基于声发射技术的早龄期扰动对混凝土力学性能影响分析

为研究早龄期扰动对混凝土力学性能的影响并明确其影响机理,采用室内扰动的方法在混凝土凝结初期和凝结中期提供扰动并进行强度试验和声发射试验,从微观角度分析早龄期扰动对混凝土力学性能的影响。结果表明,早龄期扰动对混凝土力学性能影响较大,凝结初期受扰动混凝土抗压强度增大,凝结中期受扰动混凝土抗压强度减小,同时不同扰动参数变化对试件抗压强度影响不同。根据不同声发射参数分析,发现早龄期扰动后试件初始微裂纹数量越少,损伤越小,试件破坏时累积能量越大,产生剪切裂缝事件点所占比率越小。最后,从初始微裂纹角度解释了早龄期扰动对混凝土力学性能的损伤机理。

Influence of Early Age Disturbance on Mechanical Properties of Concrete Based on Acoustic Emission Technology

In order to study the influence of early age disturbance on the mechanical properties of concrete and clarify its influence mechanism,the strength test and acoustic emission test were carried out in the initial and middle stages of condensation by means of indoor disturbance. The influence of early age disturbance on the mechanical properties of concrete was analyzed from the mesoscopic view. The results show that the early age disturbance has a great influence on the mechanical properties of concrete. The compressive strength of disturbed concrete increases in the initial stage of condensation, and decreases in the middle stage of condensation. Meanwhile, the influences of different disturbance parameters on the compressive strength of specimens are different. According to the analysis of different acoustic emission parameters, it is found that the smaller the number of initial microcracks is, the smaller the damage is and the greater the cumulative energy is when the specimen is destroyed, and the smaller the proportion of shear crack events is. The damage mechanism of early age disturbance on mechanical properties of concrete is explained from the perspective of initial microcracks.