Li Guodong, Zhang Li, Zhao Fengnian, Tang Jiaqi
Transportation Institute, Inner Mongolia University, Hohhot 010070, China.
Inner Mongolia Engineering Research Center of Testing and Strengthening for Bridges, Hohhot 010070, China.
Materials (Basel). 2020 Sep 10;13(18):4009. doi: 10.3390/ma13184009.
This paper presents the compression failure process of basalt fiber concrete with recycled aggregate and analyzes the main factors of basalt fiber and recycled aggregate affecting the compressive strength of recycled concrete. The damage mechanism of recycled aggregate concrete is analyzed by the acoustic emission technique. With the method of acoustic emission (AE) b-value analysis, the evolution and failure process of recycled concrete from the initial defect microcrack formation to the macroscopic crack is studied. Based on the AE clustering analysis method, the damage state of recycled concrete under load grade is investigated. Finally, the failure mode of recycled concrete is explored according to the RA-AF correlation method. The results show that when the concrete reaches the curing age, the strength grade of basalt fiber regenerated coarse aggregate concrete is the highest. The basalt fiber increases the strength of regenerated fine concrete by 4.5% and the strength of coarse concrete by 5%, and reduces the strength of fully recycled aggregate concrete by 6.7%. The b-value divides concrete into three stages: initial damage, stable development of internal damage, and internal damage. The variation of AE energy, count, and event number is related to AE activity and crack growth rate. Matrix cracking is the main damage state of concrete, which is greatly affected by the strength of cement mortar. The load grade of fiber cracking in fully recycled aggregate, recycled fine aggregate, and recycled coarse aggregate concrete is 65, 90, and 85%, respectively. Basalt fiber increases the tensile failure event point of recycled concrete and delays the cracking of recycled concrete under compression. When the load grades of fully recycled fiber, recycled fine aggregate fiber, and recycled coarse aggregate fiber concrete are 65-95, 90-100, and 85-100%, respectively, the tensile failure activity increases.
本文介绍了再生骨料玄武岩纤维混凝土的受压破坏过程，分析了玄武岩纤维和再生骨料影响再生混凝土抗压强度的主要因素。采用声发射技术分析了再生骨料混凝土的损伤机理。运用声发射（AE）b值分析方法，研究了再生混凝土从初始缺陷微裂纹形成到宏观裂纹的演化及破坏过程。基于AE聚类分析方法，研究了再生混凝土在荷载等级作用下的损伤状态。最后，根据RA-AF相关法探究了再生混凝土的破坏模式。结果表明：混凝土达到养护龄期时，玄武岩纤维再生粗骨料混凝土的强度等级最高。玄武岩纤维使再生细混凝土强度提高4.5%，粗混凝土强度提高5%，使全再生骨料混凝土强度降低6.7%。b值将混凝土分为三个阶段：初始损伤、内部损伤稳定发展和内部损伤。AE能量、计数和事件数的变化与AE活动及裂纹扩展速率有关。基体开裂是混凝土的主要损伤状态，受水泥砂浆强度影响较大。全再生骨料、再生细骨料和再生粗骨料混凝土中纤维开裂的荷载等级分别为65%、90%和85%。玄武岩纤维提高了再生混凝土的拉伸破坏事件点，延缓了再生混凝土受压时的开裂。当全再生纤维、再生细骨料纤维和再生粗骨料纤维混凝土的荷载等级分别为65%-95%、90%-100%和85%-100%时，拉伸破坏活动增加。
