Abstract: With the aid of Scanning Electron Microscope ( SEM ) and Mercury Intrusion Porosimetry ( MIP) , the influence of BSF composite mineral admixture on the mechanical properties of pavement concrete was investigated .The results show that ( 1 ) Involving BSF composite mineral admixture could enhance the flexural strength of concrete after curing for 28 d, decrease the ratio of compress strength to flexural strength significantly , as well as, improve the brittleness of concrete .( 2 ) The use of BSF composite mineral admixture was helpful for improving the microstructure of interface transition zone by densified microstructure and reduced harmful micropores . ( 3 ) During hydration , the brick and granulated blast furnace slag powder used to prepare BSF admixture could generate massive fibrous micro crystal , which is good for improving the flexural strength of concrete .

Key words: concrete pavement;BSF composite mineral admixture;flexural strength