Residual strength of cylindrical elements with cracks healed by using the injection technology

Injection Technologies for the Repair of Damaged Concrete Structures

“…The necessary technological routes, applicable in field conditions and commercially feasible, are developed, preventing opening of the injection composition-filled crack and/or repeated water inrush, including [10], [30]- [36]:…”

“…Therefore, world production volumes of polyurethane foams are twice as high as the volumes of all other foam plastics [27]- [29]. Therefore, mass polyurethane products include simple and complex polyesters, catalysts, and foaming agents in formulations of the component A and diisocyanates of the diphenylmethane series or polyisocyanates in formulations of the component B [25]- [30]. Interaction between excess diisocyanates or polyisocyanates (the component B) and hydroxyl containing polyols (the component B) during preparation of the injection compositions results in the formation of polyurethane fragments, so-called pre-polymers.…”

“…With this purpose, we reduce the boundary problem describing the loading configuration of the disk with the filled crack to the following singular integro-differential equation in respect to unknown crack edge displacements in the section − l ≤ x ≤ l [30] (Fig. 6.49):…”

“…Such materials first include two-component (polyol-polyisocyanate) polyurethane systems[30], [41]-[43]. Therefore, only those injection polymer compositions that are able to substitute water in concrete surfaces and/or chemically fix it with the formation of high-molecular compounds stable over long-term service are preferable in the case of wet cracks.…”