In the article, using the method of mathematical planning of the experiment, the influence of formula and technological factors on the properties of hardened multicomponent gypsum-cement binders with a mineral additive finely ground to a specific surface of 300-700 m2/kg of quartz sandstone crushing screening (QSS) JSC Lebedinsky Mining and Processing Industrial Complex, Gubkin, Belgorod region, Russia was determined.
It has been established that the use of finely ground QSS as part of a gypsum cement binder with a ce-ment/QSS– 1/2 ratio contributes to ensuring its operational characteristics and stability of properties during solidification at the required level, contributing to a decrease in the concentration of CaO in the liquid phase of the hardening system.
The optimization task was to determine the conditions for the preparation of a gypsum-cement mixture with a movement of ≤ 120 mm (according to Suttord) and the beginning of the setting time of ≥ 6 min, with the provision of the maximum compressive strength of the hardened binder. An active 3-factor experiment was planned. The following were studied: the compressive strength of hardened gypsum-cement binder samples in 2 hours of hardening – Rcomp2(Y1); at 28 days of age – Rcomp28(Y2); as well as the mobility of the gypsum–cement mixture – P (Y3) and the timing of the beginning of setting - T (Y4). With the help of mathematical processing of the results of experimental studies, regression equations were obtained and with the help of nomograms constructed on the basis of mathematical expressions, the rational compositions of gypsum cement compositions were graphically and analytically determined.