Shotted Concrete and Injection Mortars for Comprehensive Repair of Under-ground Structures

Abstract

Theoretical foundations for increasing the efficiency of shotcrete and in-jection mortars based on composite cement (CC) have been developed, which consist in creating a high-density packing of hydrate new growths with an impact-resistant structure through the use of new nontraditional raw materials (aluminosilicates obtained by the developed technology). As a result, an increase in the early compressive strength of shotcrete from the use of CC by 62%, in bending - by 90%, and the impact strength coefficient - by 80%; at the same time, the water-tightness grade W16 was achieved. Scientifically based methods have been developed to control the structure formation of a low-porous cement material with the strengthening of the contact zone between the old and new concrete layers by selecting components in a rational proportion and granulometry, which makes it possible to create a shotcrete layer similar to the base matrix of the reinforced wall. A wide range of injection solutions from composite cements ground to a specific surface area of 450 m²/kg has been developed[1].

[1] Funding. The research was carried out with the funds of the state program of the Russian Federation "Scientific and Technological Development of the Russian Federation" for 2021-2030 within the Plan of Fundamental Scientific Research of the Russian Academy of Architecture and Construction Sciences and the Ministry of Construction of Russia for 2022, topic No. 3.1.2.8 «Development of theoretical and technological foundations for obtaining road and airfield concrete pavements of increased durability with the addition of hydrothermal nano-silica of volcanic origin»