A technology of erecting high-rise building frame structures using B60-B100 classes high-strength concretes

Abstract

Introduction. The article presents a technology of erecting of high-rise building's frame structures made of B60-B100 classes high-strength concretes. This technology includes a complex of processes and considers a number of special features, the most significant of which are connected with the specific character of high-strength concretes and concreting climatic conditions.Aim. To determine the main requirements for the technology of concreting and parameters of curing the monolithic structures of high-rise buildings made of B60-B100 classes high-strength concretes, including at winter periods, at the various stages of their erection.Methods and materials. Studies were carried out on the effect of hardening temperature variations from +5 to +50 °С on the hardening kinetics of B60, B80, and B100 classes concretes. Based on the 15-year experience of the “Moscow-City” construction, the mix proportions of high-strength concretes were optimized, as well as the main technological parameters of concreting and curing the frame structures located at an altitude of up to 370 m were analyzed and summarized.Results. The mix proportions of B60-B100 classes concretes of high-workability and self-compacting mixtures with a cement consumption of 350–480 kg/m3 was optimized using standard materials and MB-type organomineral modifiers. The performed study revealed a regularity between the strength and the temperature-temporal parameter of concrete curing, which is applicable for a preliminary assessment of strength characteristics in high-strength concrete structures on the basis of their temperature measurement results. A systematic approach to concrete curing and the maintenance of building structures as a whole with the vertical division of a high-rise building into four temperature zones led to a reducing the probability of thermal cracks appearance.Conclusions. According to the results of the study, the proposed complex of technological solutions concerning compositions and properties of concrete mixtures and concretes, the technology of concreting, as well as the methods of heating and curing the concrete of structures at the various stages of their erection ensures thermal resistance to cracks at the early stage of concrete hardening, as well as the high quality and assigned rates of construction.