Electric activation curing behaviour of reinforced concrete beam under severely-cold environment: Breakthrough of rapid concrete manufacturing at cold region

Rapid on-site fabrication of concrete structure in severely-cold environment is a tough problem. Electric activation (EA) curing exhibited significant advantage on preparing laboratory-scale cement mortar at negative temperature, however, the feasibility of this curing method on manufacturing full-size concrete structure needs to be investigated. In this work, EA curing was proposed to rapidly manufacture on-site reinforced concrete (RC) beam in practical cold environment. The specific development regularity of the electrical resistance for EA cured RC beam was theoretically predicted and experimentally verified, and the electrical resistance of EA cured beam kept in a stable increasing trend during the whole curing process, regardless the harsh environment. Moreover, the temperature field distribution inside the structure was also clarified, it was found that EA curing could maintain a uniform temperature field distribution of RC beam at around 45 ℃ during the whole EA curing process. Further, mechanical property results revealed that EA curing could rapidly promote the strength formation of RC beam under severely-cold environment with the 2-day compressive strength of 28.4 MPa, reaching C30 concrete strength grade. In addition, this work firstly revealed the structural performance of EA manufactured RC beam, which exhibited higher ultimate flexural bearing capacity (233 kN) comparing with standard curing manufactured beam of 215 kN. This work gives a thorough investigation over the performance development of RC beam subjected to EA curing under extremely-harsh environment, making a breakthrough towards rapid fabrication of high-quality concrete structure at winter in cold regions.