Fast-Curing Composites Based on Multicomponent Gypsum Binders

Abstract

The novelty of the paper is to identify the scientific patterns of the selective effect of multicomponent fine mineral additives on the synthesis of new growths and the microstructure of gypsum composites. Gypsum binders obtained using the waste of wet magnetic separation of ferruginous quartzite, nano-dispersed silica powder, chalk, and superplasticizer were prepared as novel compositions, on the basis of which rational compositions of gypsum composites for various purposes are created. The strength characteristics of concrete mixes were researched by a series of tests (compressive strength and flexural strength). In addition, the durability characteristics (freeze-thaw resistance and water impermeability) as well as thermal conductivity were determined by standard techniques and confirm the creation of durable composites with high exploitation properties. Besides, the microstructural, morphological, and thermal properties of such composites at 28 days of curing were determined. The technology of composite gypsum binder preparation has been developed, contributing to the uniform distribution and optimization of the particle size distribution of its components. It also accelerates the process of microstructure formation and increases the compressive strength in the early periods of hardening by 40% and at 28 days old by 58% with compressive strength values of up to 26 MPa and a water resistance coefficient of 0.82–0.89. Rational compositions of gypsum composites are offered for various purposes with multicomponent fine-dispersed mineral additives and superplasticizer, reducing their water demand by 19% with little or no reduction in the strength of equal-moving mixes and slowing down the setting time by 3 times (up to 22 min 20 s).