畢業(yè)設計外文翻譯-----bst_500s_鋼筋抗腐蝕性能研究

1、<p>　　本科畢業(yè)設計（論文）翻譯</p><p>　　英文原文名Tensile behavior of corroded </p><p>　　reinforcing steel bars BSt 500s</p><p>　　中文譯名BSt 500s 鋼筋抗腐蝕性能研究</p><p><b>　　班 級<

2、;/b></p><p><b>　　姓 名</b></p><p><b>　　學 號</b></p><p><b>　　指導教師</b></p><p><b>　　填表日期</b></p><p>　　英文

3、原文版出處：EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS</p><p>　　譯文成績： 指導教師簽名： </p><p><b>　　原文：</b></p><p>　　1. Introduction&

4、lt;/p><p>　　Steel bars in reinforced concrete carry mainly tension loads. According to the present day standards, e.g. [1], for involving reinforcing steel in concrete structures, certain minimum values for the

5、 mechanical properties modulus of elasticity (E), yield stress (Rp), ultimate stress (Rm) and elongation to failure (fu) of the steel are required. Furthermore, the standard sets Rm/Rp > 1.05 [1]. </p>

6、<p>　　With increasing service life of a reinforced concrete structure damage accumulates gradually. Nowadays, significant resources are allocated worldwide for the repair and rehabilitation of deteriorating concre

7、te structures. Recent reports indicate that the annual repair costs for the reinforced concrete structures of the network of highways in the USA alone amounts to 20 billion USD [2]. The respective repair costs for reinfo

8、rced concrete bridges in England and Wales amount to 615 million GBP [3].</p><p>　　The underestimation of the corrosion problem arises from the fact that under normal circumstances, concrete provides protect

9、ion to the reinforcing steel. Physical protection of the reinforcing steel against corrosion is provided by the dense and relatively impermeable structure of concrete. The thin oxide layer covering the reinforcement, dur

10、ing concrete hydration, ensures chemical protection. The oxide layer remains stable in the alkaline concrete environment (pH > 13), but begins to deteriorat</p><p>　　The above considerations do

11、not account for the effect of corrosion on the mechanical behavior of the reinforcing steels. Most of the available studies on the corrosion of reinforcing steels refer to the metallurgical aspects of corrosion such as t

12、he mass loss, the depth and the density of pitting etc., e.g. [12] and [13]. It is worth noting that the corroded steel bars are located in a zone of high tensile or shear stresses [5], [12], [14], [15], [16] and [17]. M

13、aslechuddin et al. [10] evaluate</p><p>　　In the present study, the effects of corrosion on the tensile behavior of reinforcing steel bars Class S500s tempcore are investigated. The specimens were pre-corrod

14、ed using laboratory salt spray tests for different exposure times. The dependencies of the degradation of the tensile properties on the corrosion exposure time have been derived. The tensile properties of the corroded ma

15、terial were compared against the requirements set in the standard for involving steels in reinforced concrete struc</p><p>　　2. Experimental research</p><p>　　The experiments were conducted for

16、the steel S500s tempcore, which is similar to the BSt500S steel of DIN 488 part 1 [20]. A stress–strain graph of the uncorroded material is shown in Fig. 1. The chemical composition (maximum allowable % in final product)

17、 of the alloy S500s is: C, 0.24%; P, 0.055%; S, 0.055%; N, 0.013% [21]. </p><p><b>　　(13K) </b></p><p>　　Fig. 1. Stress–strain graph of uncorroded BSt 500s alloy. </p>&l

18、t;p>　　The material was produced by a Greek industry by using the tempcore method (hot rolling followed by quenching and self tempering) and was delivered in the form of ribbed bars. The nominal diameter of the bars wa

19、s 8 mm (Ø8). From the bars, tensile specimens of 230 mm length were cut. The gauge length was 120 mm according to the specification DIN 488 Part 3 [22]. Prior to the tensile tests, the specimens were

20、pre-corroded using accelerated laboratory corrosion tests in salt spray environment. </p><p>　　2.1. Salt spray testing</p><p>　　Salt spray (fog) tests were conducted according to the ASTM B117-9

21、4 specification [23]. For the tests, a special apparatus, model SF 450 made by Cand W. Specialist Equipment Ltd. was used. The salt solution was prepared by dissolving 5 parts by mass of Sodium Chloride (NaCl) into 95 pa

22、rts of distilled water. The pH of the salt spray solution was such that when dissolved at 35 °C, the solution was in the pH range from 6.5 to 7.2. The pH measurements were made at 25 °C. The temperatu

23、re in the zone</p><p>　　2.2. Mechanical testing procedure</p><p>　　The pre-corroded specimens were subjected to tensile tests. All mechanical tests are summarized in Table 1. </p><p&g

24、t;<b>　　Table 1. </b></p><p>　　Tensile tests for S500s Ø8 tempcore steel </p><p>　　The performed tensile tests aim to provide information on: </p><p>　　1. the gradua

25、l deterioration of the mechanical properties of the S500s tempcore steel reinforcement during salt spray corrosion;</p><p>　　2. whether the exposure of the specimens to salt spray might degrade their tensile

26、 property values such that they do no longer meet the limits set by the Hellenic standards for using steel in reinforced concrete structures, e.g. [1] and [24].</p><p>　　The tensile tests were performed acco

27、rding to the DIN 488 specification [22]. For the tests a servo-hydraulic MTS 250 KN machine was used. The deformation rate was 2 mm/min. The tensile properties: yield stress Rp, ultimate stress Rm, elongation to fra

28、cture fu and energy density W0 were evaluated. The energy density is calculated from the area under the true stress–true strain curve. In the present work, the energy density has been evaluated from the engineering stres

29、s–engineering strain curves </p><p>　　as an engineering approximation. </p><p>　　3. Results and discussion</p><p>　　As expected, corrosion damage increases with increasing exposure

30、time to salt spray. The exposure of the specimens to the salt spray environment causes the production of an oxide layer which covers the specimen and increases in thickness with increasing exposure time of the specimen.

31、Removal of the oxide layer by using a bristle brush according to the ASTM G1-90 [25] specification has shown extensive pitting of the specimens already after 10 days of exposure to salt spray. The stereoscopic image</

32、p><p><b>　　(84K) </b></p><p>　　Fig. 2. Stereoscopic images (×35) of (a) uncorroded specimen and (b) specimen exposed to salt spray corrosion for 10 days. </p><p>

33、　　The production of the oxide layer is associated to an appreciable loss of the specimen’s mass. The dependency of the obtained mass loss on the salt spray duration is displayed in Fig. 3. The derived dependency may be f

34、itted by the Weibull function</p><p>　　The determined Weibull values C1 to C4 are given in Table 2. As it can be seen for salt spray duration of 90 days the mass loss of the corroded specimen is about 35% of

35、 the mass of the uncorroded specimen. It is worth noting that the involved salt spray test is an accelerated corrosion test which is performed at the laboratory. Although the salt spray test environment, to some extent,

36、simulates qualitatively the natural corrosion in coastal environment, it is much more aggressive and causes a ve</p><p>　　where a is the measured mass loss in percent and d is the nominal diameter of the unc

37、orroded specimens (8 mm).The reduced values for the nominal specimen diameter are given in Table 3. The reduction specimen diameter with increasing salt spray exposure time is displayed in Fig. 5. The results in Fig

38、. 5 were fitted using Eq. (2). The Weibull values C1 to C4 for Fig. 5 are given in Table 2. </p><p><b>　　(18K) </b></p><p>　　Fig. 3. Effect of the duration of corrosion exposure

39、 on mass loss. </p><p><b>　　Table 2. </b></p><p>　　Weibull values </p><p><b>　　(98K) </b></p><p>　　Fig. 4. Photograph taken from building c

40、onstructed in 1978. </p><p><b>　　Table 3. </b></p><p>　　Values of reduced specimen diameter </p><p><b>　　(18K) </b></p><p>　　Fig. 5. Reduct

41、ion of specimen’s diameter with increasing duration of corrosion exposure. </p><p>　　It is essential to notice that the strength calculation of steel reinforced concrete structures according to the standards

42、, e.g. [24], occurs by using an engineering stress estimated by assuming the cross-sectional area as</p><p>　　with d being the nominal diameter of the bars. For the bars of the present study, the nominal dia

43、meter was 8 mm. According to the valid standards, there is no special consideration for the reduction of the nominal diameter of the reinforcing steel, even when evaluating the strength of an older reinforced concre

44、te structure indicating a severe corrosion damage of the reinforcing bars as shown in Fig. 4. Displayed in Fig. 6 and Fig. 7 are the apparent values of the engineering yield stress and ult</p><p>　　where G i

45、s the weight and l is the length of the specimen, whereas for the apparent strength values, the cross-sectional area was calculated by using Eq. (4). The dependencies of the effective engineering yield and ultimate stres

46、s on the duration of salt spray exposure are displayed in Fig. 6 and Fig. 7 as well. As it can be seen in the figures, the corrosion attack causes a moderate tensile strength reduction which increases with increasing dur

47、ation of the corrosion exposure, even though for th</p><p><b>　　and</b></p><p>　　The constants A1, B1, B2, A2, B3 and B4 in Eqs. (6) and (7) were derived to 596.19291, ?2.59222, 0.00

48、563, 695.67537, ?2.92755 and 0.01375, respectively. </p><p><b>　　(23K) </b></p><p>　　Fig. 6. Effect of the duration of corrosion exposure on yield strength. </p><p>

49、;<b>　　(23K) </b></p><p>　　Fig. 7. Effect of the duration of corrosion exposure on ultimate stress. </p><p><b>　　Table 4. </b></p><p>　　Mechanical proper

50、ty degradation during salt spray corrosion </p><p>　　Even though the actual effect of corrosion on the tensile engineering strength properties of the reinforcing steel is moderate, the corrosion damage probl

51、em for the integrity of an older reinforced concrete structure remains significant. It is noticeable that the effective engineering strength of the corroded specimens Rmeff drops below the limit set by the standards as t

52、he minimum requirement for the stress value at about 40 days salt spray corrosion exposure. As it is shown in Fig. 8, it repre</p><p>　　with σ0 being the applied stress for the uncorroded material. For the c

53、ase under consideration, it refers to a bar with d0 = 8 mm. An example of the increase on applied stress as a result of the reduction of the load carrying cross-section with increasing duration of the salt

54、 spray exposure is shown in Fig. 8. The values taken for σ0 for the two curves in Fig. 8 were 280 and 320 MPa, respectively. The synergistic effect of the observed decrease on the effective strength values of the ma

55、terial an</p><p><b>　　(22K) </b></p><p>　　Fig. 8. Applied stress increase as a function of the duration of corrosion exposure. </p><p>　　The effects of increasing c

56、orrosion damage on the tensile ductility of the investigated steel bars are shown in Fig. 9 and Fig. 10. Both elongation to fracture, Fig. 9, and energy density, Fig. 10, decrease appreciably with increasing duration of

57、the salt spray exposure. The value of elongation to fracture meets the requirement fu  12%, as requested by the standards in [1], for exposures to salt spray of up to 35 days. As discussed above, the corrosion

58、damage referring to 35 days laboratory salt</p><p><b>　　(19K) </b></p><p>　　Fig. 9. Effect of the duration of corrosion exposure on elongation to fracture. </p><p>

59、<b>　　(16K) </b></p><p>　　Fig. 10. Effect of the duration of corrosion exposure on energy density. </p><p>　　The standards do not require for the evaluation of the energy density

60、 W of the reinforcing steel. Energy density is a material property which characterizes the damage tolerance potential of a material and may be used to evaluate the material fracture under both, static and fatigue loading

61、 conditions [26]. Note that energy density may be directly related to the plain strain fracture toughness value, KIC, e.g. [27], which evaluates the fracture of a cracked member under plain strain loading condit</p>

62、;<p>　　The observed appreciable reduction on tensile ductility may represent a serious problem for the safety of constructions in seismically active areas. As during the seismic erection, the reinforcement is ofte

63、n subjected to stress events at the region of low cycle fatigue, the need for a sufficient storage capacity of the material is imperative. </p><p>　　4. Conclusions</p><p>　　? The exposure of the

64、 steel bars S500s tempcore to salt spray environment results to an appreciable mass loss which increases with increasing duration of exposure. Durations of laboratory salt spray exposures of 40 days or longer are realist

65、ic for simulating natural corrosion damage obtained at members of old buildings at coastal sites.</p><p>　　? The effect of salt spray exposure on the strength properties of the steel S500s is moderate. Yet,

66、with regard to the observed appreciable mass loss, the increase on the effective engineering stress is essential such as to spend the reserves on strength which are required in the standards trough safety factors.</p&

67、gt;<p>　　? The effect of salt spray exposure on the tensile ductility of the material is appreciable. For salt spray exposures longer than 35 days, elongation to fracture drops to values lying below the fu =&

68、#160;12% limit which is required in the standards.</p><p>　　? Present day standards for calculating strength of reinforced concrete members do not account for the appreciable property degradation of the rein

69、forcing steel bars due to the gradually accumulating corrosion damage. Although, a revision of the standards such as to account for the above corrosion effects on the material properties seems to be required, further ext

70、ensive investigation is needed to conclude on proper recommendations for such a revision.</p><p>　　References</p><p>　　[1] Hellenic Regulation for the Technology of Steel in Reinforced Concrete;

71、 no. Δ14/36010-29.2/24.3.2000 (Government Gazette Issue) 381B. </p><p>　　[2] Strategic High Research Program. Concrete and Structures; Progress and Product Update. Washington, DC: National Research Council;

72、1989. </p><p>　　[3] E.J. Wallbank, The performance of concrete in bridges, HMSO, London (1989). </p><p>　　[4] D.G. Manning, Design life of concrete highway structures – The North American scene,

73、 Design Life Struct (1992), pp. 144–153. </p><p>　　[5] J.P. Broomfield, Corrosion of steel in concrete, E & FN Spon, London (1997) p. 22. </p><p>　　[6] Papadakis VG. Supplementary cementing

74、materials in concrete – activity, durability and planning. Danish Technological Institute Concrete Center, January; 1999. </p><p>　　[7] Roberto Capozucca, Damage to reinforcement concrete due to reinforcemen

75、t corrosion, Construct Build Mater 9 (1995) (5), pp. 295–303.</p><p>　　[8] S.E. Diamond, Chloride concentrations in concrete pore solutions resulting from calcium and sodium chloride admixtures, Cement Concr

76、ete Aggr 8 (1986) (2), pp. 97–102. </p><p>　　[9] M.G. Alvarez and J.R. Galvele, The mechanisms of pitting of high purity iron in Nacl solutions, Corros Sci 24 (1984), pp. 27–48. </p><p>　　[10] M

77、. Maslehuddin, I.M. Ibrahim, Huseyin Saricimen and Abdulaziz l. Al-Mana, Influence of atmospheric corrosion on the mechanical properties of reinforcing steel, Construct Build Mater 8 (1993) (1), pp. 35–41. </p>&l

78、t;p>　　[11] Congqi Fang, Karin Lundgren, Liuguo Chen and Chaoying Zhu, Corrosion influence on bond in reinforced concrete, Cement Concrete Res (2004). </p><p>　　[12] Borgard B, Warren C, Somayaji S, Heider

79、sbach R. Mechanisms of corrosion of steel in concrete. ASTM STP 1065, Philadelphia; 1990. p. 174. </p><p>　　[13] M.D.A. Thomas and J.D. Mathews, Performance of pfa concrete in a marine environment – 10-year

80、results, Cement Concrete Compos 26 (2004), pp. 5–20. </p><p>　　[14] T. Yonezawa, V. Ashworth and R.P.M. Procter, Pore solution composition and chloride effects on the corrosion of steel in concrete, Corrosio

81、n 44 (1988), pp. 489–499. </p><p>　　[15] M.F. Montemor, A.M.P. Simoes and M.M. Salta, Effect of fly ash on concrete reinforcement corrosion studied by EIS, Cement Concrete Compos 22 (2000), pp. 175–185. <

82、/p><p>　　[16] B. Elsener, Macrocell corrosion of steel in concrete – implications for corrosion monitoring, Cement Concrete Compos 24 (2002), pp. 65–72. </p><p>　　[17] C. Arya and P.R.W. Vassie, In

83、fluence of cathode-to-anode area ratio separation distance on galvanic corrosion currents of steel in concrete containing chlorides, Cement Concrete Res 25 (1995), pp. 989–998. </p><p>　　[18] A.A. Almusallam

84、, Effect of degree of corrosion on the properties of reinforcing steel bars, Construct Build Mater 15 (2001) (8), pp. 361–368. </p><p>　　[19] Mpatis G, Rakanta E, Tsampras L, Mouyiakos S, Agnantiari G. Corro

85、sion of steel used in concrete reinforcement, in various corrosive environments, Technical Chamber of Greece, 13th Hellenic Convention for Concrete. vol. II, Rethymnon, Crete; 1999. p. 497–505. </p><p>　　[20

86、] DIN 488-1, Reinforcing steel grades, properties, marking; 1986. </p><p>　　[21] ELOT 971, Hellenic standard, weldable steels for the reinforcement of concrete, 1994-04-01. </p><p>　　[22] DIN 48

87、8-3, Reinforcing steel bars testing; 1986. </p><p>　　[23] ASTM B 117-94, Standard practice for operating salt (fog) testing apparatus. In: Annual book of ASTM standards, section 3, Metal test methods and ana

88、lytical procedures, West Conshohocken, ASTM, Philadelphia, USA; 1995. p. 1–8. </p><p>　　[24] Hellenic Anti-Seismic Code 2000 (EAK 2000). </p><p>　　[25] ASTM G1 – 90, Standard practice for prepar

89、ing, cleaning, and evaluating corrosion test specimens. </p><p>　　[26] G.C. Sih and C.K. Chao, Failure initiation in unnotched specimens subjected to monotonic and loading, Theor Appl Fract Mech 2 (1984), pp

90、. 67–73. </p><p>　　[27] D.Y. Jeong, O. Orringen and G.C. Sih, Strain energy density approach to stable crack extension under net section yielding of aircraft fuselage, Theor Appl Fract Mech 22 (1995), pp. 12

91、7–137. </p><p><b>　　譯文：</b></p><p>　　BSt 500s 鋼筋抗腐蝕性能研究</p><p><b>　　1. 前言</b></p><p>　　在鋼筋混凝土中鋼筋主要承受拉力. 根據(jù)今天的標準,例如 [1]、對涉及鋼筋混凝土結構、最小彈性模量(E)、屈服強度

92、(Rp),極限壓力(Rm)和鋼筋的塑性(fu)等是必要的. 此外,這個標準規(guī)定Rm/Rp > 1.05 [1].</p><p>　　在日益鋼筋水泥結構的壽命逐漸累積損失. 目前,全世界的重要資源分配修復混凝土結構惡化. 最近的報告顯示,每年的維修費鋼筋混凝土結構的公路網(wǎng),僅相當于美國的20億美元[2]. 有關鋼筋混凝土橋梁維修費英格蘭和威爾士6.15億英鎊等于[3]. 然而,盡管近年來實際問題殘余力量鋼筋

93、混凝土結構老化退化,引起相當大的注意,但還遠沒有充分了解,更不用說解決. 值得注意的是,到現(xiàn)在為止,沒有進行過工作,占侵蝕影響的機械性能加固鋼筋,所以就退化的承載能力的鋼筋混凝土部分[4]. 這些都影響了有效降低截面的鋼筋、混凝土的微觀和宏觀裂縫和最后的水泥剝落.</p><p>　　被低估的腐蝕問題的出現(xiàn),是因為在正常情況下,具體規(guī)定了保護鋼筋. 對人身保護的鋼筋腐蝕提供了較為稠密,不透水的混凝土結構. 薄的氧

94、化層復蓋加固,在具體水化、化學防護保障. 在保持穩(wěn)定的堿性氧化物層的具體環(huán)境(酸堿度"13),而開始惡化時的孔隙榮獲解決少于11 [5] 和 [6].</p><p>　　由于故障率低于酸堿腐蝕時上漲9. 開始的腐蝕,氧化或depassivated電影必須打破. 如果堿度depassivation可能發(fā)生的孔隙減少毛細孔的具體辦法和/或氯離子滲透的發(fā)生. 這可能是造成碳化,特別是在靠近裂縫,伴隨水稀釋的

95、作用產(chǎn)生裂縫[7], [8]和[9]. 進一步腐蝕造成的削減負荷截面酒吧和增加其數(shù)量,這可能造成的裂痕,以及具體明顯下降的債券之間的實力和鋼筋混凝土[10]和 [11].</p><p>　　上述因素的影響,還不是在腐蝕鋼筋鋼機械行為. 現(xiàn)有的大部分研究腐蝕鋼指加強冶金等方面的腐蝕重量損失、深度和密度等對立,例如[12] 和 [13]. 值得指出的是,鋼筋腐蝕區(qū)位于高張力、剪壓[5], [12], [14], [

96、15], [16] 和 [17]. AlMaslechuddin網(wǎng)站. 10影響評價的大氣腐蝕鋼筋機械性能. 他們不是結束,為期16個月,受大氣腐蝕、銹蝕所產(chǎn)生的影響是微不足道的,最終鋼筋的抗拉強度. Almusallam18度影響評估的鋼筋混凝土腐蝕、重量損失%表示,他們的機械特性. 研究結果表明兩者之間的關系非常密切,沒有特色,磚、鋼筋腐蝕鋼筋. 突然失敗磚flexure在觀察時表示腐蝕程度增加重量損失超過13%左右. 上述成果的鞏

97、固腐蝕鋼機械行為是指自家人打自家人的420s牛488(s420s根據(jù)希臘的標準). 以上結果清楚地表明,必須占侵蝕影響的機械特性的鋼筋牛500s(s500s根據(jù)希臘的標準),目前幾乎全部采用鋼筋混凝土結構. 值得注意的是,腐蝕破壞的鋼筋,今后將更加明顯,新的建筑用鋼筋s500s,因為這種鋼展品體積更大損失侵蝕而鋼班和S400S2201</p><p>　　在本次研究的張力行為的影響腐蝕鋼筋強化班S500sTemp

98、core調(diào)查. 物種是前鹽腐蝕噴射實驗室用不同曝光時間進行測試. 退化的附庸張力財產(chǎn)所得的曝光時間腐蝕. 張力腐蝕材料性能的要求,而對標準涉及的鋼筋混凝土結構鋼.</p><p><b>　　2. 實驗研究</b></p><p>　　他的實驗進行鋼TempcoreS500s,類似于Bst500s鋼的一部分148820自家人打自家人. 一緊張壓力的圖表顯示模型unco

99、rroded材料. 1. 化學成份(最大可成最終產(chǎn)品)的合金s500s是: C, 0.24%; P, 0.055%; S, 0.055%; N, 0.013% [21]. </p><p>　　圖1. BSt 500s 新合金壓力曲線</p><p>　　物質是由希臘工業(yè)用Tempcore方法(冷、熱軋自我鍛煉之后),是以網(wǎng)吧玩. 名義上是直徑8毫米酒吧(ø8). 從酒吧、張力標

100、本230毫米長度削減. 長度是120毫米的各種規(guī)格按4883部分Din22. 張力測試之前,樣本是前使用加速腐蝕試驗的腐蝕鹽噴實驗環(huán)境. </p><p>　　210. 鹽噴射測試 鹽米(霧)據(jù)測試,ASTMB117-9423規(guī)格. 為測試、特殊儀器、450名模范奧委會提出cand設備有限公司是專門用于W. 鹽水的解散是由5部分群眾的氯化鈉(NACL)95個地區(qū)為蒸餾水. <宋慶齡的解決辦法是用這種鹽

101、,當在350C解散,由宋慶齡在解決6.5to7.2. 測量水的比重均在25C. 高溫區(qū)加固材料暴露在鹽米保持在350C廳+1.1-1.7℃C. 當暴露結束后,樣品是自來水沖洗干凈,以消除其表面的鹽礦床,然后被干. 此外,一些同樣長的鋼筋受到鹽的使用1、2、4天監(jiān)測腐蝕損壞演變.</p><p>　　22. 機械測試程序 </p><p>　　前張力遭到腐蝕試驗樣品. 所有機械試驗見表1

102、. </p><p><b>　　表1. </b></p><p>　　張力測試S500sØ8Tempcore鋼</p><p>　　張力的表演測試旨在提供資料: 1. 逐漸惡化的機械性能TempcoreS500s在鹽噴霧腐蝕鋼加固; 2. 是否接觸到的標本用食鹽可降低這種財產(chǎn)價值的張力,他們不再滿足設定的標準,希臘的