| Fair-faced concrete has been eroded by the natural environment for a long time,and its service life has been greatly affected.Prolonging the service life of clear-faced concrete has become an important issue that needs to be solved at present.Previous studies on the durability of fresh concrete generally focused on adding additives or changing the mix ratio.This method can only be applied to the proposed fresh concrete project.By coating the surface of the fresh concrete with a protective agent,the durability and decorative effect of the fresh concrete can also be improved.This method can be used not only in the proposed fresh concrete project,but also in the existing concrete project.The scope is wider.At present,among the many clear concrete protective agents,acrylic is the lowest in cost and has an economic advantage in the market,but its comprehensive performance is relatively weak,which limits its development in high-quality high-standard clear concrete projects.In order to solve this shortcoming,this article modified the silicon-acrylic protective agent through nano-materials to achieve the purpose of improving the performance of the protective agent.In order to control the economic cost,the content of the silicone-acrylic emulsion closest to the purpose of modification is obtained in this paper.The silicone-acrylic emulsion is divided into five gradients of 30%,35%,40%,45%,and 55%.A performance test study was conducted.The results showed that when the content of the silicone-acrylic emulsion was40%,in addition to the stain resistance of the protective agent not meeting the standards,its adhesion,alkali resistance,scrub resistance,and water resistance meet the General technical requirements for building exterior exterior wall coating system;then the experimental research on the effect of titanium dioxide content on the stain resistance and hiding power of the protective agent,the research results show that as the titanium dioxide content increases,the hiding power and stain resistance of the protective agent are improved,but When the mass fraction is above 25%,the hiding power of the protective agent does not change much.Then the experimental research on the effect of the amount of nano-Si O2/nano-CaCO3 composite slurry on the performance of the silicon-acrylic protective agent was carried out.The research results show that:nano-SiO2/nano-CaCO3 composite slurry is between 6%and 8%,and the performance of the silicone-acrylic protective agent is the best.Among them,the washing resistance can reach 64394 times,and the stain resistance and reflection reduction rate is 4%,which is much better than the General technical requirements for building exterior exterior wall coating system;Finally,according to the common quality problems of protective agents,a supporting construction quality control requirement was proposed. |
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