共查询到19条相似文献,搜索用时 717 毫秒
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主要研究了外界环境中硫酸盐对混凝土的侵蚀破坏,从物理硫酸盐侵蚀和化学硫酸盐侵蚀两方面论述了混凝土外部硫酸盐侵蚀的类型及破坏特征,并对外部硫酸盐侵蚀过程中石膏的形成作为膨胀源进行了讨论,为混凝土性能的进一步研究提供了技术支持。 相似文献
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研究了硫酸盐环境中混凝土的侵蚀破坏,着重考察了硫酸盐侵蚀中混凝土质量损伤、动弹性模量变化、表观损伤及微裂纹分布。同时对比研究了粉煤灰、矿渣及粉煤灰矿渣复掺对混凝土硫酸盐侵蚀的影响。 相似文献
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为了研究埋置在土中与浸泡在溶液中两种侵蚀环境下硫酸盐对混凝土试件侵蚀破坏程度的差别,通过设置3种水胶比,侵蚀环境为土壤埋置和溶液浸泡的6组对照试验,分析混凝土试件在不同环境下的破坏情况,得到了埋置土中与浸泡溶液中对混凝土试件侵蚀破坏的差异。结果表明:在侵蚀龄期达到300 d时,浸泡在硫酸钠溶液中的试件质量损失量是埋置于土中试件的2倍,而埋置于土中试件的抗压强度减少量是浸泡于溶液中试件的2.5倍,埋置于土中的试件在遭受硫酸盐侵蚀破坏时,不仅仅只是受单一的硫酸盐侵蚀破坏,还包括干湿循环等破坏,其破坏程度要远远大于硫酸盐溶液浸泡下的侵蚀破坏程度。这对于研究硫酸盐溶液侵蚀试验得出的破坏规律和实际处于硫酸盐侵蚀环境下建筑物的侵蚀破坏规律的相关性具有重要的参考意义,更有效的将试验结果应用于实际工程。 相似文献
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从物理侵蚀和化学侵蚀两方面论述硫酸盐侵蚀的破坏机理,综述了混凝土受硫酸盐侵蚀时,其自身特性及工作环境对侵蚀破坏的影响,结合物理侵蚀以及化学侵蚀作用机理,对干湿循环与连续浸泡方法的试验结果进行可能性的分析,并对混凝土硫酸盐侵蚀研究中存在的问题进行了总结。 相似文献
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混凝土硫酸盐侵蚀及防护研究进展 总被引:1,自引:0,他引:1
《混凝土》2017,(3)
工程中混凝土由于耐久性不足所引起的结构破坏常有报道,在我国沿海及内陆地区,硫酸盐侵蚀是引发这一问题的主要原因之一。硫酸盐侵蚀有两个途径,其一,在环境影响下硫酸盐从盐溶液中析出晶体产生结晶压力破坏结构;其二,侵蚀介质与水泥水化矿物发生化学反应生成膨胀性矿物导致结构性能劣化。通过分析已有混凝土抗硫酸盐侵蚀方面的研究成果,综述普通混凝土在硫酸盐环境中受侵蚀机理、耦合作用下抗硫酸盐腐蚀行为及混凝土在硫酸盐侵蚀环境下力学性能变化。同时,对今后的研究方向做了简要讨论。 相似文献
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碳硫硅钙石型硫酸盐侵蚀(简称TSA)通过化学反应实现对混凝土的破坏,破坏特点是将混凝土中内部胶凝材料通过化学反应变成没有凝结力的糊状白色粉末,以此破坏其使用性能。本文概述了混凝土TSA型硫酸盐侵蚀机理、发生条件和相应的预防措施,比较完整地总结了国内外混凝土TSA型侵蚀研究情况,并对今后的研究方向做出了展望。 相似文献
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干湿循环对混凝土硫酸盐侵蚀的影响 总被引:1,自引:0,他引:1
硫酸盐侵蚀对混凝土的耐久性有重要影响,但在实际工程中混凝土往往不是处于硫酸盐单一的作用环境中,混凝土往往受到外界环境条件和硫酸盐侵蚀双重因素的作用,如干湿交替等.阐述了国内外对于环境因素中的干湿交替对混凝土硫酸盐侵蚀的研究现状,并通过试验证明了干湿循环对混凝土硫酸盐侵蚀的加速作用,为以后的研究提供一些建议. 相似文献
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Ninghui LIANG Jinwang MAO Ru YAN Xinrong LIU Xiaohan ZHOU 《Frontiers of Structural and Civil Engineering》2022,16(3):316
To study the damage evolution behavior of polypropylene fiber reinforced concrete (PFRC) subjected to sulfate attack, a uniaxial compression test was carried out based on acoustic emission (AE). The effect of sulfate attack relative to time and fiber hybridization were analyzed and the compression damage factor was calculated using a mathematical model. The changes to AE ringing counts during the compression could be divided into compaction, elastic, and AE signal hyperactivity stages. In the initial stage of sulfate attack, the concrete micropores and microcracks were compacted gradually under external load and a corrosion products filling effect, and this corresponded with detection of few AE signals and with concrete compression strength enhancement. With increasing sulfate attack time, AE activity decreased. The cumulative AE ringing counts of PFRC at all corrosion ages were much higher than those for plain concrete. PFRC could still produce AE signals after peak load due to drawing effect of polypropylene fiber. After 150 d of sulfate attack, the cumulative AE ringing counts of plain concrete went down by about an order of magnitude, while that for PFRC remained at a high level. The initial damage factor of hybrid PFRC was −0.042 and −0.056 respectively after 150 d of corrosion, indicating that the advantage of hybrid polypropylene fiber was more obvious than plain concrete and single-doped PFRC. Based on a deterioration equation, the corrosion resistance coefficient of hybrid PFRC would be less than 0.75 after 42 drying−wetting sulfate attack cycles, which was 40% longer than that of plain concrete. 相似文献
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Concrete structures in service may be suffer from sulfate attack, which may lead to the deterioration of both static and dynamic properties of concrete, and therefore jeopardize their performance in earthquake events. To predict the seismic performance of sulfate-damaged concrete structures, the rate-dependent strength, deformation behavior and energy absorption capacity of concrete specimens under sulfate attack were investigated. First, half of the specimens were initially cured under sulfate attack for 4 months and the other half of the specimens were cured in a room environment for comparison. Then axial compressive experiments for concrete specimens with different strain rates were carried out. Experimental results show that sulfate attack had a significant impact on the dynamic properties of concrete. Sulfate attack makes concrete strength more sensitive to strain rate. With increasing strain rates, the peak strain and energy absorption capacity of control and sulfate attacked concrete tend to increase, but they are greatly decreased by disruptive expansion and chemical deterioration induced by sulfate attack. Finally, the failure phenomenon was shown and the damage mechanism of specimens was discussed. 相似文献
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Sulfate attack is one of several chemical mechanisms of concrete deterioration. Exposure of concrete structures in the sulfate environments may lead to detrimental chemical, microstructural, and physical changes in the concrete matrix, resulting in serious deteriorations and service life reduction. Partial replacement of cement with slag is one of the efficient methods for improving concrete resistance against sulfate attack. In this paper the performance of copper slag contained concrete in sulfate solution is investigated. In this regard, an experimental study including expansion measurements, compressive strength degradation and microstructural analysis were conducted in sulfate solution on concretes made by replacing 0%, 5%, 10% and 15% of cement with copper slag waste. The results of this study emphasized the effectiveness of copper slag replacement in improving the concrete resistance against sulfate attack. 相似文献
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多孔混凝土在干湿交替作用下加速硫酸盐侵蚀的耐久性评价 总被引:1,自引:0,他引:1
研究了干湿交替作用下加速硫酸盐侵蚀对植生型多孔混凝土耐久性的影响.采用正交实验方法,研究了净浆水胶比、矿粉掺量和骨料粒径三种因素对多孔混凝土抗硫酸盐侵蚀性以及对抗压强度的影响.试验通过将测量的超声波波速换算为相对动弹模量以评价多孔混凝土的硫酸盐侵蚀破坏程度.实验结果表明,在相同空隙率情况下,骨料粒径越小,抗硫酸盐侵蚀性能越好;水胶比在0.25~0.29的范围内,净浆水胶比越大,抗硫酸盐侵蚀性能越好;磨细矿粉掺量大于20%时,不利于提高多孔混凝土的抗硫酸盐侵蚀性能. 相似文献