Study On Freezing-thawing Environment Effect Of Polymer Cement Mortar In External Thermal Insulation Composite Systems

External thermal insulation composite is the efficient thermal insulation and energysaving, that is, in order to achieve the purpose of thermal insulation. As is known to all, theexterior metope as the surface of the building must be subjected to all influence of climate,such as heat-cold exchange, rain and wind, etc. The environment effect results in qualityproblem of external thermal insulation composite systems, such as cracks, empty drum, falloff. The engineering quality of external thermal insulation composite systems issues thedurability of wall body and structure. Therefore, this paper discussed the performance ofthe polymer cement mortar in external thermal insulation composite systems, analyzedfreezing and thawing environment effect on polymer cement mortar flexural strength,compressive strength and tensile adhesive strength. This study has its important practicalsignificance of engineering.According to the temperature change in the environment of cold region, and thesituation of the indoor experiment study, the effect of the freezing and thawingenvironment to polymer cement mortar mechanical characteristics of external thermalinsulation composite systems is analyzed in this paper. The main work includes:(1)Mixing ratios of common polymer cement mortar (polyvinyl alcohol,re-disappeared powders, cellulose, sand and cement) were selected, and the flexuralstrength, compressive strength and tensile adhesive strength specimens of the polymercement mortar with the powder content1.5%,2.0%and1.5%were prepared andmaintained for28days in standard condition;(2)With the temperature from-18℃to+20℃, the humidity of90%, the flexuralstrength, compressive strength and tensile adhesive strength tests of polymer cementmortar after0,10,20and30times of air freezing and air thawing(for short is air freezingand thawing) and air freezing and water thawing(for short is water freezing and thawing)cycle have been carried out, to obtain the corresponding test data and test curve. (3)Freezing and thawing cycles and powder content effect of polymer cement mortarflexural strength, compressive strength and tensile adhesive strength has been discussed.(4)The damage characteristics of polymer cement mortar under the condition offreezing and thawing environment were analyzed, and the rules of changing on the flexuralstrength, compressive strength and tensile adhesive strength under the condition of freezingand thawing environment were studied.In this paper, technical parameters for the quality and safety of external thermalinsulation composite systems, and for application of corresponding technology in cold area,were provided.