Study On Cement-based Organic-inorganic Composite Thermal Insulation Materials For Exterior Wall

This paper studied the preparation of a kind of organic-inorganic composite exterior wallthermal insulation material with the purpose of existing problems of exterior wall thermalinsulation material. This article aimed at studying the effect of component materials on thepreparation of cement-based organic-inorganic exterior wall insulation materials. Moreover,the material proportion and performance optimization were optimized to get insulationmaterials with high mechanical properties, good thermal insulation performance,environmental friendly, energy conservation and A2level fire rating.(1) The close water contact angle of modified EPS particles modified by polymeremulsion was44.5°. The water absorption of vitrified microsphere modified by organicsilicon water-repellent agent was reduced by38.44%. And the water absorption of vitrifiedmicrosphere modified by thermosetting phenolic resin was reduced by66.23%. Themodification effect of the latter was superior to that of the former. Modification insulationaggregate (EPS particle and vitrified microsphere) could effectively improve mechanicalstrength and reduce thermal conductivity of insulation materials. In addition, the optimalinsulation aggregate proportion test was namely the minimum amount of cement required whenthe ratio of vitrified microsphere to total insulation aggregates (the ratio of vitrifiedmicrosphere) was0.65.(2) All properties of insulation board could meet the requirements: especially dry densitycould be about300kg/m3, when the ratio of cement to insulation aggregates was below10.The ratio of water to cement would decrease the strength of insulation material, and the moresuitable ratio of water to cement was from0.45to0.55. Admixtures could improve the overallperformance of insulation materials more effectively. The dosage of cellulose ether was in therange of0.40%to0.60%, water reducer and air entraining agent were approximately at0.55%and0.20%respectively. The optimized proportion was that the ratio of cement to totalinsulation aggregates was9, the ratio of vitrified microsphere was0.65, the ratio of water tocement was0.50, the dosage of water reducer was0.50%, the dosage of cellulose ether was0.40%, and the air-entraining agent content was0.30%. The comprehensive performance wasthat the value of flexural strength, compressive strength, dry density, the thermal conductivity, soften coefficient, water content, water absorption, and pressure off ratio were0.55MPa,0.74MPa,361kg/m3,0.050W/(m·K),0.93,4.30%,4.76%and1.35, respectively.(3) The water resistance and dry shrinkage of insulation materials adding emulsifiedasphalt were stronger and lower. Furthermore, disperse latex powder could improve theviscosity of thermal insulation material, but its dry density would be increased significantly.Therefore, compound air-entraining agent, cellulose ether, emulsified asphalt with powdercould improve the properties of insulation materials, such as mechanical strength, toughness,water resistance. In addition, in order to guarantee that the air-entraining agent could introducetiny air bubbles more effectively, the preparation technology was carried on revolution speed at125r/min, rotation speed at285r/min,20℃and5min. And the best ratio of modifying agentwas that the dosages of air-entraining agent, cellulose ether, emulsified asphalt and powderwere0.20%,0.20%,8%and3%, respectively.(4) In this cement-based EPS/vitrified microsphere composite thermal insulation material,with0.3%fiber, its toughness, compressive strength and flexural strength could increase by8%,42%and56%, respectively. Moreover, Sulphoaluminate cement mixed with20%Portlandcement could reduce the cost of cement-based EPS/vitrified microsphere composite exteriorwall insulation materials. In addition, fly ash and slag could improve the performances ofthermal insulation material. And the best proportion was as follows:80%cement,15%fly ash,and5%slag.