Innovative Structural-Heat-Insulating Concrete for Insulation and Stability Rise of Frozen Foundation Soils

Abstract

Purpose: To create highly effective heat-insulating structural concrete, recommended for insulating and preventing permafrost soil thawing. Methods: When conducting research, we used GOST (Russia State Standards) 25820-2014 “Lightweight concrete. Specifications”, GOST 25485—2019 “Cellular concrete. General technical conditions”. Determination of strength and processing of results according to GOST 10180-2012 “Concrete. Methods for determining strength upon control samples”; thermal conductivity coefficient was determined according to GOST 7076-99 “Construction materials and products. Method for determining thermal conductivity and thermal resistance at stationary thermal regime”; frost resistance of concrete according to GOST 10060-2012 “Concrete. Methods for determining frost resistance”; density of concrete in natural moisture state- according to GOST 12730.1-2020 “Concrete. Density determination methods”. It has been established experimentally that in order to create highly efficient heat-insulating-structural concrete, it is advisable to use as a filler a foam glass of fraction 1.25–2.5 mm, D250, λ ≈ 0.06 W/ m · °C, and for to create strong and reliable matrix on cement basis it’s effective to use finely dispersed microsilica in combination with complex chemical additive on polycarboxylate basis, modified with nano-dispersions of silicon dioxide, SiO2. Results of physicalmechanical studies have confirmed that it is effective to use particles of silicon dioxide together of micro- and nano-size in combination with surfactants represented by polycarboxylate polymers, meanwhile, foamed glass concrete with the best compressive strength and tensile strength at bending a rises significantly, coefficient of resistance to cracks of nanomodified foam glass concrete, Ktr. = Rbend./Rcompress. = 3.6/13.3 = 0.27, has rather high value which should provide for increased resistance to cracks and for reliability for a protective coating. In order to increase density/strength without deteriorating heat-insulating indicators it is advisable to use additionally a finely-ground blast-furnace slag as a filler which a rises cohesion of foam glass concrete mixture and strength of foam glass concrete. Practical significance: Rational ratio of components of nanomodified foam glass concrete mixture ensures the creation of highly mobile foam glass concrete mixture with good workability, and on the mixture basis, a unique heat-insulating-structural material is formed with the following characteristics: D900; λ = 0.14 W/m·°C, B12, Btb2.9 F1300 that defines it as a thermal insulation material of increased reliability and durability, which is advisable for recommendation for the Arctic harsh regions.