Crack resistance of centrally stretched combined re-enforced reinforced concrete elements

Abstract

When laying monolithic building structures in the formwork, the vast majority of concrete are made using plasticizers, which increase their mobility, ease of installation, reduce energy and labor costs..

The plasticizer is made on the basis of ecologically safe biopolymers which form useful, safe microorganisms - cellulose type, lignin-pectin type (microfibers), alkaline earth metals (calcium), alkali metals (potassium, sodium), hydrocarbon, protein type (polymer molecules), phosphorus compounds and other. Bioplast-1 is a thick syrupy liquid of brown color with a concentration of 50 - 60%, density 1.25 - 1.29 g/cm3. It is used for the manufacture of precast reinforced concrete prestressed and monolithic structures, for operation in non-aggressive and aggressive water and gas environments. The use of plasticizer can increase the mobility of concrete by 8 - 12 cm relative to the initial settling of the cone (OK) relative to concrete mixtures without additives (OK 2 - 4 cm). Consumption is 0.15 - 0.5% by weight of cement in terms of dry matter. The action of the additive can reduce water consumption by 13% at a cement consumption of 300 to 550 kg per 1 m3 of concrete mix.

The influence of the plasticizing ecological additive "Bioplast-1" Bioplast-1BL and Bioplast-1B on the mobility of the concrete and the strength of concrete cubes is considered in the work. The paper also establishes the criteria and properties of plasticizers on the properties of concrete mixtures and strength characteristics of concrete that are widely used for the manufacture of prefabricated structures .

The work was performed in two stages: to study the plasticizing effects of Bioplast additives on the concrete mixture; and in the second stage included determining the effect of the additive on the strength of concrete.

The new study of the effectiveness of the additive Bioplast-1BL, Bioplast-1B was performed to determine the effect for which it is intended. It is investigated that the biotechnological plasticizer "Bioplast" increases the mobility of the concrete mixture, increases the strength of concrete. The increase in concrete with the addition of "Bioplast-1BL" is 14% and 10% with the addition of "Bioplast-1B". When the consumption of plasticizer 0.5% by weight of cement in terms of dry matter.