纤维增强富浆胶凝砂砾石的性能研究

Study on performance of rich-mix cemented sand,gravel and rock reinforced by fiber

本文首次研究了纤维对富浆胶凝砂砾石性能的作用,分析了6种不同纤维对富浆胶凝砂砾石坍落度、抗压强度、劈裂抗拉强度、抗冻性的影响,讨论了振捣时间对富浆胶凝砂砾石抗冻性的影响,并结合实际工程,给出了富浆胶凝砂砾石推荐配合比。结果表明,随着单丝聚丙烯纤维掺量的增加,富浆胶凝砂砾石的坍落度逐渐减小,抗压强度和劈裂抗拉强度先增大后减小;聚丙烯纤维和钢纤维对富浆胶凝砂砾石的增强效果最好,且掺入1. 2 kg/m^3聚丙烯纤维、钢纤维的富浆胶凝砂砾石抗冻性分别可达400次、300次;为保障纤维提高富浆胶凝砂砾石抗冻性的效果,掺入纤维的富浆胶凝砂砾石振捣时间不宜长于45 s;给出了岷江航电犍为防护堤垫层及防渗保护层富浆胶凝砂砾石的推荐配合比,掺入聚丙烯纤维后,可减小水泥用量。

In this paper,the effect of fiber on the properties of rich-mix cemented sand,gravel and rock(RMCSGR)is studied for the first time,and the influence of six different fiber on the performance of RMCSGR,including slump,compressive strength,splitting tensile strength,and frost resistance,is studied.In addition,the influence of vibrating time on frost resistance of RMCSGR is discussed herein,and a proportion of RMCSGR is recommended based on a practical engineering project.The results show that the slump of RMCSGR decreased gradually with the increase of the content of monofilament polypropylene fiber,and the compressive strength as well as splitting tensile strength first increased and then decreased.Polypropylene fiber and steel fiber has the best enhancement effect on RMCSGR.Moreover,the freeze-thaw resistance of rich-mix cemented sand,gravel and rock with1.2kg/m^3polypropylene fiber and steel fiber can reach400times and300times,respectively.To ensure the effect of fiber on improving frost resistance of RMCSGR,the vibrating time of RMCSGR mixed with fiber should not be longer than45s.The recommended mix ratio of RMCSGR for embankment cushion and impermeable protective layer of Minjiang Hangdian Qianwei dyke is given,and the amount of cement can be reduced after adding polypropylene fiber.