| The construction industry is an important pillar of China's national economic development.With the rapid development of urban-rural integration process in china,the consumption of building materials and energy will be increased.As one of the three energy consumption,building energy consumption will also surpass the other two major energy consumption for the first time and becoming largest terminal energy consumption unit in china.Therefore,the preparation of green and energy-saving building materials is of great significance to promote the sustainable development of China's economy,which will also promote the development of China's construction materials in the direction of high performance and environmental protection.Energy storage building materias are used to add energy storage materials to the building materials,which to play the role of tempering,thus reducing building energy consumption.In this paper,the CA-SA eutectic was adsorbed into ceramsite to prepare CA-SA/ceramics composite heat storage material,and encapsulated by epoxy resin.Then,the encapsulated CA-SA/ceramic composite heat storage material was mixed with gypsum to prepare water-resistant phase change heat storage gypsum board.Using steel slag and metakaolin as inorganic mineral admixtures and combining different curing conditions to modify the gypsum to obtain the material mix ratio and process conditions for the best comprehensive performance of gypsum.The effects of steel slag and metakaolin with different substitution amounts and process conditions on the physical properties of gypsum were studied.XRD and SEM were used to analyze the phase and microstructure of gypsum.The experimental results show that the optimal substitution amounts of steel slag and metakaolin are 10%and 5%respectively.At this time,the dry(wet)compressive strength and softening coefficient are 25.5 MPa,11.1 MPa,and 0.44,respectively.Compared with gypsum,they increased by 12.6%,60.8%,and 41.9%,respectively.When the gypsum cementitious material was cured at 60°C for 4 h,its wet compressive strength and softening coefficient were 14.8 MPa and 0.73,respectively,which was 132.7%and 138.7%higher than that of the blank gypsum,respectively,and modified gypsum has good water resistance.CA-SA was prepared by a combination of theoretical prediction and experiment.The theoretical eutectic mass ratio,eutectic melting point and eutectic latent heat of CA-SA were 90.7:9.3,26.67°C and 121.3J/g,respectively.The DSC results show that the eutectic melting point and eutectic latent heat of CA-SAwere 28.53°C and135.55J/g,respectively.It can be seen that theoretical calculations have a good guiding role.After 600 cycles of thermal cycling,the phase transition temperature and latent heat of phase change of CA-SA were 26.53°C and 130.76J/g,respectively,which were not significantly different from those before the non-circulation.FT-IR results showed that the vibration absorption bands of the characteristic functional groups in the CA-SA heat storage material were almost the same before and after 600cycles.Therefore,it can be seen that both structure stability and thermal stabilitythe are good of binary eutectic.DSC analysis showed that the phase transition temperature and phase change enthalpy of CA-SA/ceramic heat storage material were 28.95°C and 43.76 J/g.FT-IR analysis showed that the vibration absorption band of the characteristic functional groups in the composite heat storage material is the same as that of the binary eutectic.Therefore,the binary eutectic is embedded in the pores of the ceramsite.100 thermal cycles of CA-SA/ceramic composite heat storage material coated with epoxy resin and polymer cement,respectively.The results show that the surface of the epoxy-coated composite heat storage material is intact,and the coating on the surface of the composite heat-storage material coated with polymer cement was cracked and peeled off.The uncovered CA-SA/ceramic composite heat storage material shows a leakage phenomenon.Therefore,epoxy resin is preferred as a coating material.Epoxyresin-coatedCA-SA/ceramiccompositeheatstoragematerial incorporated into gypsum cementitious material for heat storage gypsum board.The experimental results show that when the dosage of CA-SA/ceramics composite heat storage material is 25%,the dry(wet)compressive strength and softening coefficient of the water-resistant energy-storage gypsum board are 8.74 MPa,5.35 MPa,and 0.61,respectively.Softening coefficient increased by 96.8%compared to blank plasterboard.Therefore,the water-resistant phase change energy-storage gypsum board has better water resistance.At this time,thermal conductivity,specific heat capacity and heat storage coefficient of the water-resistant energy storage gypsum board were 0.555W/(m?K),1.428J/(g.?)and 8.9W/(m~2K),respectively.When the amount of CA-SA/ceramics composite heat storage material increases from 0%to25%,the temperature of experimental model interior increased from 22°C to 30°C and the corresponding time changed from 1430s to 2164s.Therefore,it can be seen that the water-resistant energy storage gypsum board has a better effect of energy storage and temperature control. |
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