定形PEG/SiO2/石墨复合相变蓄热混凝土制备及性能研究

为制备性能优异的相变蓄热混凝土,试验确定了定形PEG/SiO2/石墨复合相变蓄热骨料中相变材料的组成比例和制备工艺,并研究了相变蓄热骨料对混凝土力学性能和热工性能的影响。结果表明,相变材料中PEG含量为80%,石墨掺量为6%时,相变材料在具有合适相变温度和相变焓的同时,有良好的导热性能;相变蓄热骨料的合适吸附时间和温度分别为3 h和80℃,经表面封装后的相变蓄热骨料具有优异的稳定性。相变蓄热骨料虽然降低了混凝土的抗压强度和导热系数,但延缓了水泥水化热造成的温度升高,延缓了放热速率,能防止温度应力造成的混凝土开裂,且能明显改善混凝土的储热性能,综合考虑相变蓄热骨料替代率不宜大于80%。

Study on Preparation and Properties of Stationary PEG/SiO2/Graphite Composite Phase Transition Thermostorage Concrete

In order to prepare the excellent phase transition thermostorage concrete,the composition ratio and preparation technology of the phase transition material in the fixed form PEG/SiO2/graphite composite phase transition thermostorage concrete were determined by experiment,and the influence of phase transition thermostorage concrete on the mechanical properties and thermal properties of concrete was studied.The results show that when the PEG content in the phase transition material is 80%and the graphite content is 6%,the phase transition material has good thermal conductivity at the same time as suitable phase transition temperature and phase transition enthalpy.The suitable adsorption time and temperature of the phase transition thermostorage concrete are 3 h and 80°C respectively.The phase transition thermostorage concrete after surface encapsulation has excellent stability.Although the phase transition thermostorage concrete reduces the compressive strength and thermal conductivity of the concrete,it delays the temperature increase caused by the hydration heat of the cement,delays the heat release rate,prevents the concrete cracking caused by the temperature stress,and can significantly improve the concrete heat storage performance.The substitution rate of thermostorage aggregate should not be greater than 80%.