Research On Performances Optimization Of Vitrified Microsphere Thermal Insulation Mortar

In recent years, with the rapid development of construction industry in our country, there is more and more attention on building energy conservation. The preparation of high performance thermal insulation materials is extremely urgent, in order to solve the energy waste, and improve the living environment. Inorganic insulation material is a new type of exterior wall thermal insulation material, which has more unique superiorities than organic thermal insulating material. But the thermal insulation mortar still have some flaws in itself, so more research is needed.In this paper, Portland cement, fly ash and hydrated lime was used as cementitious material, and vitrified microsphere as aggregate, with emulsion powder, cellulose ethers, fiber, to develop the vitrified microsphere thermal insulation mortar. On the basis of vitrified microsphere thermal insulation mortar, adopting foaming technology can prepare the high-performance foamed vitrified microsphere thermal insulation mortar. The hydrophobicity of the thermal insulation mortar was subsequently enhanced to improve its long-term performance.The results show that the stirring time has remarkable influence on the performance of thermal insulating mortar, 3 minutes would be the best choice. Fly ash replacing equally cement can increase the fluidity and reduce the apparent density, and the dosage of fly ash should preferably not to be more than 20%. When partial cement is replaced by hydrated lime, the fluidity is effectively improved, the thermal insulation performance is increased. The re-dispersible emulsion powder can significantly improve bonding strength and flexural strength of thermal insulation mortar, when the content of re-dispersible emulsion powder reaching 2 percent. Cellulose ethers can raise caking, improve water conserve property, the optimum mixing proportions of cellulose ethers is 0.5%. The suitable content of polypropylene fibers is about 0.6percent.When the cementitious material to aggregate ratio reaching 1kg:8L, properties of the normal vitrified expanded perlite thermal insulation mortar meets Ⅱ-type mortar requirements of GB/T 20473-2006.The effect of different preparation methods on foam inorganic thermal insulation mortar were investigated in this paper. The preparation methods of foamed vitrified microsphere thermal insulation mortar include mix-foaming process and pre-foaming process. When the cementitious material to aggregate ratio reaching 1kg:6L, properties of the foamed vitrified microsphere thermal insulation mortar meets Ⅰ-type mortar requirements of GB/T 20473-2006. The addition of suitable amount of foam could largely improve thermal insulation performance and reducing apparent density, the minimum thermal conductivity of foamed vitrified microsphere thermal insulation mortar is 0.049 W/(m·K), far smaller than that requested in the standard.Three kinds of measures to improve hydrophobicity of thermal insulation mortar containing vitrified microsphere were presented as follows: brushing liquid hydrophobic agent on the surface of thermal insulation mortar,adding powdery hydrophobic agent to thermal insulation mortar and the composite methods. Brushing liquid hydrophobic agent which dilution ratio is 10, leads to formation of protective adsorbed hydrophobic film on the surface of thermal insulation mortar; the volume water absorption rate decreased due to the adding of powdery hydrophobic agent, which content is 0.5 percent; the composite methods have better effect.