Influence of Polycarboxylate Superplasticizer and Mineral Additives of Various Compositions on the Technological and Physical-Mechanical Properties of Cement Systems

Abstract

Management of the pore volume and the mineral-morphological state of the hardening system by modifying the cement stone with chemical and mineral additives introduced both separately and in complexes is considered to be one of the defining directions of concrete structure formation. The purpose of this study was to establish the regularities of the influence of mineral additives of various compositions (siliceous, aluminosilicate, sulfoaluminate, carbonate) and polycarboxylate superplasticizer on the technological and physical-mechanical properties of cement systems, with the identification of the most effective modifiers and their complexes. Based on the results of experimental studies, it was established that it is possible to obtain, on the basis of sulfoaluminate modifier, compositions with high technological parameters with a reduced content of expensive polycarboxylate plasticizer. It was found that the studied compositions with mineral additives differ in high rates of compressive strength gain of cement stone at the age of 3 and 7 days - 48÷69 and 71÷83% of the compressive strength at the age of 28 days, respectively. At the same time, in comparison with the reference composition without mineral additives, the relative compressive strength of the modified cement stone at the age of 28 days varies in the range from 0.9 to 1.2 relative units, which confirms the possibility of increasing the strength indicators of cement composites due to the use of optimal complexes of polycarboxylate superplasticizer and mineral additives of various compositions, in particular when using microcalcite, microsilica and sulfoaluminate modifier together.