Zakharov D. Road cement concrete with high flexural strength

The thesis is devoted to the actual problem of increasing the flexural strength of road cement concrete by increasing the effectiveness of its structural components. For its solution, based on the analysis of literary data, the main components of the concrete are determined, which influence on the flexural strength of concrete. Theoretical understanding of the effect of chemical and active mineral additives and their complexes on the structure formation processes in the contact zone of cement stone-aggregate was further developed. It is shown that the introduction of an active mineral additive leads to the formation of a large amount of low-basic calcium hydro-silicates, mainly in the contact zone and the adjacent zone, which has been experimentally proved. The mechanism of the influence of the flat particles is proposed and substantiated. It has been shown that during vibrocompaction, flat particles move to the upper part of the concrete, and at the same time, increased porosity is formed under them and in the contact zone. With the aid of optical microscopic studies of the concrete structure, the mechanics of the action of an active mineral additive, which consists in the dispersion of large air bubbles and the formation of an increased number of micropores, is proposed and substantiated. Conducted calculations that confirm this. It is shown that with the introduction of the optimal amount of polypropylene fiber of the required geometric dimensions, the flexural strength of road concrete and its frost resistance increase. Physical and chemical studies of the hydration products of cement stone, which contains an organic-mineral complex and a mineral additive, have been carried out. Conducted pilot implementation of research results. A draft state standard of Ukraine, and 4 regulatory documents. The calculation of the economic effect was carried out.