混凝土結(jié)構(gòu)在幾年后,一修再修。被修理混凝土結(jié)構(gòu)的保持性能的長久表現(xiàn)則最大限度的取決于它們的設(shè)計,建設(shè),維護(hù)和使用。與建筑在修理的幾年之后出現(xiàn)裂縫相比,幾乎沒有問題能加劇公眾與政府之間的沖突,并且導(dǎo)致他們對我們提供的建筑物用途的
5、功能感到不滿意。然而與預(yù)期相反,不管是惡劣的環(huán)境狀況還是適合的環(huán)境狀態(tài),在混凝土修理過程中,腐蝕的問題已經(jīng)變得非常普遍.因而,混凝土修理業(yè)正面臨一項主要的挑戰(zhàn): 怎樣制止全世界物質(zhì)基礎(chǔ)設(shè)施的腐壞。它是如此重要,對當(dāng)今的混凝土修復(fù),我們要迫切檢查腐蝕和腐蝕保護(hù)措施的發(fā)行,且探索在不久的將來它有可能改進(jìn)的地方, 即:如何使現(xiàn)在的修理能耐用到將來。一種用于修理結(jié)構(gòu)的,對導(dǎo)致過早腐蝕過程的基本理解仍然沒有涉及混凝土的修理單元。而它不僅應(yīng)用于修復(fù)結(jié)構(gòu)鋼筋銹蝕的過程和混凝土的惡化腐蝕過程, 而且也被應(yīng)用于多種被提議的溶液腐蝕保護(hù)技術(shù),材料和系統(tǒng)。他們應(yīng)用實際的歷史非常悠久,但它們在許多案例中的表現(xiàn)是可疑的
6、。在混凝土修復(fù)過程中的鋼筋腐蝕和保護(hù)的范圍內(nèi),這篇文章提出了一些隨機(jī)想法。本文圍繞修理過程中鋼的腐蝕的基本過程,闡明了與電化學(xué)性質(zhì)相反的原理,講述了這些過程怎樣導(dǎo)致合成修理系統(tǒng)的最后失敗的道理。為了延長混凝土結(jié)構(gòu)的使用壽命,文章也敘述了我們能或者不能成功解決這幾個問題的方法。終究,我們必須從繁忙的工作表中周期性地抽身出來,回顧一下,我們在哪里和我們可能將要去哪里。當(dāng)然,在這篇文章里,有一些想法可能會引起其它人同意或者不同意的意見。但是只有當(dāng)想法得到爭論時,才可能取得進(jìn)步,并且這也是本篇文章的目的。在這里提供關(guān)于腐蝕和保護(hù)問題各方面的重要評論是不可能的.那些問題相對于本篇中的某個的重要討論來說太
7、廣泛,而且各種各樣的結(jié)構(gòu)過于復(fù)雜。關(guān)于混凝土中鋼筋腐蝕和保護(hù)的一般問題,許多作者已經(jīng)詳細(xì)闡述過,在這里就不再敖述了。研究已經(jīng)實質(zhì)上改進(jìn)了我們對水泥材料的認(rèn)識, 碳酸飽和引起腐蝕式的混凝土消耗,氯化物引起腐蝕的理論:硫酸鹽侵蝕,堿類聚合反應(yīng),嚴(yán)寒等等。但是,由于在混凝土的修補(bǔ)過程中鋼筋的嚴(yán)重腐蝕和惡劣自然環(huán)境中的修復(fù)和修復(fù)失敗,使得修補(bǔ)工業(yè)發(fā)展的如此緩慢,這或許可歸因于下列綜合因素:混凝土修補(bǔ)是一種非常復(fù)雜的系統(tǒng)。它要暴露在外部環(huán)境和內(nèi)部的環(huán)境,并受到環(huán)境間的相互作用。目前,提出腐蝕問題的基本原理指導(dǎo)還未發(fā)表。在復(fù)雜的修理環(huán)境中,鈍化的裝置和鋼鐵的腐蝕不被人了解。整個區(qū)域中,現(xiàn)在關(guān)于修理中鋼筋的
8、附加保護(hù)問題得到了大家的廣泛關(guān)注。預(yù)埋入水泥中的鋼筋的腐蝕是種極其復(fù)雜的現(xiàn)象,這種現(xiàn)象的形成涉及到環(huán)境學(xué),冶金學(xué),分界面和連續(xù)統(tǒng)一體等因素。此領(lǐng)域中的大多數(shù)學(xué)術(shù)研究,對于工人來說沒有足夠?qū)I(yè)知識來處理,已經(jīng)由國家工程高校組織力量集中解決。得到支持的行業(yè)和政府代表展現(xiàn)了對于解決問題的決心。真正的過程不是以學(xué)者在倉促時間內(nèi)的工作做為基礎(chǔ)。項目的啟動,必須需要科學(xué)的可執(zhí)行計劃和充足的資金做為基礎(chǔ)。一個烏托邦夢想存在,是因為問題可能被藉由使用高性能的材料,防腐劑,保護(hù)材料等等或者安全帶和懸掛系統(tǒng)等措施來解決。這使得在工地上許多工人忽略了混凝土技術(shù)的基本要素和其他基本水泥材料。要設(shè)計耐用修理的知識在馬瑟
9、 1的著作完全精煉說明里已經(jīng)敘述, 但是這種使用此知識的方式是第一次。一些在修理領(lǐng)域內(nèi)的研究已經(jīng)涉及到修理材料和他們與現(xiàn)有實體有關(guān)的空間行為特性的改進(jìn)。但是只要電化學(xué)的兼容性的問題也考慮解決,這些活動將產(chǎn)生在修理耐久性方面的改進(jìn)。惡化混凝土的去除和它的修理材料的替代品,即使與最好的一種一起替換,也可能由于宏單元的形成而加速鋼筋腐蝕。這篇文章的主題致力于解決若干令人困惑的議題,并且試圖從混凝土修理過程中的過早腐蝕問題建立關(guān)于鋼筋保護(hù)的事實,特別是提出關(guān)于防腐材料的問題。我們怎樣能期望被修理的混凝土結(jié)構(gòu)是耐用的呢?如果測驗方法,腐蝕保護(hù)方法的設(shè)計和說明都不可靠,難道依賴在修理系統(tǒng)里的電化學(xué)類似于那
10、在新建筑里發(fā)生的不適當(dāng)?shù)募俣▎??修理工作和新建筑有著重要的不同,不同因素?jīng)常導(dǎo)致新的修理混凝土結(jié)構(gòu)方面的鋼筋腐蝕。因此,在保護(hù)方法上有所體現(xiàn)。為修理結(jié)構(gòu)中鋼筋的附加保護(hù),而批評已存在的方法和材料,或者徹底討論一個保護(hù)系統(tǒng)的優(yōu)點或者過失不是本論文的意圖。作者沒有表達(dá)明確意見,或者至少對修理結(jié)構(gòu)的保護(hù)鋼筋的正確或錯誤方法表示合理客觀的意見。非常抱歉的是,并不如此。問題太復(fù)雜,因為現(xiàn)有的知識不能夠提供一劑萬能方法來解決現(xiàn)有的問題。由于鋼筋鋼過早的腐蝕而產(chǎn)生修理失敗的結(jié)果和可能性,不一定是一種單個的過分簡化的解決辦法,這可能適合于新近建造的結(jié)構(gòu)。在修理領(lǐng)域內(nèi),我們的成功可能取決于我們解決爭論的能力。把
11、感覺和廢話區(qū)別開。無論我們做什么,無用的言論總是很多。在這個領(lǐng)域,由于缺乏適當(dāng)?shù)慕逃壳霸S多專業(yè)詞語被錯誤定義。不適當(dāng)?shù)慕逃脱芯吭谌魏晤I(lǐng)域都將要花大力氣來改正誤解。作者意識到當(dāng)一些論點成為爭論的關(guān)鍵時,那些論點將很難讓人達(dá)成共識。而且這種情況,遠(yuǎn)遠(yuǎn)多過一根頭發(fā)?;蛟S,我們將從誤解中來剝離真正的理解。2.腐蝕問題:(1)用于被修理混凝土結(jié)構(gòu)嵌入鋼筋的腐蝕和它的保護(hù)是一個非常復(fù)雜的現(xiàn)象。 很多修理失敗可能歸因于缺乏對自然和電化學(xué)活動在修理系統(tǒng)內(nèi)結(jié)果的完整理解。因此,預(yù)言一個保護(hù)系統(tǒng)的性能和一棟修理結(jié)構(gòu)的使用年限是不太準(zhǔn)確的。 (2) 在聲稱多種特性的市場上有許多腐蝕保護(hù)處理方法。他們保護(hù)鋼筋防
12、止腐蝕的行為沒有處理好,并且沒有可靠的標(biāo)準(zhǔn)測驗方法評價他們所表現(xiàn)的性能。 適量的研究要求為不同系統(tǒng)的評估作準(zhǔn)備。需要知道結(jié)構(gòu)負(fù)擔(dān)這種保護(hù)有多久,修理結(jié)構(gòu)的保護(hù)就有多好。為了給技術(shù)人員建立自信,科學(xué)家應(yīng)該為預(yù)知措施和預(yù)測的壽命提供可信的基點。 (3) 過度期望或者修理系統(tǒng)的糟糕表現(xiàn)以及暴露狀況,特別在實驗室中的內(nèi)部測試,經(jīng)常產(chǎn)生使人誤解的結(jié)果。如果過去評價這些保護(hù)系統(tǒng)的測驗方法,既不反映出修理結(jié)構(gòu)中腐蝕的機(jī)制,也不刺激在一個真正修理的結(jié)構(gòu)里而導(dǎo)致鋼筋腐蝕的物理化學(xué)效應(yīng)。我們怎能期望花費(fèi)在修理的鋼筋附加保護(hù)上錢沒被浪費(fèi)?目前使用過的一些測驗方法以后的研究范圍也相當(dāng)狹窄。 (4) 各種不同的保護(hù)方法
13、的調(diào)查員都在說他們方法的效力總是比在高質(zhì)量混凝土中還好??梢詳喽ǜ哔|(zhì)量新混凝土和高質(zhì)量的修理是埋入鋼筋防止腐蝕的最好保護(hù)系統(tǒng) - 這是混凝土技術(shù)的基礎(chǔ)。 保護(hù)措施可以另外采取,但不是做為使用基礎(chǔ)的正確代用品。 (5) 這篇文章的中心主題考慮的不是作者在幾個問題上意見的正確或者錯誤; 那是不相關(guān)的。它的意思是提出的問題不是無法解釋的秘密,只是我們?nèi)匀辉谔剿骼锏囊粋€證明,簡稱研究階段。畢竟本杰明富蘭克林說過,做永遠(yuǎn)比說好!abstractin recent times in many parts of the world, reinforcement corrosion has become th
14、e main factor in early, premature deterioration, and sometimes failure, of concrete structures. one of the major factors contributing to this deterioration process is the environmental and climatic conditions to which a concrete structure is exposed. when the severity of environment is compounded wi
15、th poor quality concrete and/or defective design and construction practices, the process of deterioration becomes interactive, cumulative and very rapid, and a cancerous growth that cannot be easily stopped. the poor durability performance of many concrete structures is causing disruption and expend
16、iture on remedial works which owners and society cannot afford and do not wish to see repeated. a glimpse of reinforcement corrosion and some of the protection options is presented in this paper. the effect of corrosion inhibiting admixtures in concrete and concrete repair is discussed in detail. th
17、e complex issue related to the effectiveness of inhibitors in repairs is addressed, based on analysis of the differences between electrochemical activities in new and repaired structures. the paper concludes that as long as one continues to blindly use protection methods applicable for newly constru
18、cted structures for concrete repairs, the business of repairing the repairs will be on the rise. a broader understanding of the electrochemical differences between new and repaired concrete is necessary for effective protection of reinforcement in repaired structures.2003 elsevier ltd. all rights re
19、served.keywords: alkalinity; corrosion protection; durability; inhibitors; reinforcement1. introductionit is an unfortunate fact that very large amounts of existing concrete structures worldwide are in a state of eterioration/distress. at the same time, it must also be recognized that many repaired
20、concrete structures are severely deteriorated only a few years after being repaired. the performance of repaired concrete structures remains a matter of utmost concern to all those involved with their design, construction, maintenance and use. few problems aggravate the public and lead to their diss
21、atisfaction with our ability to provide for the structures use than the disruption of its use a few years after repairs. contrary to the expectations, the problem of corrosion in concrete repairs has become widespread not only with respect to severe environmental conditions but also with respect to
22、moderate environmental condition.the concrete repair industry is thus facing a major challenge: how to halt the decay of the worlds physical infrastructure. it is therefore important that we critically examine the issue of corrosion and corrosion protection in todays concrete repair and explore how
23、it can be improved in the near future, i.e.: how to make todays repairs durable for tomorrow. a basic understanding of the processes leading to premature corrosion in repaired structures still eludes the concrete repair community. this applies not only to the processes of corrosion of reinforcement
24、in repaired structures and deterioration/ distress of concrete, but also to a variety of the proposed solutionscorrosion protection techniques, materials and systems. they have a highly empirical history of use, and their performance in many cases is questionable.this paper offers some random though
25、ts in the area of reinforcement corrosion and protection in concrete repair. it encompasses the elucidation of the basic processes of corrosion of steel in repair, electrochemical incompatibility, and how these processes may lead to eventual failure of the composite repair system. the paper is also
26、about how we can, or cannot, successfully address these problems with the aim of prolonging lifetime of existing concrete structures. after all, we must pause periodically from our busy schedules to review where we are and where we might be going. of course, there are some thoughts in this paper whi
27、ch may lead others to agree or disagree. but it is only when ideas receive a forum that progress can be made, and that is the goal of this paper.it is not possible here to provide a critical review of numerous aspects of corrosion and corrosion protection, the problems are too extensive and various
28、mechanisms too complicated for a critical discussion in a single paper. general aspects of steel corrosion in concrete and its protection have been treated by a number of authors and will not be addressed here.research has substantially improved our knowledge of cementitious materials, the fundament
29、als of concrete deterioration from carbonation-induced corrosion, chloride-induced corrosion, sulphate attack, alkaliaggregate reaction, frost, etc. however, in view of the serious and insidious nature of the corrosion of steel in concrete repair and repair failures, it is surprising that progress i
30、n the repair industry has been so slow, which is probably attributable to some combination of the following: the exterior and interior environments and their interaction. problems does not exist. the mechanism of passivation and corrosion of steel in a complex repair environment is poorly understood
31、. the whole area concerning “additional protection” of reinforcement in repair is currently highly speculative. is an extremely complex phenomenon involving environmental, metallurgical, interfacial, and continuum considerations. most of the research in this area is being done by the civil engineeri
32、ng departments of universities where few workers have adequate knowledge of the subject. in support of research leading to a resolution to problems. real progress cannot be made on the basis of graduate students working for limited periods. it is necessary to initiate programs which include a balanc
33、ed practical approach and are adequately funded. by using high performance materials, corrosion inhibitors, protective coatings, etc., or belt and suspender systems. this caused many workers in the field to ignore the basics in the technology of concrete and other cement-based materials.ficant knowl
34、edge to design durable repairs already exists in a relatively “quite refined state”, as stated by mather 1. but the manner in which this knowledge is used is primitive.several research studies in the repair field have been concerned with the improvement of properties of repair materials and their di
35、mensional behaviour relative to the existing substrate. but these activities will lead to improvements in repair durability only if the issues of electrochemical compatibility are also addressed. removal of deteriorated concrete and its replacement with a repair material, even the best one, may resu
36、lt in accelerated rebar corrosion due to macrocell formation.the subject of this paper is also devoted to several confusing issues and attempts to establish the facts concerning the protection of reinforcement from premature corrosion in concrete repair, particularly that offered by corrosion inhibi
37、tors.how can we expect repaired concrete structures to be durable if the testing methods, design and specification of corrosion protection methods, are relying on an inadequate assumption that electrochemistry in a repair system is similar to that occurring in new construction? there are significant
38、 differences between new construction and repair jobs; there are often different factors leading to corrosion of reinforcement in new an repaired concrete structures and, therefore, in the methods of protection.it is not the intent of this paper to criticize existing methods and materials for additi
39、onal protection of reinforcement in repairs, or to discuss in depth the merits or demerits of one protection system against another. the author can offer no panacea, or at least express a reasonably objective view of the right and wrong way to protect reinforcement in repaired structures. much to ou
40、r regret, this is not so. the problem is too complex because the existing knowledge is not sufficient to offer a panacea.the consequence and probability of repair failure due to the premature corrosion of the reinforcing steel is not necessarily a single simplistic solution as may be appropriate for
41、 newly constructed structures. our success in the repair field may depend on our ability to resolve the controversies, to differentiate sense from nonsense. the nonsense will be abundant, no matter what we do: this field, due to the lack of proper education, is presently well positioned to import a
42、lot of misconceptions; any field where education and research are inadequate is going to have great trouble getting rid of the prevailing misconceptions.the author realizes that some statements will not be shared by many since it hits at the crux of the controversy. but in this case, much more than
43、a hair, perhaps, divides concepts from misconcepts.2. a glimpse of corrosion problemaccording to published data, steel reinforcement in concrete and in concrete-like materials is, in general, well protected from corrosion by the alkaline nature of the cementitious matrix surrounding it. in general,
44、this is true, it is protected, and it is not supposed to corrode. but such concrete in general may only exist as labcrete, in a small specimen. in the real world, reinforcing and prestressing steels are subject to corrosion due to carbonation and chloride ion attack.steel reinforcement in concrete d
45、oes not corrode because the surface of the steel in the alkaline environment is passivated; steel in concrete corrodes when its surface is depassivated during the manufacturing of the structure, or becomes active during service. corrosion is the electrochemical reaction, and the important factor aff
46、ecting a corrosion cell is the difference in potentials of the metal. the driving force for current and corrosion is the potential development. since the structure of steel and the contact layer of concrete are both heterogenous, the requirement for potential difference between the separate portions
47、 of the metal surface (the electrochemical inhomogeneity) is always satisfied.concrete is a permeable material, where aggressive agents diffuse (micropermeability) through it and reach the reinforcing steel, causing its depassivation and corrosion, when water and oxygen are available. corrosion by t
48、his mode however, is a relatively lengthy process. concrete is a brittle material and always contains microcracks. when these microcracks combine in a network with macrocracks, the prevailing transport mechanism is not diffusion, it is the permeation of water and aggressive agents via water through
49、the cracks to the reinforcement (macropermeability). why enter through the closed door, when an open door is nearby?high permeability of concrete and other cementbased materials affected by cracking is truly responsible for the lack of durability. for corrosion to occur, it is necessary that both th
50、e passivating .lm on the steel is destroyed and that there exists a differential electrochemical potential within the steelconcrete system.the natural protection of steel by the high alkalinity of cement matrix is disturbed due to the following reasons: chemical reaction between the products of hydr
51、ation of cement and carbon dioxide which diffuses from the atmosphere (carbonation). carbonation by diffusion is a very lengthy process: approximately 1 mm of concrete cover carbonates in a year. cracks in the concrete, on the other hand, allow carbon dioxide easy permeation through the concrete cov
52、er, and carbonation occurs rapidly. level. chloride ions may penetrate into the concrete due to one of three processes: diffusion due to a concentration gradient, absorption from salt solutions form, and/or by flow of the solution through the cracks.the differential electrochemical potential may dev
53、elop due to the dissimilarities in the chemical environment of steel, such as the result of nonuniformed carbonation, the variation in the rate of penetration of chlorides, moisture, oxygen, etc. reinforcing steel in the variety of a crack starts to corrode from a localized depassivation of steel be
54、cause of the weakened steel-cement-matrix contact and disturbed steel passivating film. steel depassivates from reduced alkalinity at the surface of the reinforcement, or from accumulation of aggressive ions, chlorides, in particular.acid gasses and aggressive ions penetrate the cracked material muc
55、h easier than they do in crack-free concrete. the active coefficient of carbon dioxide diffusion (penetration) in a concrete crack 0.20 mm (0.008 in.) wide is about three orders of magnitude higher than in average quality crack-free concrete. the same holds true for the transport of aggressive ions,
56、 the rate of substance transfer by capillary suction is even greater. according to previous data reinforcement in a crack wider than 0.1 mm (0.004 in.) initially corrodes more rapidly than the unprotected steel, both in the air and with the cyclic wetting and drying 2. a high initial rate of steel c
57、orrosion in the cracked concrete versus the unprotected steel, apart from the effect of microcells, can be accounted for by a much longer preservation of moisture on the steel surface in the crack than on the open steel surface. chlorides also penetrate faster through cracks towards the reinforcemen
58、t. cracks often have a high chloride concentration at the root of the crack near the reinforcing steel. as soon as corrosion starts, the rate of corrosion is controlled by the conductivity of the concrete, the difference in potential or voltage between the anodic and cathodic areas, and the rate atwhich oxygen reaches the cathode. the width and the direction of cracks are not of critical importance, but the amount of cracks per unit of area is critical.repairs are more prone to cracking
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