| As a new environmental protection material, Wood-plastic Composites meet the needs of the national energy saving requirements, and incarnate a certain advantage. This essay adopts wood-plastic composites as the building envelope and refers to the design ideas of light steel structure building and light timber structure building to build an undetachable WPC prefabricated house with steel structure as a whole, which is a new breakthrough and exploration in the engineering application of wood-plastic composites.This essay focuses on the overall evaluation of the general function of the WPC prefabricated house, including the following parameters: the basic performance of WPC siding, the distribution characteristics of surface temperature on the interior and exterior wall of the WPC prefabricated house, interior temperature and relative humidity of the WPC prefabricated house, the durability under the exterior natural environment as well as the thermodynamic disfigurement. It is hoped that this systematic study will help wood-plastic composites attract builders and expand its application in building materials.According to the tests, the conclusions are reached as follows:1) It is feasible to adopt WPC siding as the building envelope.2) The WPC prefabricated house had unsatisfactory thermal stability and was easily subject to the solar radiation. The surface temperature of the external wall became moderate when it reached the internal wall via the compound heat reservation wall with 5 layers, which lead to the decrease and delay of the surface temperature. However, the delay time was short and the effect of heat insulation was insufficient.3) Compared with the loess cave dwellings and the traditional rammed earth dwellings, the stability of interior temperature was poor. The maximum and minimum relative humidity were far beyond and below the value fitted for man(40%～60%), separately. Closed and ventilated room in the sunny day demonstrated a periodic (24h) undulatory property. The wave crest of the temperature curve almost corresponded to the wave trough of the relative humidity curve and vice versa. The temperature curve and the relative humidity curve in the rainy day did not display obvious wave crests and troughs and the fluctuation was moderate. The delay time of internal and external temperature was short, similar to that of surface temperature of internal and external wall.4) Through 8 months of natural climate ageing test, both the bending strength and the bending elastic modulus of the rice husk/PE composites with surface grinded and without surface grinded shew different degrees of decrease. Within the 8 months, the WPC prefabricated house experienced color fading with green lightening and blue deepening, and the fading beyond recognization. Therefore, anti-UV absorbents, antioxidants and pigments should be added into the formulation to assure the appearance of this material.5) According to infrared thermograms, it was found that the junction between the roof and the upper wall, the joint between the steel structure and the adiabator and the crack between the adiabator were places where heat easily passed and lost, which was caused by installation of this WPC prefabricated house. But the critical problem was the absence of some adiabator. In the future design, the conjunction should be given much consideration to prevent the loss of heat and leak of water.In general, further design and improvement are needed if this WPC prefabricated house achieves promotion and generalization.
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