THE INFLUENCE OF THE TECHNOLOGICAL MODE OF COMPACTION OF CONCRETE MIXTURE WITH FLY ASH AND MICROSILICA ADDITIVES ON THE STRENGTH OF CONCRETE

Abstract

The aspects of expanding the scope of application of non-reinforced products, in particular, pipes with sufficient strength indicators, were considered, and the objective necessity of developing appropriate concrete compositions and compaction technology, as well as the nomenclature and parameters of additives, was confirmed. The article outlines the trends of increasing concrete strength characteristics due to the rationalization of methods of concrete compaction with the use of waste. It has been confirmed that for the material of the pipes it is necessary to ensure the increased tensile strength of the product. After compaction, it is necessary to remove the liquid from the concrete, which ensures maximum convergence and unification of the particles of the solid phase. The method of iterations was used to determine the influence of each of the factors of concrete strength research on tension. Considered methods of concrete mixture compaction, according to the features and rheological properties of which two principles are implemented during compaction: removal of excess entrapped air and excess water from low-mobility and rigid mixtures by external influence and removal of air from high-mobility mixtures. Special attention was paid to the technologies of compaction by pressing, vacuuming and vibrovacuuming. Samples of concrete compacted by pressing and vibrovacuum ensured the production of concrete of almost the same structure with compaction of all components. Test results, electron microscopy of cement stone, radiographs obtained with different methods of compaction are presented. An increase in the degree of crystallinity was recorded due to the higher speed of reaching the supersaturation of the liquid phase of the cement test during hydration. When processing the research results, a regression analysis was performed, and analytical models for predicting parameters were obtained. The results were obtained that the fine-grained concrete mixture when compacted by pressing provides an increase in strength under the condition of pressing in layers.