中文摘要：

摘要：为了解新型粗合成纤维对改善混凝土抗弯韧性的效果，试验研究了纤维掺量、基体强度、纤维直径等因素对混凝土抗弯韧性的影响规律。结果表明：单掺或混掺不同几何尺寸粗合成纤维后，试件具有很好的韧性，呈延性破坏；抗弯韧性指数随纤维掺量的增加而增大；基体强度提高时，抗弯韧性指数略有上升；纤维直径不同时，抗弯韧性指数变化不明显；3种合成纤维与钢纤维混掺后，其抗弯韧性指标大于单掺钢纤维或3种合成纤维混掺的试件；混掺粗合成纤维可有效改善梁裂后行为，即峰值荷载后仍保持较高荷载；而单掺钢纤维梁在峰值荷载后，荷载下降较快；新的抗弯韧性评价方法能够准确地反映粗合成纤维混凝土裂后阻裂能力高、变形大的特点。

英文摘要：

In order to grip the flexural toughness impact of new type synthetic macro-fiber on reinforced concrete, the effects of the fiber content, the matrix strength of reinforced concrete and the diameter of fiber on the flexural toughness were studied. The results show that the addition of synthetic macro-fiber changes the failure mode of reinforced concrete from brittleness to ductility. The flexural toughness index increases with the fiber content, it also increases when the matrix strength increases~ and it has＇t evidently changed when the diameter of fiber changes. The flexural toughness of reinforced concrete with steel fiber and three synthetic macro-fiber is higher than those of steel fiber or three synthetic macro-fiber, and synthetic macro-fiber can increase the toughness of reinforced concrete. The synthetic macro-fiber reinforced concrete can have a higher load after the peak load, but the load of concrete with steel fiber decreases quickly after the peak load, the characteristic of reinforced concrete with synthetic macro-fiber can be proved by the new toughness evaluation method.