Fine-grained self-sealing concrete for green construction of agro-industrial facilities

Abstract

The research results reflecting the features of the technology of fine-grained self-sealing concrete with aggregates from construction waste for the green construction of agro-industrial facilities are presented. The effect of the type and dosage of polycarboxylate superplasticisers on the properties of cement compositions and concrete mixtures was evaluated by rheological characteristics. It has been established that the rheological compatibility of the superplasticiser with a specific Portland cement is achieved with a rational dosage of an additive that does not provoke water separation of cement. A joint assessment of the rheological characteristics of concrete mixtures and strength parameters of fine-grained selfcompacting concrete was performed. A filler from construction waste – sand from crushed concrete – was used as an enlarging component of natural very fine sand. The grain content of crushed concrete in the fine aggregate varied from 20 to 40% with an interval of 10%. When determining the spread of a normal concrete cone, a visual assessment of the spreading character of the concrete mixture was performed. It was revealed that the rheological properties of self-sealing mixtures are more influenced by the dosage of the superplasticiser. The strength characteristics of fine-grained concrete at an early and design age depend more on the content of the enlarging component in the composition of the fine aggregate. It has been established that the maximum strength of concrete, provided that a stable non-delaminating mixture is obtained, is achieved with a rational dosage of superplasticiser and a sand content of crushed concrete in an amount of no more than 35%.