PECULIARITIES OF WORK OF FINE-GRAIN CONCRETE, INTENDED FOR HYDROTECHNICAL STRUCTURES, UNDER THE ACTION OF NEGATIVE AND CHANGING TEMPERATURES

Summary On the territory of Ukraine there is a significant number of rivers and the sea coast. Hydraulic structures in many cities due to their intensive operation are in poor condition. Repair of such structures is usually very time consuming and expensive. The aim of the work was to study the effect on the properties of fine-grained concrete intended for construction of hydraulic structures of alternating temperatures and to provide the necessary strength and frost resistance of this concrete by changing its structure by using organic and mineral additives in the form of hydrophobic surfactant and iron filler. In the process of performing the experiments were used: binder – Portland cement of the Kryvyi Rih Cement Plant, aggregates – a mixture of Dnieper river sand and waste from the mining and processing plant, as a hydrophobic surfactant – sodium oleate. Under the conditions of the experiment, the introduction of sodium oleate and iron-containing aggregate into the concrete composition reduces the change in the linear dimensions of the samples under the action of alternating temperatures. THE compressive and tensile strength of fine-grained concrete was investigated depending on the initial ratio between the components of the dispersed system "Portland cement – aggregate – water – sodium oleate", the type and content of additives that were introduced, as well as ambient temperature. Under the conditions of the experiment during the hardening of the dispersed system "Portland cement – aggregate – water – sodium oleate" for 28 days under normal conditions of use as an additive of sodium oleate leads to an increase in the strength of concrete, both in compression and tensile strength. It is established that the use of mixed aggregate for the production of fine-grained concrete intended for hydraulic engineering, part of which is obtained by grinding rock -bearing rocks, as well as water structured by colloidal hydrophobic surfactants, increases the resistance of concretes to alternating temperatures.