土木工程畢業(yè)設(shè)計外文翻譯2篇

1、<p><b>　　畢業(yè)設(shè)計（論文）</b></p><p><b>　　外文翻譯</b></p><p>　　設(shè)計（論文）題目： </p><p>　　學(xué) 院 名 稱： 建筑工程

2、 </p><p>　　專 業(yè)： 土木工程 </p><p>　　學(xué) 生 姓 名： 學(xué)號： </p><p>　　指 導(dǎo) 教 師： <

3、;/p><p>　　2010年01月10日</p><p><b>　　外文原文I：</b></p><p>　　A fundamental explanation of the behaviour of</p><p>　　reinforced concrete beams in flexure based</p&g

4、t;<p>　　on the properties of concrete under multiaxial stress</p><p>　　M. D. Kotsovos</p><p>　　Department of Civil Engineering, Imperial College of Science and Technology, London (U. K.)&

5、lt;/p><p>　　The paper questions the validity of the generally accepted view that for a reinforced concretestructure to exhibit "ductile" behaviour under increasing load it is necessary for the stresss

6、train relationships of concrete to have a gradually descending post-ultimate branch.Experimental data are presented for reinforced concrete beams in bending which indicate the presence of longitudinal compressive strains

7、 on the compressive face in excess of 0.0035. It is shown that these strains, which are esse</p><p>　　1. INTRODUCTION</p><p>　　The "plane sections" theory not, only is generally consid

8、ered to describe realistically the deformation response of reinforced and prestressed concrete beams under flexure and axial load, but is also formulated so that it provides a design tool noted for both its effectiveness

9、 and simplicity [1]. The theory describes analytically the relationship between load-carrying capacity and geometric characteristics of a beam by considering the equilibrium conditions at critical cross-sections. Compati

10、bil</p><p>　　The stress-strain characteristics of concrete in compression are considered to be adequately described by the deformational response of concrete specimens such as prisms or cylinders under uniax

11、ial compression and the stress distribution in the compression zone of a cross-section at the ultimate limit state, as proposed by current codes of practice such as CP 110 [1], exhibits a shape similar to that shown in f

12、igure 1. The figure indicates that the longitudinal stress increases with the</p><p>　　distance from the neutral axis up to a maximum value and then remains constant. Such a shape of stress distribution has

13、been arrived at on the basis of both safety considerations and the widely held view that the stress-strain relationship of concrete in compression consists of both an ascending and a gradually descending portion (seefig.

14、 2). The portion beyond ultimate defines the post-ultimate stress capacity of the material which, Typical stress-strain relationship for concrete in compression</p><p>　　However, a recent analytical investig

15、ation of the behaviour of concrete under concentrations of load has indicated that the post-ultimate strength deformational response of concrete under compressive states of stress has no apparent effect on the overall be

16、haviour of the structural forms investigated ( [2], [3]). If such behaviour is typical for any structure, then the large compressive</p><p>　　strains (in excess of 0.0035) measured on the top surface of a re

17、inforced concrete beam at its ultimate limit state (see fig. 1), cannot be attributed to post-ultimate uniaxial stress-strain characteristics. Furthermore, since the compressive strain at the ultimate strength level of a

18、ny concrete under uniaxial compression is of the order of 0.002 (see fig. 2), it would appear that a realistic prediction of the beam response under load cannot be based solely on the ascending portion of the uniaxi</

19、p><p>　　In view of the above, the work described in the following appraises the widely held view that a uniaxial stress-strain relationship consisting of an ascending and a gradually descending portion is essen

20、tial for the realistic description of the behaviour of a reinforced concrete beam in flexure. Results obtained from beams subjected to flexure under two-point loading indicate that the large strains exhibited by concrete

21、 in the compression zone of the beams are due to a triaxial state of stress ra</p><p>　　2. EXPERIMENTAL DETAILS</p><p>　　2.1. Specimens</p><p>　　Three rectangular reinforced concret

22、e beams of 915 mm span and 102 mm height x 51 mm width cross-section were subjected to two-point load with shear spans of 305 mm (see fig. 3). The tension reinforcement consisted of two 6 mm diameter bars with a yield lo

23、ad of 11.8 kN. The bars were bent back at the ends of the beams so as to provide compression reinforcement along the whole length of the shear spans.Compression and tension reinforcement along each shear span were linked

24、 by seven 3.2 mm diamete</p><p>　　The beams, together with control specimens, were cured under damp hessian at 20~ for seven days and then stored in the laboratory atmosphere (20~and 40% R.H.) for about 2 mo

25、nths, until tested. Full details of the concrete mix used are given in table I.</p><p>　　2.2. Testing</p><p>　　Load was applied through a hydraulic ram and spreader beam in increments of approxi

26、mately 0.5 kN. At each increment the load was maintained constant for approximately 2 minutes in order to measure the load and the deformation response of the specimens. Load was measured by using a load cell and deforma

27、tion response by using both 20 mm long electrical resistance strain gauges and displacement transducers. The strain gauges were placed on the top and side surfaces of the</p><p>　　beams in the longitud{nal a

28、nd the transverse directions as shown in figure 4. The figure also indicates the position of the linear voltage displacement transducers (LVDT's) which were used to measure deflexion at mid-span and at the loaded cro

29、ss-sections.</p><p>　　The measurements were recorded by an automatic computer-based data-logger (Solatron) capable of measuring strains and displacements to a sensitivity of 2 microstrain and 0.002 ram, re

30、spectively. </p><p>　　3. EXPERIMENTAL RESULTS</p><p>　　The main results obtained from the experiments together with information essential for a better understanding of beam behaviour are shown i

31、n figures 5 to 14. Figure 5 shows the uniaxial compression stressstrain relationships of the concrete used in the investigation, whereas figures 6 and 7 show the relationships between longitudinal and transverse strains,

32、 measured on the top surface of the beams (a) at the cross-sections where the flexure cracks which eventually cause failure are situated (cri</p><p>　　Figures 6 and 7 also include the longitudinal straintran

33、sverse strain relationship corresponding to the stress-strain relationships of figure 5.</p><p>　　Figure 8 shows the typical change in shape of the transverse deformation profile of the top surface of the be

34、ams with load increasing to failure and figure 9 provides a schematic representation of the radial forces and stresses developing with increasing load due to the deflected shape of the beams. Typical load-deflexion relat

35、ionships of the beams are shown in figure 10, whereas figure 11 depicts the variation on critical sections of the average vertical strains measured on the side surfaces of</p><p><b>　　中文翻譯I：</b>&

36、lt;/p><p>　　在多向應(yīng)力作用下從混凝土的特性看受彎鋼筋混凝土梁</p><p><b>　　變化的一個基本試驗</b></p><p>　　M. D. Kotsovos 倫敦皇家科學(xué)與技術(shù)學(xué)院土木工程系</p><p>　　本文所探討的問題是通常認為在荷載遞增下鋼筋混凝土結(jié)構(gòu)呈現(xiàn)彈性狀態(tài)，這必須是因為混凝土的應(yīng)力

37、-應(yīng)變關(guān)系有一個逐漸遞減的臨界部分的真實性。試驗數(shù)據(jù)顯示受彎鋼筋混凝土梁會在受壓面的縱向壓應(yīng)變超出0.0035。這表明這些應(yīng)變是鋼筋混凝土結(jié)構(gòu)的本質(zhì)，它是由于一個比極限強度小的復(fù)雜多向的應(yīng)力狀態(tài)而不是塑性材料的特性引起的。一個復(fù)雜應(yīng)力系統(tǒng)的存在為梁的狀態(tài)提供了一個基本試驗，而不是想象的一個現(xiàn)有設(shè)計過程。</p><p><b>　　1.引言</b></p><p>　

38、　“剖面”理論不僅是通常認為能很真實地描述鋼筋混凝土梁和預(yù)應(yīng)力混凝土梁在彎矩和軸向荷載下的變形，而且能確切地闡述，所以它提供了一個設(shè)計工具，因為它的有效和簡單而聞名[1]。假設(shè)在臨界橫截面?zhèn)蔷獾?，這個理論分析地描述了一個梁的承載能力和幾何特性之間的關(guān)系。變形協(xié)調(diào)必須滿足“水平橫截面荏苒水平”的假定和縱向混凝土和鋼筋的應(yīng)力是通過材料的應(yīng)力-應(yīng)變的特性來估算的。為了簡化計算，忽略橫向的應(yīng)力和應(yīng)變。</p><p>

39、;　　受壓混凝土的應(yīng)力-應(yīng)變特性認為能夠被混凝土試塊的變形充分地描述，例如在極限的有限狀態(tài)下，棱柱體或圓柱體在橫截面的受壓區(qū)受單軸壓力和應(yīng)力，就像現(xiàn)行規(guī)范所建議的CP110[1]，顯示出一個與圖1相似的形狀。圖1表明縱向應(yīng)力隨著與中和軸的距離增加而增加至最大值，然后保持不變。這個分布圖已經(jīng)達到安全性和受壓混凝土的應(yīng)力-應(yīng)變關(guān)系的廣泛觀點，由上升和逐漸下降的兩部分組成(如圖2所示)。超出極限的部分，材料的塑性應(yīng)力能力如圖1所示，被認為對梁

40、的最大承載能力有較大的作用。</p><p>　　圖1.臨界面破壞建議CP為110的應(yīng)力和應(yīng)變分布 圖2.受壓混凝土結(jié)構(gòu)的標(biāo)準應(yīng)力-應(yīng)變關(guān)系</p><p>　　然而，最近關(guān)于在集中力作用下的混凝土的變化的一個分析性調(diào)查表明，在壓應(yīng)力作用下混凝土的極限強度變形沒有對所有被調(diào)查的結(jié)果形式的變化產(chǎn)生明顯的影響([2],[3])。如果這個變化對任何結(jié)果都是典型的，那么在鋼筋混凝土梁的

41、頂面被測的很大的壓應(yīng)變(超出量0.0035)在它的極限有限狀態(tài)下(如圖1)，不能對極限單軸應(yīng)力-應(yīng)變特性產(chǎn)生作用。因此，因為壓應(yīng)變在單軸壓力下的任何混凝土的極限強度等級下為ε=0.002(如圖2所示)，在混凝土的單軸應(yīng)力-應(yīng)變關(guān)系下降部分，將出現(xiàn)一個在荷載作用下梁變化的現(xiàn)在可行的預(yù)測。</p><p>　　根據(jù)以上的觀點，本文的描述都在以下的評價中，廣泛的支持觀點的一個單軸應(yīng)力-應(yīng)變關(guān)系由一個上升的和一個逐漸下降

42、的部分組成，對受彎的根據(jù)混凝土梁的變化的真實描述是非常必要的。這個結(jié)果是從梁在兩點荷載作用下彎曲得到，表明很大的應(yīng)變的通過梁受壓的混凝土呈現(xiàn)的，由于三維應(yīng)力而不是一味的混凝土極限應(yīng)力-應(yīng)變特性。這表明材料本身受到一個完整和直接的承載能力損失，當(dāng)極限強度被超過的假定與彈性結(jié)構(gòu)的變化并存的，通過偏心荷載或瞬間旋轉(zhuǎn)關(guān)系表明的。</p><p><b>　　2.試驗細節(jié)</b></p>

43、<p><b>　　2.1試塊</b></p><p>　　三根矩形鋼筋混凝土梁，跨度915mm，橫截面為102mm51mm，受剪區(qū)跨度為305mm(如圖2所示)。受力筋由兩個直徑為6mm，屈服荷載為11.8kN的鋼筋組成。在梁端部鋼筋彎起，就能為整個受剪跨度提供抗力。整個受剪跨度內(nèi)壓縮張拉的加強筋布置了七個直徑為3.2mm的箍筋。在梁的中間部分沒有壓縮加強筋和箍筋。根據(jù)上面所述

44、的鋼筋布置，所有的梁都是受彎破壞而不是受剪破壞，盡管剪跨比為3。</p><p>　　所有的梁與受控的試塊一起放在20 的濕麻袋下七天，然后貯存在實驗室條件下(20,40%濕度)2個月，直到試驗結(jié)束。所有混凝土配料都在表格I中。</p><p><b>　　2.2試驗過程</b></p><p>　　通過液壓錘和分布梁加載，每次大約增加0.5k

45、N。為了測量荷載和試塊的形變，每次持荷約2分鐘。荷載用一個荷載單元來測量，形變由20mm長的電阻應(yīng)變片和位移轉(zhuǎn)換器測得。應(yīng)變片貼在梁縱向和橫向的頂面和側(cè)面(如圖4所示)。圖4也表明了直流電壓位移轉(zhuǎn)換器（LVDT’S）的位置，它是用來測量跨中和加載橫截面的形變。</p><p>　　測量數(shù)據(jù)記錄在計算機自動數(shù)據(jù)記錄儀中，能夠測量應(yīng)變和形變的靈敏度分別為±2微應(yīng)變和±0.002mm。</p&

46、gt;<p><b>　　3.試驗結(jié)果</b></p><p>　　主要的試驗結(jié)果是從試驗中得到的，能更好地了解梁的變化，所示圖5 至圖14的信息是必不可少的。圖5表明結(jié)果的單軸壓應(yīng)力-應(yīng)變關(guān)系應(yīng)用于調(diào)查中，而圖6 和圖7表明縱向應(yīng)變與橫向應(yīng)變的關(guān)系，分別位于(a)彎曲裂縫最終導(dǎo)致破壞橫截面出和(b)受剪區(qū)跨內(nèi)的橫截面出。圖6和圖7也包含了縱向應(yīng)變-橫向應(yīng)變與圖5的應(yīng)力-應(yīng)變關(guān)

47、系是一致的。</p><p>　　圖8中標(biāo)準的改變在梁頂面的橫向形變輪廓圖中和圖9提供一個軸力和應(yīng)力隨著荷載的增加而增大，導(dǎo)致梁向下變形的圖框表示方法。梁的標(biāo)準偏心荷載關(guān)系如圖10所示，而圖11描述了測得平均豎向應(yīng)變的梁側(cè)面的臨界截面變形和橫向應(yīng)變在頂面測得。圖12中標(biāo)準結(jié)果的強度和形變在各種狀態(tài)的十三軸應(yīng)力下河圖13所呈現(xiàn)的梁標(biāo)準裂縫圖樣在破壞的瞬間。最后圖14表明在臨界截面的受壓區(qū)傷縱向應(yīng)力的分布形狀，可根據(jù)

48、概念來預(yù)測破壞，在以下部分將被討論。</p><p><b>　　圖3.梁的細節(jié)</b></p><p><b>　　外文原文II:</b></p><p>　　Some questions on the corrosion of steel in concrete.</p><p>　　Part

49、Ⅱ: Corrosion mechanism and monitoring, service</p><p>　　life prediction and protection methods</p><p>　　J.A. Gonzdlez , S. Felifd, P. Rodffguez , W. Lfpez , E. Ramlrez , C. Alonso , C. </p>

50、;<p><b>　　Andrade </b></p><p><b>　　ABSTRACT</b></p><p>　　This second part addresses some important issues that remain controversial despite the vast amounts of wor

51、k devoted to investigating corrosion in concrete-embedded steel. Specifically,these refer to: 1) the relative significance of galvanic macrocouples and corrosion microcells in reinforced concrete structures; 2) the mecha

52、nism by which reinforcements corrode in an active state; 3) the best protective methods for preventing or stopping reinforcement corrosion; 4) the possibility of a reliable p</p><p>　　1. INTRODUCTION</p&g

53、t;<p>　　Concrete-embedded steel is known to remain in apassive state under normal conditions as a result of the highly alkaline pH of concrete. The passivity of reinforcements ensures unlimited durability of reinf

54、orced concrete (1KC) structures. However, there are some exceptional conditions that disrupt steel passivity and cause reinforcements to be corroded in an active state. This has raised controversial interpretations, some

55、 of which were discussed in Part I of this series [1]. This Part II analyse</p><p>　　2. MATERIALS AND METHODS</p><p>　　The reader is referred to Part I for a detailed description of the material

56、s and methods used in this work. Most of the experimental results discussed herein were obtained with the same types of specimens and slabs.Galvanic couples were determined on speciallydesigned specimens, such as those s

57、hown in Figs. 1 and 2.Near-real conditions were simulated by using a beam that was 160cm long and 7 x 10 cm in cross-section. The beam was made from 350 kg cement/m 3, half of which</p><p>　　contained no add

58、itives, while the other half included 3% CaC12 by cement weight [2], (Fig. 1). In order to study the effect of the Sanod/Scathoa ratio on galvanic macrocouples, they were modelled by surrounding a small carbon steel anod

59、e with a stainless steel (AISI 304) cathode and vice versa</p><p>　　(Fig. 2). In this way, the ratio's consistensy was assured. In addition, the potential and icorr of stainless steal and those of the pa

60、ssive structures were very similar.</p><p>　　Fig. 1 - Beam used to measure icoTr and Ecorr in Fig. 2 - Scheme of galvanic macrocouples embedded</p><p>　　concrete with and without chlorides a

61、nd to in chloride- containing mortar used to study the</p><p>　　illustrate the significance of passive steel/active effect of the Sanod/Scathod ratio and their relative</p><p>　　s

62、teel macrocouples. significance to corrosion microcells.</p><p>　　3. RESULTS AND DISCUSSION</p><p>　　3.1 What is the relative significance of galvanic macrocouples a

63、nd corrosion</p><p>　　microcells in RC structures ?</p><p>　　According to several authors [3, 5], the polarization resistance method provides an effective means for estimating the corrosion rate

64、 of steel in P,C ; the method is quite rapid, convenient, non-destructive, quantitative and reasonably precise. However, it is uncertain whether it may give rise to serious errors with highly-polarized electrodes by the

65、effect of passive/active area galvanic</p><p>　　macrocouples in the reinforcements [6].</p><p>　　Based on the authors' own experience with the behaviour of galvanic macrocouples in PC, the c

66、ontribution of these macrocouples to overall corrosion is very modest rehtive to that of the corrosion microcells formed in the active areas of reinforcements in the presence of sufficient oxygen and moisture [2, 7, 8].

67、Thus, it has been experimentally checked that:</p><p>　　(a) Galvanic macrocouples have a slight polarizing effect on anodic areas in wet concrete, whose potential is thereby influenced in only a few millivol

68、ts.</p><p>　　(b) On the other hand, macrocouples have a strong polarizing effect on passive areas despite the low galvanic currents involved relative to the overall corrosion current.</p><p>　　(

69、c) As a result, galvanic currents can result in grossly underestimated icorr values for the active areas since they are often smaller than 10% of the ico= values estimated from polarization resistance measurements.</p

70、><p>　　(d) The corrosive effect ofcoplanar macrocouples on RC structures only proves dangerous within a small distance from the boundary of active and passive areas.</p><p>　　Fig. 3 compares the es

71、timated icorr and ig values, in mortar containing 3 o~ A CaC12, per anode surface unit for a number of anode/cathode surface ratios for AISI 304 stainless steel/carbon steel macrocouples in support of the above conclusio

72、ns [9].</p><p>　　3.2 By what mechanism do reinforcements corrode in an active state ?</p><p>　　When the passive state is lost, the rate of reinforcement corrosion in inversely proportional to th

73、e resistivity of concrete over a wide resistivity range [10]. Because </p><p>　　Fig. 3 - Relative significance of corrosion microcells Fig. 4 - Trends in ico. and Ecorr for</p><p>　　(icor

74、r) and galvanic macrocouples (i.) in corrosion specimens exposed to an oxygen-free </p><p>　　of steel embedded in mortar containing no chloride. environment.</p><p>　　Both currents wer

75、e calculated relative to Sanod</p><p>　　(carbon steel in the macrocouples of Fig. 2).</p><p>　　the environment's relative humidity and ionic additives of concrete determine concrete resistiv

76、ity, these factors, together with oxygen availability at reinforcement surfaces,control the corrosion rate [11].</p><p>　　The electric resistivity of water-saturated concrete structures is relatively very lo

77、w, and the corrosion rate is believed to be essentially controlled by the diffusion of dissolved oxygen through the concrete cover up to reinforcements. This is consistent with the widespread belief that the sole possibl

78、e cathodic reaction in neutral and alkaline solutions is oxygen reduction.</p><p>　　The significance ascribed to the role of oxygen justifies the efforts to determine its diffusion coefficient in concrete[12

79、, 13]. The variety of methods and experimental conditions used for this purpose have led to a wide range of diffusivity values (from 10 -12 to 10 -8 m2/s) for oxygen in</p><p>　　cement paste [14].</p>

80、<p>　　Since the diffusion coefficient of oxygen in aqueous solutions (1)O2 = 10 -5 cm2/s-1), is saturation concentration (CO2 = 2.1 x 10 -7 mol/cm 3) and the approximate thickness of diffusion layers in stagnant so

81、lutions (8 = 0.01 cm) are wellknown, the limiting diffusion current can be calculated as :</p><p>　　ilo2 = - z FD02C02/r = 8 x 10 -4 A/cm 2 (80 pA/cm 2)</p><p>　　where z is the number of equival

82、ents per mole (4) and F the Faraday (96,500 A.s/eq).</p><p>　　For 1-cm thick mortar covers of average porosity 15%(see Fig. 1 in Part I) [1] and a diffusioja layer thickness of the same order as the cover th

83、ickness, 11o2 = 0.12 laA/cm 2, which is quite consistent with the icorr values estimated under pore saturation conditions at the end of the curing</p><p>　　process, both for mortars containing no chloride io

84、ns and for those including 2, 4 or 6% C1- [16].</p><p>　　On the other hand, icorr values of ca. 10 liA/cm 2 (see Fig. 9 in Part I) [4] have been obtained by several authors for mortars with chlorides or carb

85、onated mortars which are incompatible with the rates allowed by the limiting diffusion current of oxygen. Therefore, in some circumstances, alternative cathodic processes allowing for faster kinetics must therefore be in

86、volved. In recent work, the concurrence of crevices, chloride ions and dissolved oxygen at the steel/concrete interface was claime</p><p>　　There are a number of facts that refute oxygen reduction as being t

87、he sole corrosion rate-determining step, namely: </p><p>　　- Under some circumstances, once corrosion in an active</p><p>　　state has started, it develops at the same rate even though oxygen is

88、being removed from the medium (Fig. 4) [11].</p><p>　　- As saturation of concrete pores decrease, concrete resistivity controls ico~r over a wide resistivity range ; therefore, the corrosion rate seems to de

89、crease in proportion to the ease with which oxygen penetrates into the structure(Fig. 5)[10].</p><p>　　On the other hand, there are several arguments in favour of proton reduction in Ca(OH)2-saturated soluti

90、ons or cement mortars [11] :</p><p>　　- The pH decreases from 12.6 to ca. 5 within crevices at the steel/electrolyte interface upon exposure of the steel to a Ca(OH)2-saturated solution with C1- additions an

91、d wellaerated. If sufficient oxygen is available, the pH can drop as low as 1-2.</p><p>　　- The emergence of acid exudates ofpH 1-5 from cracks and macropores in chloride-containing mortar specimens under we

92、t atmospheres at high corrosion rates (5-10 pA/cm2).</p><p>　　- The formation of gas bubbles over iron hydroxide membrane-coated pits when the steal is polarized anodically in a Ca(OH)2-saturated, chloride-c

93、ontaminated solution at potentials below those required for oxygen release. Everything points to pits with a low enough pH for the anodic current applied to overlap with a corrosion process involving proton reduction as

94、a cathodic half-reaction.</p><p>　　When concrete-embedded steel is corroded in an active state, its corrosion kinetics rise exponentially with increasing pore saturation (Fig. 6), similarly to atmospheric co

95、rrosion in bare steel as the environment's relative humidity increases [18]. At some points in the reinfor- cements, a catalytic cycle may take place, e.g., those put forward by Schikorr for atmospheric corrosion of

96、steel [19], with chloride ion rather than SO2-as the catalyst (Fig. 6).</p><p>　　Fig. 5 - Relationship between mortar resistivity Fig. 6 - Influence of the degree of pore saturation</p><p>　

97、　and the corrosion rate of reinforcements. on the corrosion rate of reinforcements.</p><p><b>　　中文翻譯II:</b></p><p>　　混凝土中鋼腐蝕的有關(guān)問題</p><p>　　Ⅱ：腐蝕機理和監(jiān)督、使用年限的預(yù)測和保護方法

98、</p><p>　　J.A. Gonzdlez , S. Felifd, P. Rodffguez , W. Lfpez , E. Ramlrez , C. Alonso , C. </p><p><b>　　Andrade </b></p><p>　　摘要:第二部分闡述幾個仍然存在爭議的重要問題，盡管已經(jīng)在混凝土中鋼腐蝕的調(diào)查研究投入了

99、大量的工作。特別是這幾方面：1)在鋼筋混凝土結(jié)構(gòu)中的大電偶和腐蝕微電池對的相對重要性；2)激活狀態(tài)的鋼筋腐蝕機理；3)阻止或停止鋼筋腐蝕最好的保護方法；4)一個鋼筋混凝土結(jié)構(gòu)使用年限的可靠預(yù)測的可能性探索；5)最好的防腐措施和控制方法。這些回答需要試驗得出，大部分都由作者們得出。</p><p><b>　　1.前言</b></p><p>　　正常條件下強堿混凝土中

100、的鋼仍然處于鈍化狀態(tài)。鋼筋的鈍性能保證鋼筋混凝土結(jié)構(gòu)無限的耐久性。然而，有一些能破壞鋼的鈍性和引起鋼筋腐蝕的實驗條件。在第Ⅰ部分中討論到的一些實驗結(jié)構(gòu)已經(jīng)引起了很多爭論[1]。第Ⅱ部分的分析雖然沒有竭盡全力，但至少是作者的意思，就像有趣的問題有不同的意見一樣。</p><p><b>　　2.材料和方法</b></p><p>　　讀者指出在第Ⅰ部分詳細描述了用于這項

101、工作的材料和方法。這里所討論的大部分實驗結(jié)果都是從一樣的試塊和平板中得到的。電偶是由特殊設(shè)計的試塊確定的，如圖1和2所示。用一根長16m，70mm×100 mm橫截面的梁模擬近真實條件。梁是由每立方米350kg水泥制成，梁的一半含有添加劑，另一半含有水泥的重量的3%的CaCl2[2]，(圖1)。為了了解S正極/S負極的比值對大電偶的影響，用在一個小的碳素鋼正極環(huán)繞一個不銹鋼負極并夾緊來模擬。這樣，比值的連貫性是可靠的。此外，與