| With modem buildings higher increasingly, as well as fire accidents happen continuously over the past few years, the research and application of building fire retardant materials,especially building fire retardant coating, as one of the effective measures of the prevention and containment of fire accidents, have the very important position. The traditional non-intumescent is of heavy weight,thick coating and low bond strength. As a result,it is likely to fall off in the late. In this paper, the waste aerogel powder produced in the production of aerogel insulation board, due to its propertites of high porosity, low thermal conductivity and high temperature resistance,is used as a new type of fireproof insulation filler to produce cement-based aerogel fire retardant coating,which is lighter,thinner but of excellent fire resistance. The effects of the dosage of aerogel powder on the performances of fire retardant coating are studied. Moreover, the optimization of the performance of fire retardant coatings is exploratory studied by combining the aerogel powder with expanded perlite, sealed pores and hollow resin ball. The influence law of the change of the volume fraction of each thermal insulation component on the thermal conductivity and fire resistance of the aerogel powder-hollow resin ball-sealed pores insulation system is analyzed by the composition triangle. The main research work are as follows:(1) The aerogel powder, as a new kind of fire insulation filler, is used to produce the cement-based aerogel fire retardant coating. The dry bulk density of which is in the range of 527 kg/m3-813 kg/m3 are prepared by changing the dosage of aerogel powder. The effect of the dosage of aerogel powder on the thermal conductivity, fire resistance and bond strength of fire retardant coating is studied. Moreover, the above properties of fire retardant coating are compared with those of expanded perlite coating and foamed cement specimen with similar dry bulk density. The results show that cement-based aerogel fire retardant coating is of good fireproof performances. With the decrease of the dry bulk density from 813 kg/m3 to 527 kg/m3, the thermal conductivity of the coating decreases from 0.227 W/m·K to 0.084 W/m K,which is much lower than that of the expanded perlite coating and foam cement specimen with similar dry bulk density. The fire retardant performance of the coating is strengthened and then weakened with the increase of the aerogel dosage. When the dry bulk density of the coating is 583 kg/m3, the fire resistance of the coating is the best and the fire resistance time is 70 minutes. Compared with the expanded perlite coating and foam cement specimen with similar dry bulk density, the thermal conductivity of the coating is significantly improved. The bonding strength of the coating decreases with the increase of the aerogel dosage and can be effectively improved by the combination of inorganic binder and redispersible latex powder.(2) A kind of thermal insulation system is formed by the combination of the aerogel powder and expanded perlite, the effects of the relative volume fraction of the expanded perlite and the aerogel powder on the thermal conductivity, fire retardant performance and bonding strength of the cement-based coating are studied under the condition of the constant volume of thermal insulation components. The results show that the thermal conductivity and the bonding strength decrease with the increase of the volume fraction of the aerogels. The fire resistant properties are strengthened with the increase of the volume fraction of the aerogel powder.(3) Another kind of thermal insulation system is formed by the combination of the aerogel powder and sealed pores produced by air entraining agent. The effects of the volume fraction of sealed pores on the thermal conductivity, fire retardant performance and bonding strength of the cement-based coatings are stutied under the condition of the constant volume fraction of aerogel powder. The results show that, with the increase of the volume fraction of sealed pores, the thermal conductivity and bonding strength of aerogel-sealed pores composite fire resistant coating decrease and the fire retardant performance of the coating is strengthened and then weakened.(4) The other kind of thermal insulation system is formed by the combination of the aerogel powder, hollow resin ball and sealed pores. The effect law of the changes of every three thermal insulation components volume fraction on the thermal conductivity and fire retardant performance of the cement-based coating thermal are studied by composition triangle under the condition of the constant total volume of all thermal insulation components.And the heat insulation composition ratio of the best fire-resistant properties is determined.The results show that, when the volume fraction of the aerogel powder and sealed pores is lower and the volume fraction of the resin ball is higher than 0.78, the thermal insulation property of the specimens is better and the thermal conductivity of the specimens is lower The specimens are of good high temperature insulation performance when the volume fraction of aerogel powder is between 0.33 and 0.78, and the volume fraction of hollow resin ball and sealed pores is close. |
