复合相变纳米元件用于大体积混凝土控温研究

Research on Complex NanoElement Used for Controlling Temperature in Mass Concrete

摘要:

将有机膨润土与癸酸相变控温储能纳米元件处理成为砂粒状的相变砂，有利于提高其与水泥混凝土的相容性.探讨了相变砂细度、掺量对混凝土和易性、强度及耐久性的影响；采用模拟大体积混凝土的方法研究了相变砂的控温效果；采用Super SAP分析方法计算了大体积混凝土内部温度场分布.结果表明: 采用乳液和高强水泥包覆相变控温储能纳米元件形成的相变砂，其与混凝土组分的和易性较好；控制相变砂的细度模数为中粗砂范围，并适当增加减水剂的掺量，在相变砂代砂25%时，可以使掺相变砂的混凝土基本达到基准混凝土坍落度和强度的要求；相变砂的掺入对混凝土的粘聚性、保水性无不良影响；相变砂掺入过多将使混凝土的坍落度和强度下降明显；混凝土电通量试验表明,适量掺入相变砂，对混凝土的耐久性无不良影响.模拟大体积混凝土温升试验表明,掺入相变砂后大体积混凝土中心最高温度为44 ℃，较基准试样降低了4.5 ℃；相变砂只需在大体积混凝土中心部分掺加，大体积混凝土中心温度超过45 ℃的体积占大体积混凝土总体积的体积分数随混凝土尺寸的增大而增大.

Abstract:

Complex nanoelements were made of organic betoniescapric acid for controlling temperature and energy saving.They were managed to sand like grains named phase change sand to enhance their consistent with raw materials of concrete.The influence of particle size distribution of phase change sand and its content on workability,strength and durability of concrete were studied.The method of simulating mass concrete was adopted to study effect of controlling temperature of phase change sand.Super SAP analysis method was introduced to calculate temperature distribution of mass concrete.The results show that phase change sand made of complex nanoelements enwrapped with latex and high strength cement consistent good with raw materials of concrete.Concrete with phase change sand can satisfy workability and strength when the fineness of phase change sand is middle to coarse,the content of water reducing agent is increased properly,and the substitution quantity of phase change sand for fine aggregate reaches 25%.Phase change sand doesn’t bring bad conglutination ability and bad water holding ability in lower content whereas it will bring lower fluidity and lower strength of concrete in higher content.The results of electric flux test for concrete show that phase change sand doesn’t affect durability of concrete in proper content.The test of simulating of temperature moving up in mass concrete show that the highest temperature in center is 44 ℃ which reduces 4.5 ℃ compared to that in norm concrete.Phase change sand needs to be added in center of mass concrete.The volume percent of center where higher than 45 ℃ increases with dimension of mass concrete.