碳纳米管水泥基材料的制备及其热膨胀系数研究
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摘要
为了解决大体积混凝土内部温度应力和裂缝问题,采用PVP分散剂、磁力搅拌和超声分散等方法制备碳纳米管水泥基材料。观察不同碳纳米管掺量水泥基材料在16～600℃热膨胀系数的变化,从微观尺度进行机理分析,并通过力学性能进行验证。结果表明,不同碳纳米管掺量时热膨胀系数变化趋势相似,掺量为0.3%时,材料在正向、负向的热膨胀系数始终在其它掺量之下,体积膨胀最小,收缩最大。这说明碳纳米管掺量为0.3%时,水化反应充分,密实度显著提升,使其内部裂缝减少,温度应力减弱,宏观上表现为抗压、抗折强度最高。
In order to solve the internal temperature stress and crack problem of mass concrete,carbon nanotube cement-based materials were prepared by PVP dispersant,magnetic stirring and ultrasonic dispersion method. Observe the change of thermal expansion coefficient at 16 ～600 ℃ for different proportions of carbon nanotube cement base. The pore size distribution map and scanning electron micrograph were used to analyze the mechanism from the microscopic scale and verified by mechanical properties.The results show that the trend of each proportion is similar,but when the dosage is 0.3% of cement,the coefficient of thermal expansion in the positive and negative directions is always under other dosages,the volume expansion is the smallest,and the shrinkage is the largest. This indicates that the hydration reaction is sufficient when the dosage is 0.3%,and the compactness is remarkably improved,so that the internal cracks are reduced and the temperature stress is weakened,and macroscopic exhibition is the highest in the compressive and flexural strength.
In order to solve the internal temperature stress and crack problem of mass concrete,carbon nanotube cement-based materials were prepared by PVP dispersant,magnetic stirring and ultrasonic dispersion method. Observe the change of thermal expansion coefficient at 16 ～600 ℃ for different proportions of carbon nanotube cement base. The pore size distribution map and scanning electron micrograph were used to analyze the mechanism from the microscopic scale and verified by mechanical properties.The results show that the trend of each proportion is similar,but when the dosage is 0.3% of cement,the coefficient of thermal expansion in the positive and negative directions is always under other dosages,the volume expansion is the smallest,and the shrinkage is the largest. This indicates that the hydration reaction is sufficient when the dosage is 0.3%,and the compactness is remarkably improved,so that the internal cracks are reduced and the temperature stress is weakened,and macroscopic exhibition is the highest in the compressive and flexural strength.
引文
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[2]高桂波,钱春香,朱晨峰,等.粉煤灰对混凝土热膨胀系数的影响[J].东南大学学报(自然科学版),2006(S2):185-190.
[3]唐倩兰,黄俊,田国鑫.碳纳米管分散性及其水泥基复合材料力学性能的研究进展[J].功能材料,2017(6):6042-6049.
[4]姚武,左俊卿,吴科如.碳纳米管-碳纤维/水泥基材料微观结构和热电性能[J].功能材料,2013(13):1924-1927.
[5]戎志丹,虞焕新,林发彬.低水胶比条件下水泥基复合材料的微结构形成机理[J].武汉理工大学学报,2013(4):6-10.
[6]Honorio T,Bary B,Benboudjema F.Thermal properties of cement-based materials:Multiscale estimations at early-age[J].Cement and Concrete Composites,2018,87:205-219.
[7]Zhou C,Shu X,Huang B.Predicting concrete coefficient of thermal expansion with an improved micromechanical model[J].Construction and Building Materials,2014,68:10-16.
[8]徐洪国,水中和,章瑞,等.偏高岭土对水泥石热膨胀性能的影响[J].硅酸盐通报,2011,30(2):278-282.
[9]Gao Y,De Schutter G,Ye G,et al.A microscopic study on ternary blended cement based composites[J].Construction and Building Materials,2013,46:28-38.