凝结硬化期扰动对混凝土受压声发射特性的影响  

Influence of Disturbance During Setting and Hardening Period on Acoustic Emission Characteristics of Concrete under Compression

作　　者：司秀勇[1] 户伟华 潘慧敏[1] SI Xiuyong;HU Weihua;PAN Huimin(Key Laboratory of Green Construction and Intelligent Maintenance for Civil Engineering of Hebei Province,Yanshan University,Qinhuangdao 066004,China)

机构地区：[1]燕山大学,河北省土木工程绿色建造与智能运维重点实验室,秦皇岛066004

出　　处：《硅酸盐通报》2021年第6期2034-2041,共8页Bulletin of the Chinese Ceramic Society

基　　金：国家自然科学基金(51608469,52078450);河北省重点研发计划(19211505D)。

摘　　要：为了解凝结硬化期间的扰动对混凝土损伤的影响,对处于初凝至终凝阶段的混凝土进行了模拟扰动试验,全程采集了受扰混凝土受压破坏过程产生的声发射信号。通过比较不同试件的声发射特征参数,研究了不同受扰龄期的混凝土在单轴受压条件下的声发射特性,并基于水泥混凝土结构形成动力学对受扰混凝土损伤机理进行了分析。结果表明:扰动使混凝土内部产生了不同程度的损伤,其中凝结硬化中期的扰动对混凝土性能影响较大,使混凝土峰值应力降低25.1%,损伤度达到14.2%,临近初凝和终凝的扰动对混凝土影响较小;与基准混凝土相比,受扰试件在加载初期声发射能量释放率较小,声发射活跃区间出现在加载后期。对于凝结硬化中期受扰的混凝土试件,在相对应力水平小于50%时,未采集到明显的声发射信号,此试件其声发射速率参数a值最小,过程参数b值最大。In order to understand the influence of the disturbance during setting and hardening period on concrete damage,the simulated disturbance test was carried out on the concrete in the initial setting stage to the final setting stage,and the acoustic emission signals generated during the compression failure process of the disturbed concrete were collected.By comparing the acoustic emission characteristic parameters of different specimens,the acoustic emission characteristics of concrete with different disturbed ages under the uniaxial compression were studied.Based on the formation dynamics of cement concrete structure,the damage mechanism of disturbed concrete was analyzed.The results show that the disturbance causes damage to concrete in different degrees.The disturbance in the middle stage of setting and hardening has a great influence on the performance of concrete,which reduces the peak stress of concrete by 25.1%,and the damage degree reaches 14.2%.The disturbance near initial setting and final setting has little effect on concrete.Compared with the reference concrete,the acoustic emission energy release rate of the disturbed specimen is smaller at the initial stage of loading,and the active range of acoustic emission appears in the later stage of loading.When the relative stress level is less than 50%,there is no obvious emission signal.The acoustic emission rate parameter a is the smallest and the process parameter b is the largest.

关 键 词：混凝土 凝结硬化期 扰动 声发射 损伤 

分 类 号：TU528[建筑科学—建筑技术科学]