Abstract:Six mixtures were designed on fly ash based geopolymeric recycled concrete (GRC)

which using recycled coarse aggregates (RA) to substitute nature coarse aggregates (NA) with different ratios of 0%，50% and 100%．According to the present code on ordinary concrete(GB/T 50082-50082)and taking into account the characteristics of the geopolymer concrete

multiple comparative analysis were conducted by measuring the compressive strength

weight and dynamic elastic modulus of specimens at different cycles. Furthermore

the microstructure of the specimens attacked by sulphates was also investigated. The performances of sulphates attack resistance and the damage mechanism and of GRC and recycled aggregates concrete (RAC) in the same erosion condition are analyzed and discussed. Results turned out that the maximum weight variation of both RAC and GRC were small in the whole process

that is

1.8% for RAC and 0.7% for GRC. The compressive strength of RAC varies in similar way

and the RAC50 performs the best corrosion resistance judged by corrosion resistance coefficient. The compressive strength of GRCs decreased with more recycled aggregates. The corrosion resistance coefficient shows that erosion process accelerated the strength development of GRC. Dynamic elastic modulus reflect the strength change mechanism of both RAC and GRC. Furthermore

microscopic and chemical analysis shows that the pore structure of RAC takes the most important role in in sulfate attack resistance while

GRC depends on the intrinsic defects of recycled aggregates.