The Influence of a Complex Additive on the Hydrophysical Properties of Concrete for Road Construction

The Republic of Kazakhstan is historically located at the junction of Europe and Asia. The famous Great Silk Road passed through the territory of Kazakhstan in the past. The geographical location of the country in Central Asia plays a significant role in the transport and logistics sector, allowing for the transit of cargo to Asia, Europe and back. As is known, the development of the transport system, logistics, and transit transportation contributes to economic growth. Kazakhstan ranks 9^th place in terms of area in the world. That is why it is necessary to connect our cities and regions with high-quality transport arteries, namely high-quality roads. In the presidential message to the nation, President K.K. Tokayev [1] emphasized the importance of reconstructing existing roads and building new ones. The development of the transport sector is also important in the development of the tourism industry in the Republic of Kazakhstan. The country has high transit and tourism potential and therefore improving the quality of roads is one of the top priorities. This article discusses the hydrophysical properties of road concrete and their impact on the durability of road structures. Important characteristics of concrete for work in harsh conditions and sharp continental climates are the properties such as frost resistance and water absorption. The authors propose using additives such as metakaolin, wollastonite and super plasticizer in cement concrete structures. As a result of the research, it was found that the use of metakaolin helps to increase frost resistance to F400 and reduce water absorption by 35%. Thus, this concrete mixture with the addition of metakaolin has a high frost resistance and low water absorption, which increases the durability of the road structure.