碳化砂浆轴向冲击动态力学特性与破碎形态分析

Analysis on dynamic mechanical characteristics and fracture morphology of carbonated mortar under axial impact

为保证长期使用砂浆在动载作用下的安全性,采用非金属超声波检测仪测量不同碳化龄期试件的纵波波速,引入碳化增强因子η表征碳化深度大小,并利用直径50 mm变截面分离式Hopkinson压杆试验装置开展不同碳化龄期砂浆冲击动态压缩试验,研究碳化后砂浆的动态力学特性与破碎形态,分析砂浆动态应力—应变曲线、峰值应力和破碎形态随碳化龄期变化规律。结果表明:随着碳化龄期的增长,试件波速呈增大趋势,碳化增强因子η增大,碳化深度增加;碳化龄期相同时,砂浆的动态峰值应力、峰值应变都随着冲击气压的增大而增大;冲击气压相同时,砂浆的动态峰值应力随着碳化龄期的增长而增加;试件的破坏形态主要呈现为压碎破坏与劈裂拉伸。

In order to ensure the safety of the long-term used mortar under the dynamic load,the non-metallic ultrasonic detector was used to measure the longitudinal wave velocity of specimens with different carbonization ages,and the carbonization enhancement factorηwas introduced to reflect the size of carbonization depth,and the variable cross-section split Hopkinson pressure bar(SHPB)test device with the diameter of 50 mm was used to carry out the impact dynamic compression tests on the mortar with different carbonation ages.The dynamic mechanical properties and fracture morphology of mortar after carbonation were studied,and the change laws of dynamic stress-strain curve,peak stress and fracture morphology of mortar with the carbonation age were analyzed.The results showed that with the increase of carbonation age,the wave velocity of specimens increased,the carbonation enhancement factorηincreased,and the carbonation depth increased.When the carbonation age was the same,both the dynamic peak stress and strain of mortar increased with the increase of impact air pressure.When the impact air pressure was the same,the dynamic peak stress of mortar increased with the increase of carbonation age.The failure morphology of specimens mainly presented as the crushing failure and splitting tension.