TECHNOLOGICAL ASPECTS OF STRENGTH AND DURABILITY FORMATION OF SEMI-DRY PRESSED CONCRETE

Technological aspects of formation of strength and durability of semi-dry pressed concrete are considered. The main factor that worsens the performance characteristics of products made of semi-dry pressed concrete has been stated. Deformations resulting from the elastic aftereffect phenomenon are manifested in freshly molded concrete at high pressing force. The factors contributing to the reduction of elastic aftereffect deformation have been determined. The complex application of fibers and plasticizer admixture is proposed in order to reduce the destructive processes occurring in semi-dry pressed concrete in the production of paving slabs. The value of deformations of elastic aftereffect is determined at the pressing intensity of 6, 12, and 24 MPa. An increase of the structural strength of semi-dry pressed concrete up to 320 % was revealed at the age of 4, 6, and 8 hours when reinforced with basalt fibers. An increase of tensile strength at splitting up to 16 % was stated with the combined use of basalt fibers and superplasticizer. The assessment of the durability of semi-dry pressed fiber-reinforced concrete including the water absorption and frost resistance has been performed. Reduction of water absorption of studied concrete with the combined use of basalt fibers and superplasticizer has been stated. A material with a frost resistance grade over F400 has been obtained. The technological line for the production of small-piece products made of fiber-reinforced concrete was developed for the semi-dry pressing method. © 2022, Associated Cement Companies Ltd.. All rights reserved.