The issue of strengthening a two‑storey building was solved using self‑expanding geopolymer columns.

Construction of the two‑storey house began in winter. The underlying layers of loamy foundation were excavated and replaced with two metres of gravel with a particle size of up to 32 mm. The rubble foundation was made of stone measuring 100–250 mm. A gross mistake was the reinforcement of the foundation soil with construction waste at a depth below 2 metres from the ground surface. Ice accumulated in the pores of the fill material (construction waste), which caused future settlement. When the warm period arrived and the ambient temperature rose, the ice melted, causing settlement of the building facade from 4 to 30 mm. The loosened areas were at a depth of 1.4–1.7 m.

Technology applied:
The basis of the chosen solution was the Deep Injection geopolymer column technology. URETEK geopolymer was used as the base to create a solid foundation support and to transfer and evenly distribute loads from the building structures. Using additional injection points of auxiliary URETEK compositions, the house was lifted with an accuracy of 4 mm. After that, deep injections were performed in the damaged area to compact the foundation down to 0.5 m below ground level. Then, using continuous injections, geopolymer columns were installed under the load‑bearing structures.

After identifying the problem zone at a depth of 1.4–1.7 m (during dynamic probing), it was found that the loose gravel, after the ice melted, had become additionally compacted, which created the problem of voids and cavities. Injections of geopolymer, which has low expansion properties with very high density, were made into these zones to create a solid foundation base. The next step was the installation of polymer columns directly under the foundation footing to make it possible to transfer loads to the strengthened layers of the foundation.