Influence of the fractional composition of the aggregate on the technological and strength properties of HCPV concrete

The use of gypsum-cement-puzolan binder (GCPB) as binders for the production of heavy fine-grained concrete instead of cement binder is a way to reduce the consumption of cement binders, as a result of which CO2 emissions into the atmosphere will decrease. In the building materials industry, products based on gypsum and gypsum- containing binders, with their high manufacturability, are produced without fillers, which leads to a significant increase in the cost of finished products. The purpose of this study was to establish the influence of the fractional composition of fine aggregate on the technological and physical-mechanical properties of GCPB-concrete. The paper presents the results of a study of the effect of the composition of fractionated sands on the physical and mechanical properties of GCPB-concrete. According to the research results, structural concrete was obtained on cast mixes with a strength of 50 MPa on the 7th day of normal moisture hardening. To determine the optimal fractional composition of sand by the method of regression analysis, adequate mathematical models were constructed that describe the physical and mechanical properties of GCPB- concrete. With the help of the constructed mathematical models, optimization problems were formulated and solved to determine the fractional compositions of sands that provide the best values of physical and mechanical parameters of concrete such as density and compressive strength. Solving the problems of optimizing the physical and mechanical properties of concrete depending on the fractional composition of the aggregate, which was used sand of six different fractions, made it possible to predict the composition of GCPB-concrete with a strength of 66 MPa and an average density of 2295 kg/m3.