PREDICTING THE STRENGTH OF CEMENT STONE WITH MODIFIERS FOR SELF-COMPACTING CONCRETE

Modern requirements for the quality of constructural building materials determine the need for the development of highly efficient durable composites based on cement binder. Obtaining such materials implies the use of additives and modifiers for increasing the strength characteristics of concrete and reduce production defects by stabilizing the structure and properties of products. In this research, additives produced by private company limited by shares "NP CMID" (Saint Petersburg, Russia) are used as modifying components of the mixture. They are mineral powder - a multicomponent complex powdered additive for concrete GPM modification 9/12, hyperplasticizer GPMZH–Ultra, modification 17/1. The purpose of this work is to study the effect of the introduction of additives on the strength of the material and to determine the values of the predicted strength in the long-term period of operation. It is demonstrated that the introduction of additives does not affect the character of the strength set. However, it leads to a decrease in the compressive strength by 13 % for mineral powder and an increase by 11 % for mineral powder and plasticizer. There is also a decrease in the amount of tempering water required to achieve standard consistency. The values of the calculated strength in the long-term period are comparable with the obtained data of strength values: all compositions are characterized by an increase in strength up to 100 days of hardening, followed by a damping of the strength set. Thus, the work established the regularities of the effect of additives on the predicted values of the brand strength of the binder: there is an increase in the initial hardening rate and a decrease in the inhibition coefficient of the hydration processes of the binder with the combined introduction of mineral powder and plasticizer. The high strength of the binder makes it possible to predict the high operational characteristics of materials based on it.