Increasing the performance properties of hydraulic concrete using ultra- and fine-dispersed additives

Taking into account the constantly growing requirements for the quality, reliability and durability of concrete structures for hydraulic structures, there is a need to develop hydraulic concrete compositions with improved performance properties. The aim of the study is to improve the physico-mechanical and deformative properties of hydraulic concrete using finely dispersed aluminosilicate rocks – perlites and colloidal additives in the form of silicic acid sol. The object of the study is modified hydraulic engineering concrete based on a composite binder using finely dispersed vitreous and crystallized perlite, silicic acid sol and a polycarboxylate-based superplasticizer «Polyplast». Results of the study: The choice of silica-containing additives is substantiated and it is shown that their use has a positive effect on the properties of hydraulic concrete. The effect of complex modification on the properties of hydraulic concrete was established by reducing the content of Portland cement and replacing it with finely dispersed glassy perlite, pre-crushed to a specific surface of 300-600 m2/kg, introducing silicic acid sol and the superplasticizer "Polyplast", which make it possible to improve the physical, mechanical, deformation and hydrophysical properties: compressive strength - 53.4 MPa; ultimate tensile strength in bending - 10.9 MPa; crack resistance coefficient - 0.20; prismatic strength - 46.3 MPa; modulus of elasticity 37.345 MPa × 103; Poisson's ratio - 0.199, water absorption - by weight - 2.43%; water resistance grade - W16. It has been proven that by adding finely dispersed perlite, silica sol and superplasticizer Polyplast to Portland cement, it is possible to obtain hydraulic concrete characterized by strength indicators not inferior in strength to the control composition, and with increased indicators of water resistance and crack resistance compared to traditional compositions.