钢纤维混凝土抗冲击性能及其阻裂增韧机理

发布时间：2019-05-28 08:19

【摘要】：采用自制落锤冲击试验装置,以韧性系数和延性比来评价钢纤维混凝土(SFRC)的韧性,研究了钢纤维对混凝土抗冲击性能的影响.以纤维分散系数表征钢纤维分布的均匀程度,对冲击面裂缝进行观测,并对冲击断面纤维分布进行了统计计算,分析了冲击荷载作用下钢纤维混凝土的阻裂效应及增韧机理.结果表明:钢纤维的掺入可显著提高混凝土的抗冲击性能;在钢纤维掺量(体积分数,下同)为0.8%时,钢纤维混凝土的延性比超过15%,其韧性系数随钢纤维掺量的提高而增大,在钢纤维掺量为1.0%时达到最大值,接近基准混凝土的10倍;钢纤维的掺入降低了基体脆性,改善了其塑性特征,从而延缓了钢纤维混凝土的裂缝开展,并改善了其主裂缝形状、减少了裂缝条数;钢纤维混凝土的抗冲击韧性与钢纤维掺量及其在冲击断面上的分布均匀程度密切相关.
[Abstract]:The toughness of steel fiber reinforced concrete (SFRC) was evaluated by toughness coefficient and toughness ratio by using a self-made drop hammer impact test device, and the effect of steel fiber on the impact resistance of concrete was studied. The uniformity of steel fiber distribution was characterized by fiber dispersion coefficient. The crack distribution on impact surface was observed, and the fiber distribution on impact section was statistically calculated. The crack resistance effect and toughness mechanism of steel fiber reinforced concrete under impact load were analyzed. The results show that the impact resistance of concrete can be significantly improved by adding steel fiber. When the content of steel fiber (volume fraction, the same below) is 0.8%, the ductile ratio of steel fiber concrete is more than 15%, and the toughness coefficient increases with the increase of steel fiber content, and reaches the maximum when the content of steel fiber is 1.0%. 10 times as close to the reference concrete; The addition of steel fiber reduces the matrix brittleness and improves its plastic characteristics, thus delaying the crack development of steel fiber reinforced concrete, improving the shape of its main crack and reducing the number of cracks. The impact toughness of steel fiber reinforced concrete is closely related to the content of steel fiber and the uniform distribution of steel fiber on the impact section.
【作者单位】：燕山大学河北省重型装备与大型结构力学可靠性重点实验室;
【基金】：国家自然科学基金资助项目(51608469,51578477) 河北省研究生创新能力培养资助项目(CXZZSS2017054)
【分类号】：TU528.572

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