基于定量机电阻抗方法的混凝土固化过程模量和内耗测量监测

Monitoring of curing process of concrete based on modulus and internal friction measurement using a quantitative electromechanical impedance method

测定新鲜混凝土凝固状态对于控制建筑质量和安全至关重要.实际上,混凝土通常需要约28天时间进行养护,期间混凝土凝固并加强,直至达到可使用标准.传统的混凝土养护过程通常使用超声波等方法测量杨氏模量.在这项工作中,我们提出了一种基于定量机电阻抗方法(Q-EMI)精确测量模量和内耗的实时混凝土养护监测方法.结果表明,模量和内耗均可用于监测混凝土养护过程,且模量测量更准确,因其受支撑条件影响较小.对于特定的混凝土,杨氏模量在4天后趋于稳定,剪切模量在7天后才能稳定,因此剪切模量测量更适合用于监测混凝土养护过程.此外,还发现养护时间对砂/水泥比非常敏感.这项工作为使用小样本监测混凝土养护过程提供了一种便捷方法.

The determination of the condensation state of fresh concrete plays a crucial role in controlling the quality and safety of construction.In practice,it usually takes about 28 days for concrete to cure,during which the concrete mixture is hardened and strengthened until it reaches the usable standards.The traditional methods for monitoring the curing process of concrete usually only measure the Young’s modulus using the ultrasonic method.In this work,we propose a real-time concrete curing monitoring method based on accurate measurement of modulus and internal friction using a quantitative electromechanical impedance method(Q-EMI).Results show that both the modulus and internal friction can be used to monitor the curing process of concrete,and the modulus measurement is more accurate as it is less influenced by supporting conditions.For a specific concrete,the Young’s modulus turns to be stable after 4 days and the shear modulus cannot be stable until 7 days later,thus shear modulus measurement is more suitable for monitoring the curing process of concrete.In addition,it is found that the curing time is quite sensitive to the sand/cement ratio.This work provides a convenient approach to monitoring the curing process of concrete using small samples.