Влияние среды замораживания на показатели времени жизни асфальтобетона

Abstract

Приведены результаты определения влияния воды, солевого раствора и циклического замораживания-оттаивания образцов на показатели прочности, времени жизни и средоустойчивости асфальтобетона. В ходе экспериментов было определено, что циклическое замораживание-оттаивание без дополнительных факторов оказывает незначительное влияние на прочность при изгибе, однако сказывается на прочности при сжатии; использование чистой воды вносит ощутимый вклад в потерю прочности асфальтобетона. Наибольшее негативное влияние на прогноз качества асфальтобетона оказывает циклическое замораживание-оттаивание с 5 % раствором соли.According to the Kharkov hydro meteorological center there are about 50 freeze-thawing cycles per one winter in the Eastern Ukraine. Purpose of this investigation was definition of influence of water, saline solution and cyclic freeze-thaw of samples on the strength indicators, life length and resistance to media of asphalt concrete. Type "G" asphalt concrete with 6.5 % of bitumen with penetration grades 60/90 was investigated. It has been chosen because it is more homogeneous, which reduces the manifestation and influence of structural defects. In a result it was determined that cyclic freeze-thawing without additional factors slightly affects at flexible strength but strongly affects at compressive strength. It have been chosen two kinds of samples beam-samples (4*4*16 sm) and cylindrical samples (71.2 mm in diameter). The results of investigation are as follows: cyclic freeze-thawing with pure water makes perceptible contribution at strength loose of asphalt concrete in all investigated conditions. It was clarified that cyclic freeze-thawing renders the most negative affect at prediction of quality of asphalt concrete when it with 5 % saline solution. Separated influence of water without cyclic freeze-thawing has less destructive influence at the flexible strength and life length whereas influence of 5 % saline solution is much more aggressive for the asphalt concrete. To determine the stress state scheme, the degree of reduction in strength after the cyclic freeze-thawing, the compressive strength parameters along the generator in the condition of different rates of deformation of the initial samples and samples after residence in the air and water medium were made. This article also gives a summary, based on the experimental data of flexible strength, that the static load has its great negative influence on the asphalt concrete then dynamic one.