矿物和纳米材料对活性粉末混凝土性能的影响

    Influence of Minerals and Nanomaterials on the Properties of Reactive Powder Concrete

    • 摘要: 这是一篇陶瓷及复合材料领域的论文。利用硅粉、偏高岭土和纳米材料制备了活性粉末混凝土,并对矿物成分和纳米材料对活性粉末混凝土基本特性的影响规律进行了研究。硅粉和偏高岭土按照固定比例掺入,纳米二氧化硅和纳米氧化铝则分别按照水泥质量0.5%、1%、2%和3%的比例进行掺入。通过新拌混凝土的密度和流动度实验以及不同龄期下的强度实验对改性后的活性粉末混凝土的基本特性进行测试,结果表明随着纳米材料的掺入,混凝土的密度逐渐增加,而流动度则不断减小;抗压强度和抗折强度随着纳米材料掺入量的增加先增后减,由此得出纳米材料的较优掺量为1%~2%。高温实验结果表明活性粉末混凝土的抗压强度和抗折强度随着温度先增后减,较佳温度为200 ℃;温度导致的强度下降的速度为CSS>CSA>CMA>CMS。此外,SEM分析表明高温会导致混凝土内部出现劣化。

       

      Abstract: This is an essay in the field of ceramics and composites. Reactive powder concrete was prepared using silica fume, metakaolin and nanomaterials, and then the influence of mineral composition and nanomaterials on the basic characteristics of reactive powder concrete was studied. Silica fume and metakaolin are mixed in fixed proportions, while nano-silica and nano-alumina are mixed in proportions of 0.5%, 1%, 2% and 3% of the cement mass, respectively. The basic characteristics of the modified reactive powder concrete were tested through the density and fluidity experiments of fresh concrete and the strength tests were conducted at different curing ages. The results showed that with the incorporation of nanomaterials, the density of concrete gradually increased, whilethe fluidity continues to decrease; the compressive strength and flexural strength of samples first increase and then decrease with the increase of nanomaterials, and it is concluded that the optimal dosage of nanomaterials is 1%~2%. The high temperature test results show that the compressive strength and flexural strength of reactive powder concrete increase first and then decrease with the temperature, the best temperature is 200 ℃; the rate of strength decrease caused by temperature is CSS>CSA>CMA>CMS. In addition, SEM analysis also shows that high temperature will cause deterioration of the interior of the concrete.

       

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