Development of real-time visual monitoring system for vibration effects on fresh concrete

Abstract The consolidation of concrete is crucial to ensure the long-term strength and durability of concrete structures. Although fresh concrete can be consolidated properly via vibration, the consolidation quality heavily relies on construction workers' experience. Inexperienced workers tend to under-consolidate or over-consolidate concrete, resulting in indiscoverable and irreparable defects. It is necessary to establish a system that can track the real-time vibration activity and feedback vibration defects to the inspector and worker. In this paper, a real-time visual monitoring system of the vibration effects is developed and validated to solve the under-vibration issues of fresh concrete. The vibration trajectory is accurately tracked by Global Navigation Satellite System (GNSS). The vibration duration is calculated based on the alternation time of vibration status. The data is transmitted and stored in a cloud server by General Packet Radio Service (GPRS). The radius of action and effective vibration zone are determined by experiments and geometric models. The vibration effects are visualized in three dimensional at the control site. A mobile App is also developed to visualize defects to the inspector such that re-vibration can be timely conducted. Field experiments demonstrate that the tracking accuracy of the system satisfies the demand of construction applications. Through comparing the defect report of the system to the results of the nondestructive impact-echo method in a construction case study, the reliability of the system is verified.