COMPREHENSIVE STUDY OF MODIFIED CONCRETE BASED ON ACTIVATED MICROSILICON TOGETHER WITH MICRO-REINFORCING FIBER TO IMPROVE PERFORMANCE

Relevance. The main task of implementing environmental policy is to create a resource-efficient system for the placement and disposal of industrial waste and secondary raw materials, in particular, in the production of building materials and products of specified properties. Within the framework of the study, the authors considered the issues related to the activation of microsilicon, which is a waste of ferroalloy production, and methods of its use for modifying the structure of cement stone, in particular, for heavy concrete. The mechanism of the structure formation, the method of introduction and the optimal consumption of the additive for modifying the concrete mix are determined. Using a comprehensive study, the dispersion products of microsilicon, which is a part of the complex modifier, were determined. It is established that the process of chemical activation of mineral particles has not been sufficiently studied, and therefore the presented research for finding solutions to improve performance through the process of pretreatment of microsilicon with an alkaline medium pH=10,2 together with the micro-reinforcing component, is relevant. The aim of the research is to establish the positive effect of the activation process of microsilicon together with the micro-reinforcing component on modifying the structure of heavy concrete to improve strength, deformative and hydrophysical properties. Object: modified heavy concrete based on activated microsilicon together with a micro-reinforcing component. Methods: x-ray phase analysis (XRD); physical and chemical activation of microsilicon with water treated by electrolysis with the Melesta device; IR spectroscopy using the Varian 640-IR Fourier spectrometer; crack resistance tests using the ADVANTEST 9 servo-hydraulic system; determination of frost resistance in the WK3 180/40 climate chamber; water resistance was determined in the UVB-MG4.01 installation; water absorption using the SNOL electric digital furnace. Result. The positive effect of activated microsilica on the properties of heavy concrete was established by reducing the content of the binder (cement) and replacing it with a microdispersed filler, previously activated with an alkaline medium with pH=10,2. At the same time, there is an increase in the compressive strength of concrete at the age of 28 days by 20,72 MPa in comparison with the control composition. Further modifying complex additive (high water reducing additive «MasterGlenium 115» with the consumption of 1 % plus a reactive chemical additive microsilica brand mku-95 – 15 % by weight of the binder) together with basalt fiber, allows improving the physico-mechanical properties of concrete as well as the hydrophysical ones: water absorption – 2 %; grade waterproofing – W14; frost – F600, which gives the opportunity to put into practice a composition for production of building products and constructions on its basis with specified characteristics under severe operating conditions