Influence of freezing on the bond strength of concrete joints in winter concreting

The object of this study is concrete seams and joints in large-panel buildings. The research was carried out in order to assess the effect of early freezing on the adhesion strength of concrete joints and to identify the characteristics of active and passive methods of winter concreting of joints in prefabricated structures. Laboratory research methods were applied on prism samples made of self-sealing fine-grained concrete mixtures. The dependences of the effect of freezing on the adhesion strength of concrete joints and the compressive strength of concrete at an early age as a result of freezing, thawing and subsequent hardening under normal conditions were obtained. A favorable effect on the strength of preheating joints was determined. An assessment of the shortage of the design strength of joints during "cold" concreting was performed. The results of the study make it possible to significantly expand the scope of application and increase the energy efficiency of non-heating methods of winter concreting.