Increase of Impact Strength and Frost Resistance of Concrete Hydrotechnical Piles at Deaeration of Concrete Mixture with Air-Entraining Admixtures

In the article the main technological factors of influence on frost resistance of concrete are given. It is proved, that the reduction of air content in concrete mixture with air-entraining admixtures during continuous vibration does not lead to a decrease in frost resistance of concrete with an increase in its strength. The completed researchers have shown that when the concrete mixture is deaerated, the number of micro-destructions under the impact effects on concrete is significantly reduced. The obtained data allowed to offer a method of manufacture of piles, submerged by impact effects, for severe climatic conditions. The main parameters that must be provided during the production of piles and their clogging for increased durability are indicated. Deaeration of concrete mixture with air-entraining additives and initial air content does not lead to decrease of subsequent frost resistance of concrete. The creation in concrete mixture of initial excess air content increases mobility of concrete mixture, and subsequent deaeration allows getting concrete of especially high frost resistance with increase of its tensile strength. Deaerated concrete allows to increase the level of multiple impact tensions without further reduction of durability. This method of obtaining high-frost-resistant concrete of increased impact tensile strength is expedient to use in manufacturing piles for sea hydraulic installations. The tensile strength of concrete piles (after deaeration) should be not less than 50 MPa.