本文選題：混凝土　切入點(diǎn)：疲勞　出處：《實(shí)驗(yàn)力學(xué)》2017年04期 　論文類型：期刊論文

【摘要】：混凝土橋梁在服役過程中經(jīng)常同時(shí)承受疲勞荷載和氯離子侵蝕,但現(xiàn)有研究多未考慮疲勞和氯離子侵蝕的耦合作用。本文研究了疲勞荷載與氯鹽侵蝕耦合作用下混凝土中氯離子的擴(kuò)散行為,并運(yùn)用超聲檢測(cè)表征混凝土的疲勞損傷,以建立疲勞損傷與氯離子擴(kuò)散性能之間的關(guān)系。研究結(jié)果表明:隨著疲勞壓應(yīng)力水平提高,超聲參數(shù)表征的混凝土損傷值也逐漸增大;應(yīng)力水平低于0.4時(shí),不同疲勞應(yīng)力水平對(duì)混凝土中氯離子濃度分布沒有明顯影響,氯離子擴(kuò)散系數(shù)甚至略有減小,這應(yīng)是應(yīng)力水平較低時(shí)混凝土中微孔隙和裂縫被壓縮而降低了氯離子的擴(kuò)散能力;應(yīng)力水平為0.5及0.6時(shí),混凝土中氯離子濃度顯著提高,擴(kuò)散系數(shù)明顯增大,并且與應(yīng)力水平呈正相關(guān);超聲參數(shù)表征的混凝土損傷與氯離子滲透性的發(fā)展趨勢(shì)不一致,表明由于混凝土內(nèi)部缺陷分布的不均勻性使得超聲技術(shù)難以定量表征荷載引起的混凝土損傷。
[Abstract]:Concrete bridges are often subjected to both fatigue load and chloride erosion during service. In this paper, the diffusion behavior of chloride ions in concrete under the coupling of fatigue load and chloride erosion is studied, and the fatigue damage of concrete is characterized by ultrasonic detection. In order to establish the relationship between fatigue damage and chloride diffusion property, the results show that the damage value of concrete characterized by ultrasonic parameters increases with the increase of fatigue compressive stress level, and when the stress level is lower than 0.4, Different fatigue stress levels have no obvious effect on the chloride concentration distribution in concrete, and the chloride diffusion coefficient even decreases slightly, which is due to the reduction of chloride diffusion capacity due to the compression of micro-pores and cracks in concrete with lower stress level. When the stress levels are 0.5 and 0.6, the chloride concentration in concrete increases significantly, the diffusion coefficient increases obviously, and it is positively correlated with the stress level, and the damage of concrete characterized by ultrasonic parameters is not consistent with the development trend of chloride ion permeability. It is shown that ultrasonic technique is difficult to quantitatively characterize concrete damage caused by load due to the uneven distribution of internal defects in concrete.
【作者單位】： 長沙理工大學(xué)土木與建筑學(xué)院;長沙理工大學(xué)南方地區(qū)橋梁長期性能提升技術(shù)國家地方聯(lián)合工程實(shí)驗(yàn)室;
【基金】：國家自然科學(xué)基金(51578078) 國家“973”計(jì)劃課題(2015CB057701) 長沙市科技計(jì)劃(K1508020-31) 長沙理工大學(xué)土木工程優(yōu)勢(shì)特色重點(diǎn)學(xué)科創(chuàng)新性項(xiàng)目(16ZDXK10)
【分類號(hào)】：TU528

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