Devising approaches to adjusting a strength gain by modified white cements with different c3a content

The object of this study is the mechanism for adjusting a strength gain by modified systems based on white cements with different C3A content. Since white cements have an increased content of the C3A mineral, they are characterized by a drop in strength of up to 10 % in the late stages of hardening. To stabilize the properties of such cements, it is advisable to use modifying additives. It has been established that when a plasticizing additive with a high C3A content is introduced into cement in a small amount (0.5...1 %), as a result of chemical interaction with the mineral C3A, its residue in the liquid phase is not enough to disperse silicate phases. This reduces viscosity of the system. That subsequently leads to a decline in the strength of cement stone, up to 15 %. At the same time, the addition of a plasticizing additive to a system with a low content of C3A turns out to be more effective even at a lower dosage. Modification of cement systems with nano-CaCO3 additives helps stabilize the phase composition of new formations and guarantees the durability of the resulting cement stone. Nano-CaCO3 changes the composition of new formations toward more thermodynamically stable compounds. The introduction of a nano-CaCO3 additive leads to a significant increase in the rate of hydration and creates conditions for the formation of carbonate ettringite. The latter contributes to the directed synthesis of low-base fibrous hydrosilicate phases, including tobermorite, and prevents the conversion of hydroaluminate phases, which eliminates the decline in strength in white cements with an increased content of C3A. Applying modified systems will make it possible to stabilize the strength characteristics of not only white but also colored cements, the introduction of pigments to which leads to a decrease in their strength. This approach will make it possible to effectively use such systems as a basis for decorative concrete and mortars