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抗氯离子侵蚀能力的强弱对水泥基材料服役寿命长短有着关键性的影响。本文研究了不同氧化石墨烯(GO)掺量(0%、0.02%、0.04%、0.06%、0.08%、0.10%,质量分数)在干湿交替氯盐环境下对水泥砂浆抗氯离子侵蚀性能的影响,分析了不同GO掺量下自由氯离子浓度与水泥砂浆抗氯离子侵蚀性能之间的关系,并利用扫描电子显微镜从微观角度分析水泥砂浆的抗侵蚀性能。结果表明:GO能显著提高水泥砂浆的抗氯离子侵蚀能力,最佳掺量范围为0.04%~0.06%;在同一钻孔深度处,水泥砂浆内的自由氯离子浓度随着GO掺量的增加先降低后升高;GO能有效调节水泥砂浆的微观形貌,减少内部孔隙产生,密实结构,提高水泥砂浆抗氯离子侵蚀能力。 相似文献
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硫酸盐侵蚀是影响混凝土耐久性的重要因素之一.通过外观、抗压抗蚀系数、抗折抗蚀系数和膨胀率等宏观性能,研究了干湿循环作用下混凝土抗硫酸钠和抗硫酸镁侵蚀性能,并基于侵蚀产物相和孔结构结果分析了粉煤灰对其抗侵蚀性能的影响机制.结果表明:在硫酸盐和干湿循环两者共同耦合作用下,干湿循环的作用是促进硫酸盐的结晶,加速混凝土破坏.粉煤灰掺量为15%时砂浆抗侵蚀的性能最好,随着粉煤灰掺量继续增加,砂浆的抗硫酸盐侵蚀性能明显降低.与硫酸钠溶液劣化规律相对比,镁离子的存在减缓了砂浆的劣化破坏速度,砂浆的盐结晶损伤减轻,其原因在于侵蚀溶液中的氢氧根离子会与镁离子反应生成氢氧化镁沉淀在砂浆表面,抑制了硫酸根离子的向内扩散. 相似文献
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为探索经受冻融循环后的钢纤维混凝土在氯盐环境作用下的耐久性能,通过对冻融循环不同次数后的钢纤维混凝土试件开展氯离子侵蚀试验,分析了钢纤维掺量、冻融循环次数等因素对氯盐侵蚀环境下钢纤维混凝土耐久性的影响规律并探索了冻融损伤对钢纤维混凝土氯离子侵蚀性能的影响机理.研究结果表明:钢纤维掺量在0~1.5%范围内,钢纤维掺量越大,相同渗透深度处混凝土氯离子扩散系数越小,混凝土抵抗氯离子侵蚀的性能越好;冻融循环次数越大,钢纤维混凝土氯离子扩散系数越大,混凝土抵抗氯离子侵蚀的性能越差. 相似文献
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为研究不同质量掺量三乙醇胺(TEA)作助磨剂对蔗渣灰颗粒特性的影响,通过方孔筛筛余量、粒径分布、比表面积和颗粒形貌测试对蔗渣灰颗粒特性进行表征,研究蔗渣灰颗粒特性对蔗渣灰砂浆强度及抗氯盐侵蚀性的影响。结果表明,TEA可优化蔗渣灰颗粒粒径分布,在最佳质量掺量0.08%条件下,<32 μm的颗粒占比增加8.2个百分点,比表面积可提升至5.503 5 m2/g,颗粒形貌更趋于圆球状。同时,蔗渣灰砂浆的强度和抗氯盐侵蚀性能随着TEA掺量的增加呈现先增后降的变化规律,TEA在0.08%(质量分数)最佳掺量时,蔗渣灰砂浆的抗压强度相比于普通水泥砂浆提升19.88%,氯离子扩散系数下降79.63%。通过X射线衍射和压汞孔分析测试揭示了蔗渣灰颗粒特性对蔗渣灰砂浆性能的影响机理,研究表明:经过TEA助磨剂优化后的蔗渣灰火山灰反应活性得到提升,蔗渣灰砂浆基体中生成更多水化产物,提高了密实度;优化后的蔗渣灰颗粒充分发挥了填充效应,降低蔗渣灰砂浆的孔隙率,提高了蔗渣灰砂浆的强度和抗氯盐侵蚀性能。 相似文献
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《应用化工》2022,(9):2182-2186
以醋酸乙烯-乙烯共聚物(VAE)、水泥、石英砂等材料,制备出一种混凝土路面修复用聚合物改性水泥砂浆,研究了VAE掺量对水泥砂浆流动度、强度、干缩、抗碳化特性及界面粘附性的影响,并采用扫描电镜(SEM)观测其微观结构。结果表明,抗折强度、界面粘结强度随VAE掺量的增加先增加后降低,表明VAE可以提高水泥砂浆的柔韧性、界面粘结强度;随着VAE掺量的增加,1 h流动度损失率、干缩率、碳化深度逐渐降低,表明VAE可以改善水泥砂浆的保水能力、干缩率、抗碳化侵蚀能力;SEM测试结果显示,聚合物胶膜填充于砂浆内部的有害孔隙,裹附于水化产物表面,提高了砂浆的密实程度。综合考虑水泥砂浆物理力学及经济性能,推荐VAE作为改性聚合物的合理掺量为胶凝材料用量的8%。 相似文献
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我厂3号回转窑(Φ4m×60m)生产线在1996年年底由SP窑(产量912t/d)改为NSP窑(产量1320t/d),预分解系统为四级旋风预热器带离线式分解炉 相似文献
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乙烯酮(双乙烯酮)是十分重要的化工中间体,其下游产品较多。江苏某化工厂开发生产乙烯酮(双乙烯酮)下游产品三十多个,年生产规模三万多吨,是国内以乙烯酮(双乙烯酮)为中间体生产精细化学品的综合骨干企业。针对乙烯酮(双乙烯酮)下游产品废水特点,该厂结合企业实际,开展了产品优化,结构调整,清洁生产,资源循环利用,节水降耗等工作,从源头削减了污染物的生产。同时投资二千多万元新建预处理装置三套,6000m3/d废水生化处理装置一套,使全厂乙烯酮(双乙烯酮)下游产品的废水得到了有效的治理。 相似文献
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The objective of the study was to explore the effect of the degree of deacetylation (DD) of the chitosan used on the degradation rate and rate constant during ultrasonic degradation. Chitin was extracted from red shrimp process waste. Four different DD chitosans were prepared from chitin by alkali deacetylation. Those chitosans were degraded by ultrasonic radiation to different molecular weights. Changes of the molecular weight were determined by light scattering, and data of molecular weight changes were used to calculate the degradation rate and rate constant. The results were as follows: The molecular weight of chitosans decreased with an increasing ultrasonication time. The curves of the molecular weight versus the ultrasonication time were broken at 1‐h treatment. The degradation rate and rate constant of sonolysis decreased with an increasing ultrasonication time. This may be because the chances of being attacked by the cavitation energy increased with an increasing molecular weight species and may be because smaller molecular weight species have shorter relaxation times and, thus, can alleviate the sonication stress easier. However, the degradation rate and rate constant of sonolysis increased with an increasing DD of the chitosan used. This may be because the flexibilitier molecules of higher DD chitosans are more susceptible to the shear force of elongation flow generated by the cavitation field or due to the bond energy difference of acetamido and β‐1,4‐glucoside linkage or hydrogen bonds. Breakage of the β‐1,4‐glucoside linkage will result in lower molecular weight and an increasing reaction rate and rate constant. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3526–3531, 2003 相似文献
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Conclusions It is significant that the purification on a single passage of viscose through porous ceramic corresponds to the result of a two-stage filtration of it in industrial filter-presses with standard fillings.Kiev Combine. Kiev Technological Institute of Light Industry. Translated from Khimicheskie Volokna, No. 3, pp. 20–22, May–June, 1969. 相似文献
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A refined nonlinear value of the main parameter of a material, i.e., the elongation modulus versus the instant temperature value, was suggested for introduction into the computational algorithm of tempering stresses. 相似文献