The Influence Of Concrete Admixture On Surface Finish Of Fair-Faced Concrete

With the advance of science and technology,and with the improvement of human's environmental and aesthetic idea transformation,ordinary concrete is difficult to achieve in construction and aesthetic with human's requirements.As a result,a new concrete that is water concrete which is a pouring molding and do not make any foreign modification has come to the world.As the surface of the concrete is not modified by foreign objects,so it's high finish demands on concrete surface.However,the surface of water concrete may comes out some bad phenomenon with mezzanine,pits,voids,porosity etc.because of the raw materials,construction technology and other factors in construction process.These defects may cause the big influence with the surface finish and use effect of water concrete.Therefore,how to solve the concrete surface quality problems is a hot spot of discuss with the construction industry.So,I could study it from the perspective of chemistry on the basis of predecessors' sstuty,that is,through adjust the mixed concrete admixture to improve the surface finish of concrete.This paper conducted the following research:(1)First of all,this paper examines the effect of concrete mix on the performance of concrete.It is adjusted by the concrete mixing experiment on the basis of the concrete mix ratio of the laboratory.Finally,the conclusion is drawn from the experiment data: the sand rate,water-cement ratio,unit volume of water were 41%,0.45,175kg/m~3 are the best condition for mixing concrete.(2)The effect of concrete admixture on the working performance of concrete was investigated under the optimum mix ratio of concrete.Through the analysis of concrete mixing we can known: the best varieties is A2,dosage is 1.45 % of concrete poly carboxylic water reducing agent for concrete mixing.The best air-entraining agent,defoaming agent varieties of B2,C1,dosage of 0.1‰,0.06‰ respectively in admixture compound.(3)Drafting of admixture compound solution and mixing the concrete.The surface of the concrete was observed and evaluated by Image pro plus analysis software.Finally,the admixture had a great influence on the surface finish of the concrete.When the polycarboxylate water reducing agent,air-entraining agent,defoamer content of 1.45%,0.1‰,0.06‰ and 1.45%?0.5‰? 0.3‰,the concrete to obtain the best surface finish.