© Sergii Tolmachov, Doctor of Engineering, Professor, Professor
of the Department of the Technology of Road Building Material,
ОRCID: 0000-0003-1011-3861, e-mail: email@example.com;
© Olena Belichenko, Ph.D., Senior Researcher, Department of the
Technology of Road Building Material,
© Sergii Pronin, Ph.D., Associate Professor of the Department of
Computer Technologies and Mechatronics,
Kharkov National Automobile and Highway University
INCREASING FROST RESISTANCE OF ROAD CONCRETE BY APPLYING SECONDARY PROTECTION
Abstract. The production of road cement-concrete mixtures, their transportation, laying and compaction usually occurs during periods of high positive temperatures and the presence of wind. When cement concretes harden under such conditions, moisture evaporates from them. This can lead to air shrinkage, which causes to the cracking and collapse of concrete. Therefore, to protect the hardening cement concrete from shrinkage and cracking, film-forming materials are applied to its surface. However, the practice of using road surfaces shows that such protection is not sufficient to ensure the durability of cement concretes. Therefore, to increase the resistance of concrete to aggressive environments, it is proposed to use secondary protection. Secondary protection of concrete consists in applying impregnating compounds to the surface of the pavement.
The article presents the results of studies of the effect of impregnating compositions on water absorption and frost resistance of concrete of strength class B30 (C32/40). It is shown that the use of impregnating compositions improves the water resistance of concrete. However, such surface treatment does not lead to an increase the frost resistance of road concretes. It was found that some formulations increase the hardness of the concrete surface and do not reduce the resistance of concrete under the simultaneous action of negative temperatures and chloride salts. The article presents the results of studies of the effect of impregnating compositions on water absorption and frost resistance of concrete of strength class B30 (C32/40). It is shown that the use of impregnating compositions improves the water resistance of concrete. However, such surface treatment does not lead to an increase in frost resistance of road concretes. It has been found that some impregnating compositions increase the surface hardness of concrete. At the same time, they do not reduce the resistance of concrete under the simultaneous action of negative temperatures and chloride salts. At the same time, there are compositions, the use of which leads to peeling of the concrete surface when tested for frost resistance. Such peeling leads to destruction of the protective layer of concrete and can reduce the frost resistance of concrete. The reasons for the low efficiency of secondary protection of road concrete when using impregnating compositions are given. It is shown that such compositions should be used selectively for the protection of road concrete. It is indicated for which strength classes the impregnation is an effective means of protection. The use of impregnation for concretes of other strength classes leads to a decrease the resistance of aggressive environments.
Keywords: frost resistance, secondary protection, impregnating compounds, concrete protective layer, water absorption.
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