Cold water concreting technology using thermoactive formwork

Abstract

The paper presents the study results of temperature and strength indices of structures while performing isothermal warming in thermoactive formwork. The effectiveness analysis of thermoactive formwork panels warming in the freezer with complex additive was also carried out. Thermoactive formwork is a box-shaped structure consisting of 20 mm thick panels of laminated plywood with built-in wires. The total size of the thermoactive formwork for concrete construction was 200×200×200 mm. Concrete mixture was laid in thermoactive formwork in layers and caked by rodding. Then concrete mixture was warmed up using heating wires. Samples were placed in the freezer at a temperature of 18 °C for 1, 3, 7, 28 days. However, the samples were kept in a positive temperature of about 16 °C during the first ten hours while the concrete mixture was stored in the freezer.According to the experiment results it was established that the lowest temperature was in the center of a formwork, which proved that this formwork could be used at an ambient negative temperature. It was revealed that heavy weight concrete with complex additive had a compressive strength higher by 57 compared to the control sample.