Mechanics Behavior of Ultra High Toughness Cementitious Composites after Freezing and Thawing

Mechanical behaviors of UHTCC after freezing and thawing were investigated,and compared with those of steel fiber reinforced concrete(SFRC),air-entrained concrete(AEC) and ordinary concrete(OC).Four point bending tests had been applied after different freezing-thawing cycles(0,50,100,150,200 and 300 cycles,respectively).The results showed that residual flexural strength of UHTCC after 300 freezing-thawing cycles was 10.62 MPa(70% of no freezing thawing ones),while 1.58 MPa(17% of no freezing thawing ones) for SFRC.Flexural toughness of UHTCC decreased by 17%,while 70% for SFRC comparatively.It has been demonstrated experimentally that UHTCC without any air-entraining agent could resist freezing-thawing and retain its high toughness characteristic in cold environment.Consequently,UHTCC could be put into practice for new-built or retrofit of infrastructures in cold regions.