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考虑钢纤维和聚丙烯纤维的体积率、长径比等因素的影响,设计制作36个钢-聚丙烯混杂纤维混凝土试件,通过中心拉拔试验,研究低周反复荷载作用下钢-聚丙烯混杂纤维混凝土与变形钢筋间的黏结强度。结果表明:混杂纤维的掺入对混凝土与钢筋间的黏结强度存在正混杂效应,其中钢纤维对黏结强度的提高作用更为明显。对于混杂纤维混凝土,在聚丙烯纤维体积率为0.15%、长径比为167的情况下,当钢纤维体积率从0.5%增长到1.5%、长径比从30增加到80时,黏结强度分别提高了20.57%和14.75%,而聚丙烯纤维体积率和长径比的变化对黏结强度没有明显影响;当混杂掺入体积率为1.5%、长径比为60的钢纤维与体积率为0.15%、长径比为167的聚丙烯纤维时,与相应的单掺钢纤维混凝土、聚丙烯纤维混凝土和普通混凝土相比,黏结强度分别提高了14.64%、31.37%和46.55%。此外,基于厚壁圆筒理论,针对实际受力情况,建立了钢-聚丙烯混杂纤维混凝土与变形钢筋黏结强度的理论模型,计算结果与实测结果吻合良好。
Considering the influence of the volume fraction, the aspect ratio and other factors of steel fiber and polypropylene fiber, 36 steel-polypropylene hybrid fiber concrete specimens were designed and manufactured. The center pull test was carried out to study the influence of steel-polypropylene Bond strength between hybrid fiber concrete and deformed bar. The results show that there is a positive hybrid effect between the hybrid fibers and the bond strength between the concrete and the reinforcing steel, and the reinforcing effect of the steel fiber on the bond strength is more obvious. For the hybrid fiber reinforced concrete, when the volume fraction of polypropylene fiber is 0.15% and the aspect ratio is 167, when the volume fraction of steel fiber increases from 0.5% to 1.5% and the aspect ratio increases from 30 to 80 But the change of volume ratio and aspect ratio of polypropylene fiber had no significant effect on the bond strength. When the mixed volume fraction of fiber was 1.5%, the aspect ratio of steel fiber was 60 and the volume fraction was 0.15 % And L / D ratio of 167, the bond strength increased by 14.64%, 31.37% and 46.55%, respectively, compared with the corresponding single-doped steel fiber reinforced concrete, polypropylene fiber reinforced concrete and ordinary concrete. In addition, based on the theory of thick-walled cylinder, a theoretical model of the bond strength between steel-polypropylene hybrid fiber reinforced concrete and deformed steel bar is established according to the actual stress situation. The calculated results are in good agreement with the measured results.