Investigation into effect of metakaolin-based additives incorporation on formation of cement stone structure

The paper presents studies on the evaluation of the effect of complex additives, including metakaolin, microsilica and superplasticizer on the formation of the phase composition of cement stone. The change in the structure of the modified cement stone was studied and the dependencies were established. A comparative analysis of two complex additives to evaluate the effect of metakaolin on the change in the phase composition of cement stone was carried out. The possibility of obtaining high-performance concrete with low porosity, high early and vintage strength, durability, using additive accelerators and structure modifiers has been investigated. It is established that the use of metakaolin leads to the formation of a cement stone structure, mainly consisting of metastable calcium hydroalumates. It is necessary to use metakaolin together with microsilica and superplasticizer to create a dense structure of cement stone with low capillary porosity from stable low-basic weakly crystallized hydrate phases that are stable when the medium pH is changed.