UTILIZATION OF IOT TECHNOLOGY FOR REAL-TIME MONITORING OF CONCRETE DEFORMATION USING SURFACE-MOUNTED STRAIN GAUGES

Abstract

Shrinkage and creep of concrete are major causes of cracking, load capacity reduction, and shortened service life of structures. Traditional monitoring methods are often discontinuous, expensive, and unable to detect early anomalies. This paper presents the design, fabrication, and pilot validation of a real‑time concrete deformation monitoring system using Internet of Things (IoT) technology with a resistive strain gauge directly attached to the specimen surface. The system comprises KC‑70‑120‑A1‑11 strain gauges, NTC 10K temperature sensors, an ESP32 microcontroller, and an MQTT server. A detailed experimental procedure was carried out on three prismatic concrete specimens (100×100×400 mm; n = 3). Results over 28 days showed a shrinkage strain of 245.8 με, a creep coefficient φ = 1.292, and an average error of 4.5% compared to the CEB‑FIP 2010 model. As a pilot observation on one poorly cured specimen (M3), the system detected abnormal deformation (cracking) 42 hours earlier than manual visual inspection. Due to the small sample size, these findings should be considered preliminary; further validation with larger sample sizes and reference instruments (e.g., LVDT) is necessary. This study demonstrates a low‑cost IoT application direction for structural health monitoring in laboratory and pilot field conditions.