Introduction. Domestic and foreign experience in the construction of roads with rigid type clothing confirms the prospects for the widespread introduction of cement concrete to ensure their reliable and trouble-free operation for a long period with low maintenance costs. Abroad, the estimated period of operation of hard coatings is 35-50 years, in Ukraine ― 25‒40. installation of temperature and working seams, non-technological repair prevent the introduction of cement concrete in the practice of road construction. Most of these shortcomings can be eliminated using modern materials and technologies. Rigid pavements have a number of advantages, but also disadvantages such as high probability of cracking in concrete slabs and their reflection from the base layers to the coating layers, high capital construction costs, inability to open traffic immediately after construction ― the need to withstand 14 days before set 70‒75 % of strength and 28 days to obtain vintage strength, high noise and vibration when driving a vehicle, the need for temperature and working seams, non-technological repair hinders the introduction of cement concrete in the practice of road construction. Most of these shortcomings can be eliminated using modern materials and technologies.
Problem Statement. The cement-concrete covering of highways works in the conditions of a difficult stressful condition under the influence of repeated loadings from cars and variable temperature-humid parameters. In addition, conglomerate materials such as cement concrete are characterized by internal stresses due to the heterogeneity of their structure, as well as the ongoing processes of structure formation and destruction. One of the ways to increase the durability of cement concrete to cover the floor is the use of chemical additives that can clog pores, give the concrete surface hydrophobic properties. Based on modern ideas of physics and chemistry of surface processes, we can conclude that the introduction of a small amount of organosilicon substances together with the sealing water into the concrete mix will make it possible to significantly improve the durability and resistance to aggressive loading and aggressive factors acting on concrete. Frost resistance, corrosion resistance and durability of cement concrete pavement are greatly influenced by the nature of the total porosity of concrete, the size of individual pores, their shape and the relationship between them. These factors change during the hardening of cement concrete and its operation. These characteristics can be influenced by chemical and physical methods.
Purpose. The purpose of the work is to improve the durability of cement concrete for paving roads by using hydrophobic additives.
Materials and methods. Analysis of scientific publications, technical and regulatory literature to increase the durability of cement concrete pavements.
Conclusions. Thus, as a result of research it was found that the water-repellent additive positively promotes the passage of physico-chemical processes of hydration of cement in comparison with the standard, the optimal amount of additive is in the range of 0.10‒1.15 % by weight of cement; the use of a water-repellent additive allows to reduce the W / C at a given ease of laying due to gas formation; to increase the physical and mechanical properties, crack resistance and durability of cement concrete pavement.
