【正文】 現(xiàn)有的大部分研究腐蝕鋼指加強(qiáng)冶金等方面的腐蝕重量損失、深度和密度等對(duì)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], [15], [16] 和 [17]. AlMaslechuddin 網(wǎng)站 . 10 影響評(píng)價(jià)的大氣腐蝕鋼筋機(jī)械性能 . 他們不是結(jié)束 ,為期 16 個(gè)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(qiáng)度 . Almusallam18 度影響評(píng)估的鋼筋混凝土腐蝕、重量損失 %表示 ,他們的機(jī)械特性 . 研究結(jié)果表明兩者之間的關(guān)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(shí)表示腐蝕程度增加重量損失超過 13%左右 . 上述成果的鞏固腐蝕鋼機(jī)械行為是指自家人打自家人的 420s牛 488(s420s 根據(jù)希臘的標(biāo)準(zhǔn) ). 以上結(jié)果清楚地表明 ,必須占侵蝕影響的機(jī)械特性的鋼筋牛 500s(s500s 根據(jù)希臘的標(biāo)準(zhǔn) ),目前幾乎全部采用鋼筋混凝土結(jié)構(gòu) . 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?yàn)檫@種鋼展品體積更大損失侵蝕而鋼班和 S400S22020. 記得許多鋼筋混凝土建筑物位于沿海地區(qū)有強(qiáng)烈腐蝕性的環(huán)境 . 另一方面 ,腐蝕了廣泛使用抗鋼筋不應(yīng)指望這些酒吧約需六至九倍多平原碳鋼筋 . 在本次研究的張力行為的影響腐蝕鋼筋強(qiáng)化班 S500sTempcore 調(diào)查 . 物種是前鹽腐蝕噴射實(shí)驗(yàn)室用不同曝光時(shí)間進(jìn)行測試 . 退化的附庸張力財(cái)產(chǎn)所得的曝光時(shí)間腐蝕 . 張力 腐蝕材料性能的要求 ,而對(duì)標(biāo)準(zhǔn)涉及的鋼筋混凝土結(jié)構(gòu)鋼 . 2. 實(shí)驗(yàn)研究 他的實(shí)驗(yàn)進(jìn)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 uncorroded材料 . 1. 化學(xué)成份 (最大可成最終產(chǎn)品 )的合金 s500s是 : C, %。8). 從酒吧、張力標(biāo)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(yàn)的腐蝕鹽噴實(shí)驗(yàn)環(huán)境 . 210. 鹽噴射測試 鹽米 (霧 )據(jù)測試 ,ASTMB1179423 規(guī) 格 . 為測試、特殊儀器、 450 名模范奧委會(huì)提出 cand 設(shè)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(gè)地區(qū)為蒸餾水 . 宋慶齡的解決辦法是用這種鹽 ,當(dāng)在 350C解散 ,由宋慶齡在解決 . 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 +℃C. 當(dāng)暴露結(jié)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 4 天監(jiān)測腐蝕損壞演變 . 22. 機(jī)械測試程序 前張力遭到腐蝕試驗(yàn)樣品 . 所 有機(jī)械試驗(yàn)見表 1. 表 1. 張力測試 S500s216。 S, %。 1986. [21] ELOT 971, Hellenic standard, weldable steels for the reinforcement of concrete, 19940401. [22] DIN 4883, Reinforcing steel bars testing。 FN Spon, London (1997) p. 22. [6] Papadakis VG. Supplementary cementing materials in concrete – activity, durability and planning. Danish Technological Institute Concrete Center, January。 2. whether the exposure of the specimens to salt spray might degrade their tensile property values such that they do no longer meet the limits set by the Hellenic standards for using steel in reinforced concrete structures, . [1] and [24]. The tensile tests were performed according to the DIN 488 specification [22]. For the tests a servohydraulic MTS 250 KN machine was used. The deformation rate was 2 mm/min. The tensile properties: yield stress Rp, ultimate stress Rm, elongation to fracture 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 stress–engineering strain curves as (1) as an engineering approximation. 3. Results and discussion As expected, corrosion damage increases with increasing exposure 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. Removal of the oxide layer by using a bristle brush according to the ASTM G190 [25] specification has shown extensive pitting of the specimens already after 10 days of exposure to salt spray. The stereoscopic image of a specimen after exposure to salt spray for 10 days is shown in Fig. 2. It is pared against the image of the uncorroded material. It was observed that the corrosion attack started at the rib roots and advanced towards the area between the ribs. The indentations of the corrosion attack left on the specimen surface after removal of the oxide layer increase in dimensions and depth with increasing duration of the exposure. (84K) Fig. 2. Stereoscopic images (35) of (a) uncorroded specimen and (b) specimen exposed to salt spray corrosion for 10 days. 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 fitted by the Weibull function (2) 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 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, simulates qualitatively the natural corrosion in coastal environment, it is much more aggressive and causes a very severe corrosion attack in a short time. Currently, there is no direct correlation between the accelerated laboratory salt spray test and the natural corrosion of reinforcing steels such as to assess a realistic duration for the accelerated laboratory salt spray tests. Fig. 4 shows a photograph taken from a building constructed in 1978 at a coastal site in Greece. The corroded reinforcing bars indicated a severe mass loss. The mass loss of the corroded bars shown in Fig. 4 was as high as 18% which corresponds to an exposure of days according to the fitting curve in Fig. 3. The corrosion measured for the mentioned case appeared rather frequently during an extensive investigation on the integrity of older constructions at coastal sites in Greece. Even though the above results are by far not sufficient for establishing exact correlations between laboratory salt spray tests and natural corrosion, they clearly indicate that laboratory salt spray exposures for 40 days and longer are realistic for simulating the natural corrosion damage of steel bars which might accumulate during the service time of reinforced concrete structures at coastal sites. By assuming a uniform production of the oxide layer around the specimen and hence a uniform mass loss, the results of Fig. 3 can be exploited to calculate the reduction of the nominal specimen diameter with increasing duration of the salt spray test. The reduced diameter dr is calculated as (3) where a is the measured mass loss in percent and d is the nominal diameter of the uncorroded specimens