Gradient Functional Design And Effect Evaluation Of Self-cleaning Resin Translucent Cement Board

Translucent cement-based materials are new building materials with transparent properties,which are composed of translucent components and cement matrix.They are widely used in architectural design,underground lighting,indoor decoration and other fields.After long-term of direct contact with haze,acid rain,dust and other pollutants during the use of translucent cement-based materials,a layer of pollutants composed of rainwater,dust and other pollutants will adhere to the surface,especially the surface of translucent components.This will lead to a significant decline in the transparency,daylighting performance and energy-saving effect of transparent cement-based materials.The research work in this paper comes from the project Interface characterization of resin light conductive cementitious materials and its deterioration mechanism in simulated service environment（Grant No.51562024）of Chinese National Natural Science Foundation and the project Basic Research of Environmental Friendly Resin Light Conductive Cement-based Materials（Grant No.20162BCB23014）of Jiangxi Outstanding Young Talents Subsidy Scheme.In this paper,the gradient function design idea was introduced to design a Self-cleaning Resin Translucent Cement Board（SRTCB）with functions of transparent development,energy saving and hydrophobic self-cleaning.Translucent resin and cement matrix was used as carriers to study the hydrophobic and self-cleaning properties of self-cleaning coatings by observing the hydrophobic angle and attachment morphology of water droplets and the mechanism of self-cleaning coatings by ESEM.SRTCB was used as carrier to study daylighting and energy saving characteristics by Autodesk Ecotect Analysis and visual effect simulation by Radiance and the hydrophobic self-cleaning effect by droplet attachment morphology and droplet rolling test.The effect evaluation system of SRTCB was established.The main work and achievements are as follows:1.The gradient function design idea was introduced to realize the function/structure integrated design of SRTCB through function design,material optimization and structure design.SRTCB is an advanced building material with self-compacting cement mortar as cement matrix,translucent resin as translucent component,coupling agent as interface reinforcement component and hydrophobic coating as self-cleaning component.SRTCB has the functions of transparent development,energy saving and hydrophobic self-cleaning.2.SRTCB is prepared by prefabricated pre-implantation method,which includes prefabricated transparent resin unit,brushing interface enhancement,implantation of cement matrix and spraying coating.3.SS-02 and NC319 hydrophobic coating used on translucent resin and cement matrix have good self-cleaning effect.Water droplets are aggregated on the surface of translucent resin and cement matrix which were treated by SS-02 and NC319.After spraying SS-02 hydrophobic layer,the hydrophobic angle of translucent resin surface and cement mortar surface reached 114.6°and 104.4°respectively,which met the angle of hydrophobic requirements.After spraying NC319 hydrophobic layer,the hydrophobic angle of translucent resin surface and cement mortar surface reached 156.2°and 152.4°respectively,which met the angle of superhydrophobic requirements.Water droplets can slide freely on SS-02 and NC319 hydrophobic coatings without any residual water.4.The main components of SS-02 and NC319 hydrophobic coating are modified nano-Si O₂.The hydrophobic principle of SS-02 is that the modified nano-Si O₂ particles has characteristic of low surface energy.The surface roughness will increase the hydrophobicity at low surface energy.Although SS-02 hydrophobic coating has been modified with low surface energy,it does not use Si O₂ nanoparticles to construct nano-scale surface roughness,so it can only achieve hydrophobic effect.NC319 hydrophobic coating is fabricated with nano-scale roughness on the basis of SS-02 hydrophobic coating and became superhydrophobic structure similar to lotus leaf surface.5.The results of comparison between SS-02 and NC319 hydrophobic coating show that NC319 hydrophobic coating can achieve superhydrophobic effect,SS-02hydrophobic coatings can only achieve hydrophobic effect,but SS-02 hydrophobic coatings have better wear resistance and lower price.The choice of two hydrophobic coating can take into account the requirements of transmittance,durability and economy in practical application.NC319 hydrophobic coating can be selected under low wear resistance environment to provide better superhydrophobic self-cleaning effect.SS-02 hydrophobic coatings can be selected under high wear resistance environment.6.The Autodesk Ecotect Analysis simulation results show that,When the SRTCP is used as a external wall,the average daylighting factor of the room increased by5.78%,the uniformity of daylighting increased by 0.10,the average illumination of the room increased by 518.07 lx,the annual energy saving is 15.25 k W·h.When the RTCP is used as a indoor partition,the dark corner after the partition has been eliminated,the average daylighting factor in the room has increased by 3.99%,the uniformity of daylighting increased by 0.13,the average illuminance increased by377.00 lx,the annual energy saving is 32.06 k W·h.7.Radiance simulation results show that SRTCB can not only meets the requirements of daylighting and energy saving,transparent development and improving the uniformity of indoor daylighting,but also meets the requirements of architectural aesthetics.As building envelope materials and home decoration materials,SRTCB can meet the requirements of architectural aesthetics.8.Droplet attachment morphology and rolling test show that SRTCB can play a significant hydrophobic and self-cleaning effect.The pollutants adhering to SRTCB will fall off with the erosion of rainwater,and keep the transparency and cleanliness of the board.9.The evaluation system of SRTCB effect is established from three aspects:translucent development effect,daylighting and energy-saving effect and hydrophobic self-cleaning effect.Daylighting and energy-saving effect of SRTCB are quantitatively analyzed.