聚丙烯纤维混凝土早期塑性开裂特征及分形评价

目的研究了聚丙烯纤维对混凝土塑性开裂特征的影响,为改善混凝土塑性开裂提供理论依据.方法采用平板约束法,研究不同掺量、不同长度的聚丙烯纤维对混凝土塑性开裂特征的影响,并应用分形理论,计算了聚丙烯纤维混凝土塑性开裂的分形维数.结果聚丙烯纤维的掺入阻碍了裂缝的产生和发展,且随着体积掺量的增加、长度的增长阻裂效果增强;裂缝分形维数的发展随着纤维掺量的增加、长度的增长而减缓,裂缝复杂化程度减缓.结论聚丙烯纤维能有效地延缓裂缝的产生和发展;应用分形理论分析评价混凝土早期塑性开裂特征是十分有效的.

The character of early-age plastic cracking of polypropylene fiber reinforced concrete and Fractal Evaluation

Aimed at the increasingly serious phenomenon of concrete cracking at the early age,this paper studies the effect of polypropylene fiber on the plastic shrinkage cracking of concrete,providing theoretical foundation for improving the plastic shrinkage cracking of concrete.Experimental research is conducted to study the effect of fiber length and volume fraction on concrete plastic cracking by flat plate method.The fractal dimensions of the plastic shrinkage cracking of polypropylene fiber reinforced concrete are calculated based on the fractal theory.The formation and development of the cracks can be slowed by adding polypropylene fibers(PPF) into concrete.The crack resistant property increases while the fractal dimensions and complexity of cracks decrease accompanied with the increasing dosage and length of PPF.The results show that PPF can be effectively slowed the formation and development of the cracks,and it is effective to evaluate the early-age plastic shrinkage cracking of concrete by applying the fractal theory.