In order to study the effect of freeze-thaw cycle on the dynamic mechanical properties of straw fiber concrete with different fiber content.The longitudinal wave velocity of straw fiber reinforced concrete specimens under different freeze-thaw cycles is measured by non-metallic ultrasonic detector.The dynamic uniaxial compression test of the specimen was carried out by using the variable cross-section split Hopkinson compression bar test device with a diameter of 74 mm.The relationships between the longitudinal wave velocity,peak stress,deterioration degree,toughness and crushing energy consumption density of the specimen and the times of freeze-thaw cycles and the content of straw fiber were analyzed.The results show that the addition of fiber can improve the longitudinal wave velocity and integrity of concrete materials.With the increase of freeze-thaw cycles,the longitudinal wave velocity of straw fiber concrete decreases,and the freeze-thaw cycles will cause damage to the specimens.The addition of straw fiber will enhance the mechanical properties of concrete materials,and the effect is the best when the content is 0.2%.The peak stress of the specimen under freeze-thaw cycle is decreasing and the deterioration degree is increasing.Compared with the plain concrete specimen under freeze-thaw cycle 0,the peak stress of the specimen under freeze-thaw cycle 30,60,90 and 120 times is reduced by 6.96%,19.4%,34.2%and 53.3%respectively.The stress decline increases significantly in the later stage of freeze-thaw cycle,and the addition of fiber slows down the deterioration degree of the specimen under freeze-thaw to a certain extent.When the fiber content is 0.2%,the toughness and crushing energy consumption density of the specimen increase the most.The freeze-thaw cycle will degrade the specimen and reduce its toughness and energy absorption effect.However,the incorporation of straw fiber greatly increases the mechanical properties of concrete materials.The green renewable nature of straw fiber is of great significance to the promotion of straw fiber concrete.
freeze thaw cyclestraw fiberlongitudinal wave velocitypeak stressdegree of deteriorationtoughnesscrushing energy consumption density
维普
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