关键词: 直接拔出试验;粉煤灰混凝土;冻融循环;粘结强度;韧性

Abstract: Through the direct pull-out test of the fly ash concrete specimens,it was analyzed for change rule of fly ash and freeze-thaw on initial bond strength,bond slip the splitting strength,ultimate bond strength and the toughness evaluation index which expressed as an area under the bond strength slip curve. The results of pull-out test with different fly ash dosage and freeze-thaw cycle number show that the bonding strength between steel bar and concrete decreases as the content of fly ash increasing;bond toughness decreases and then increases with the increasing of fly ash dosage,large dosage of fly ash specimen showes good toughness in the loading process;the influence of freeze-thaw action on ultimate bond strength decreases with increasing of fly ash,40% fly ash dosage specimen under freeze-thaw environment showes good toughness. The addition of much fly ash can slow down the freeze-thaw damage of bonded specimens to some extent.

Key words: pull-out test;fly ash concrete;freeze-thaw cycle;bonding strength;toughness