Some aspects of structure formation of modified centrifuged concrete using superplasticizers

The article is devoted to the structure formation of modified centrifuged concretes using superplasticizers. It is noted that negative temperatures are one of the most dangerous and severe natural effects on concrete, leading to its destruction, the main cause of which is the freezing of water in the pores and capillaries of the material. The operational characteristics and operability of the supports depend on the conditions of formation of its structure and its condition when concrete is frozen, the degree of saturation of concrete with water, the conditions of freezing and thawing (speed and degree of temperature change, frequency of temperature change, etc.), size and type of structures, degree and type of reinforcement, stress. The characteristic of resistance of concrete at freezing is its mark on frost resistance. To identify the mechanism of increase of frost resistance of concrete with additives in the laboratories of the Department "Technological Engineering and Expertise in the Construction Industry" don state technical University has studied the characteristics of the pore space structure spun concrete compared to vibrated. The structure of concrete was evaluated on the basis of data on the kinetics of water absorption, analyzes of the microstructure on an optical microscope to determine the integral and differential porosity, as well as to identify the features of the microstructure. The studies were carried out on samples of centrifuged (in some cases, and vibrated concrete of the same composition) concrete without additives, with the addition of superplasticizer C-3 in an amount of 0,7 % by weight of cement, with a complex modifier C-Z + Aeromix (0,7 + 0,3 %). The conducted complex researches allow to recommend use of water-reducing effect of superplasticizers for giving to the centrifuged ferro-concrete racks of high durability.