EXPANSION AGENT FOR BACKFILL MATERIAL Russian patent published in 2018 - IPC E21B33/138 C09K8/467 

FIELD: construction materials.

SUBSTANCE: invention relates to the field of building materials, in particular to the compositions of complex additives used in the production of concretes, mortars, concrete and reinforced concrete products, including the processes of cementing oil and gas wells. Expansion agent for the oil well contains 70–83 wt % of shale ash, 14–24.5 wt % metakaolin and 2.2–6.3 wt % superplasticizer based on polycarboxylates Melflux 1641 F. In this context, shale ash has a mass fraction of free calcium oxide of at least 14 %, and the rest on the sieve No. 008 is not more than 35 %.

EFFECT: technical result is to provide the adjusting capacity with the aid of an expansion of backfill material in time with the aim of concrete reducing shrinkage deformations and increasing the density of the backfill material.

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