If buildings are the skeleton of a city, then concrete pouring is the blood that gives it life. For a long time, the vibration and curing processes in concrete pouring have been pain points in construction management—the quality of vibration and curing is limited by workers' experience and weather conditions, which not only affects structural safety but also causes a huge waste of human and material resources. How can we solve this problem?

China Construction Third Engineering Bureau Group Co., Ltd. Zhongyuan Branch has successfully developed key technologies for the intelligent control of concrete vibration and curing based on an Internet of Things (IoT) gateway, and has applied them to projects under construction.

This technology is like equipping a traditional construction site with an “intelligent hub”. "Our key innovation lies in the introduction of the IoT gateway. It acts as the general commander on the construction site," said Qian Chuanbin, head of the technical department of Zhongyuan Company. This IoT gateway is an industrial-grade computer that can withstand the harsh environment of the construction site, and builds a collaborative control system according to the four-layer architectural logic of "perception-network-platform-application". This architecture allows the control loop reaction time of concrete construction to leap from "seconds" to "milliseconds", achieving true "instantaneous in-process correction".

The vibrator is a key tool to ensure concrete compactness, but in the past, whether it was vibrated, for how long, and how well it was vibrated depended entirely on the workers' feel. “We made a modification to ordinary vibrators and installed an RTK high-precision positioning module,” introduced Li Dajiong, Chief Engineer of Zhongyuan Branch. “In this way, every position where the vibrator is inserted into the concrete can be accurately recorded, forming a high-definition motion trajectory. Subsequently, by comparing it with the pre-divided BIM model grid, it is clear at a glance which areas are within the grid (already vibrated) and which are not (missed vibration), completely bidding farewell to the era of blind vibration based on feeling.”

Just knowing the location is not enough; the vibration quality must also be judged. To this end, Zhongyuan Branch’s technical team integrated a "dual-insurance stethoscope" into the vibrator: a three-axis vibration sensor monitors external vibration status, and a current sensor monitors internal motor load. Whether the concrete is vibrated densely is directly reflected in the vibration frequency spectrum and current curve. Through algorithmic analysis, the monitoring system can accurately determine whether it is “under-vibrated”, “over-vibrated”, or perfectly “dense”, and instantly issues audio-visual alarms through the gateway to guide workers in adjusting their operations.

In terms of concrete curing, the intelligent temperature and humidity curing device developed by Zhongyuan Branch is like a personal AI nanny. This device integrates environmental temperature and humidity sensors, can perceive weather changes in real-time, and transmits the data to the IoT gateway in real-time. The built-in intelligent algorithm will automatically calculate and make dynamic decisions based on different temperature and humidity changes. The entire process requires no manual intervention, and the status can be remotely viewed and manually adjusted via a mobile App. “In areas that underwent intelligent curing, the curing is uniform with no dead corners, the total number of cracks is reduced by 69%, and the water-saving rate reaches 39%," said Zhang Tao, then project commander of the CCTEB Shanghai Longhua Hospital Henan Hospital project.

Today, this innovative achievement has been evaluated by experts as reaching an internationally advanced level. “In the future, this ‘intelligent hub’ is expected to manage more equipment and processes on the construction site, deeply integrate with technologies such as AI and digital twins, and promote the construction industry to firmly advance on the path of high-quality digital and intelligent development,” said Li Dajiong.