Suitable For Rapid Repair Concrete Composite Superfine Powder Admixture Research And Development

With continuous development of economy,greater investment has been put into infrastructure construction and therefore,an important role is played by the contrete in various structural systems.Although there is a certain resistance of contrete structure to be damaged,the safety and durability of its application can be affected seriously by diseases caused by all kinds of factors.As a result,the work of contrete being repaired becomes harder.To alleviate the contradiction between operation and maintenance,to shorten time for maintenance,and meet the requirement of operation as soon as possible,there occurs a strong demand for developing a kind of mixture which can make contrete repaired quickly,with high quality of strength and good durability.It is showed in this paper that a kind of special admixture HPCUP,which can be used to repair contrete quickly and effectively,is developed by adding activator.It can make the early strength be controlled,and at the same time,a simple operation when repairing at the construction site is guaranteed.Firstly,fly ash and slag powder are chosen as basic materials and the admixture ratio optimization test is conducted.The water content,initial and final setting time,comprehensive strength and flexural strength of mortal are determined through orthogonal test,which helps the most effective activator to be selected and the proportion of admixture to be determined.In the final determined experiment approach,the amount range of fly ash,lag powder,activator A and activator B,is respectively 0~5%,5%~10%,20%~30% and 0.8%~1.6%.Through bond strength test and ultrasonic test,it is proved the bond strength and compactness of the rapid repairing material are better than those of ordinary materials.Secondly,the study of rapid repairing contrete with high performance is conducted based on the developed mixture.And compared with ordinary contrete with high performance in comprehensive and flexural strength,durability test and microstructure test,the rapid repairing contrete with high performance has obviousadvantages of strength,compactness and durability,and the controllability of condensation time can be achieved.Finally,repairing work of a bridge on the Beijing-Shanghai expressway has been finished by application of the above studying results.The demand 1d open to traffic can be met by contrete prepared on the spot.And what's more,contradiction between restoration and operation is alleviated,and expected objective is achieved with the contribution of it.