Deformation of Early Freezing Concrete in the Assessment Stress-Strain State of Reinforced Concrete Structures

When performing concreting works for structures in sub-zero temperatures, a situation often arises in which the technology of heating the concrete mix during its setting and hardening is violated. It is customary to specify in the project the minimum (critical) strength of concrete before its freezing to ensure the strength gain to the brand indicators. Low strength of concrete at the time of freezing is the basis for dismantling the structure or reinforcing it. As a result — a decrease in the profitability of construction and an increase in the terms of production works. The paper presents a technique for constructing a deformation diagram of concrete samples after early freezing of the concrete mix in order to use it to assess the stress-strain state of structures with low strength. To assess the effect of early freezing times on the final strength of concrete and to plot deformation curves, compression tests were carried out on cube samples with an edge of 100 mm with different periods of curing of concrete before its freezing. A technique is presented for taking into account the obtained deformation curves for assessing the stress-strain state of structures based on a nonlinear deformation model. Initial information has been prepared for developing a program for calculating the SSS using the obtained methodology. The results obtained allow for assessing the technical condition of structures after early freezing of the concrete mix, taking into account the changed deformation characteristics of concrete in areas with early freezing of the concrete mix.

early freezing, nonlinear deformation model, stress-strain diagram, cube specimens, critical strength of concrete