Modification of Hydraulic Engineering Concrete Properties by Additives Based on High Molecular Weight Compounds

Abstract

Ensuring high water resistance, frost resistance and corrosion resistance of hydraulic structures is achieved by creating concrete with a dense structure that can absorb aggressive influences. This is possible by modifying the structure of concrete with polymer additives of new generation. The introduction of polymer additives has a plasticizing effect and contributes to the preservation of technological properties of the concrete mixture, modifies the pore structure of concrete and influences the formation of cement stone strength. The paper presents the results of research on the effect of polymer additive based on polyvinylpyrrolidone on the basic properties of Portland cement binder. It was found that the compressive strength at the age of 2 days increases by 7% at the content of polymer additive in the amount of 0.8%. Also, in-troduction of polymer additive increases the compressive strength at the age of 28 days at its content of 0.6 and 0.8% by 22 and 27%, respectively. The effect of polymer modifier on the formation of the initial structure, manifested in the increase in the time of the beginning and accel-eration of the end of setting has been established. The kinetics of heat release of cement dough in the presence of polymeric modifier in the amount of 0.6 % has been studied. The data on the phase composition of cement stone in the presence of polymer modifier are given. It is established by means of electron microscopic analysis that the introduction of polymeric admixture promotes modification of cement stone microstructure with formation of more dense homogeneous structure. The given research results are taken into account in the development of concrete compositions with a set of specified properties required for the construction of hydraulic structures.