Microwave System for Accelerated Curing of Concrete Repair.

This study presents a novel prototype microwave system developed to accelerate the curing of concrete repair patches. The system incorporates a 2 kW magnetron, a radiation safety enclosure, and a temperature monitoring unit to ensure safe and controlled operation. The prototype advances beyond prior microwave curing systems by incorporating real-time temperature feedback, automated data acquisition, and power modulation to minimize non-uniform heating and prevent localized overheating. Field trials were undertaken on concrete slabs of varying thicknesses, up to 80 mm, including both proprietary repair materials and conventional cementitious concrete. Each slab was exposed to microwave heating for approximately one hour at constant power levels ranging from 1,500 to 2,000 W. Resulting temperatures ranged from 40.4°C to 48.5°C across specimens, with one exceptional maximum of 76.5°C, for a predetermined time. The estimated energy consumption was 25⁢kWh/m3. Data obtained from these trials were employed to validate a previously developed predictive equation for temperature rise in concrete specimens, originally derived from laboratory investigations. The findings indicate that microwave heating can rapidly increase the temperature of concrete repairs, thereby effectively accelerating the curing process for slabs up to 80 mm in thickness. The proportional integral derivative (PID) algorithm was used to control the power supply and temperature in the field trials. A fixed time power regulation (FTPR) algorithm is presented as a proposed refinement intended to further improve power distribution and temperature uniformity. The results demonstrate that microwave heating can rapidly and efficiently accelerate curing for slabs up to 80 mm thick, supporting the potential for energy-efficient, cold-weather concrete repair applications.