Modified heavy concrete based on activated micro-silica for sleepers of high-speed highways

A method has been developed for the synthesis of a complex additive based on ultrafine silica and superplasticizer “Plasticite RK”, which allows to obtain modified concrete with a given set of operational properties. The problem of reducing the consumption of micro-silica and increasing its efficiency in cement concretes due to chemical activation is solved. The effect of activation of microcosm in an acidic medium (pH =2.1) enriched with oxonium H 3 O + ions and h+ cations is experimentally confirmed, and in an alkaline medium(pH=10-11) enriched with hydroxyl groups of OH-anions of OH-, with the production of dimers of orthosilic acid Si(OH) 4 , formed during chemical dispersion of microcosm are additional centers of crystallization, which concentrate new formations around themselves, forming a stable colloidal system. It has self-reinforcing processes associated with the recrystallization of colloidal size neoplasm particles into larger ones that participate in the construction of a spatial framework, which is compacted and strengthened due to prolonged hydration, contributing to an increase in the strength characteristics of cement stone and, accordingly, concrete. The use of chemical activation of micro-silica with water treated by electrolysis and enriched with hydroxyl ions OH - with pH=10-11, introduced into the matrix of the concrete mixture, in a comparative analysis showed an increase in strength by 58.8 % in comparison with the control sample of the factory composition without the use of micro-silica as part of a complex additive.