Study On Modification And Application In Concrete Of Polyaspartic Acid

This paper was mainly to solve the issues of polyaspartic acid(PASP) about the strong retarding effect and low water-reducting rate,through modifying the structure of PASP and respectively connecting to different groups in branched chain,in order to increase the early strength of concrete and water-reducting rate.at the same time,modificated PASP kept the original small clay sensitivity and slump.both in China and abroad,studies of the PASP and the modified PASP mainly concentrated on medical,sewage processing,agricultural and fertilizer etc,but it have not seen the related literature in the application of cement and concrete.Therefore,it was a very high innovation and independence that modified PASP were applied to cement and concrete.The test used four kinds of organics(A、B、C and D)in three different molecular weight PASP,to introduce A、B and C in the chain.At the same time,it also increased the molecular weight of branched chain.Accord to controlling Temperaturetime,molar and other factors,it was determined that the best synthetic scheme of modified PASP.The paper selected three kinds of modified PASP,such as AS,AY and BS,because it had a better water-reducing effect than PASP,and applied it to cement paste and concrete, determinated the following contents : the fluidity and water-reducing of Pastes,the slump of concrete and by the time of loss,he strength of concrete at the different age,clay sensitivity,durability etc.After analyzed the performance of the modified PASP.The paper also analyzed modified PASP taking advantage of Fourier transform infrared analyzer,eight-channel micro-calorimeter,zeta potential instrument.By infrared analyzer,it was proved that ethanolamine and taurine could be grafted successfully; taking advantage of the eight-channel micro-calorimeter, it was confirmed that the modified PASP had early rapid-hydration of cement;By zeta potential analyzer,Analying of water-reducing mechanism whose PASP and modified PASP.The results of test indicated that the three modified PASP improved strongly retarding effect and improved the water-reducing admixture rate,and kept the original small clay sensitivity and good slump.