We perform chemical grouting for two different markets: geotechnical and waterstopping/large diameter pipe repair.
Geotechnical Chemical Grouting
For the geotechnical market, chemical grouting is generally performed for soil stabilization (also called soil modification). In this application, we inject chemical grout into soils to improve their bearing capacity or slow groundwater migration through soils.
Chemical grouting for geotechnical applications may be performed with grouts which either expand or do not expand. Single component prepolymers which expand are excellent for economically reducing the permeability of granular soils such as sands, cobbles and other materials while also improving bearing capacity. Single component polyurethane resins excel at significant increases in bearing capacities of sandy soils.
Chemical grouting is also used for filling deep voids within soils.
Non-expanding Chemical Grouts
Non-expanding chemical grouts are generally used to bind loose soils to improve bearing capacity. Non-expanding chemical polyurethane resins react with water in the treated soil (water can also be introduced, if needed). Catalyzers are used to control the reaction speed of single component chemical grouts. Depending on the application, desired compressive strength and soil type, we install non-expanding chemical grouts from various manufacturers.
Expanding Chemical Grouts
Expanding chemical grouts are typically prepolymers. Expanding chemical grouts typically offer lower peak compressive strengths of the treated materials. Prepolymers can treat more volume of soil per unit of grout than non-expanding chemical grouts. Therefore, expanding chemical grouts are used primarily for reducing migration of flowing soils and reducing water flow through soils. Expanding chemical grouts are excellent for water cut-off applications. Acrylamides, which are frequently used in the grouting of sanitary sewers fall into this category.
Waterstopping Chemical Grouting
We perform waterstopping chemical grouting to stop water intrusion into pipes and buried structures such as tunnels, culverts and facilities. Depending on the nature of the adjacent soils and accessibility of the structure experiencing water intrusion, single component expanding prepolymers, and plural component expanding polyurethanes can be injected to stop water leaks into various structures.
Single Component Polyurethanes
Single component prepolymers are either injected into the soil adjacent to a structure or through the walls of a structure. Single component polyurethanes are catalyzed at various ratios to control their reaction speed. Different grouts have different viscosities, final densities, and reaction profiles. Therefore, leak characteristics are important in determining the most appropriate single component chemical grout.
Prepolymers are subject to washing out in fast water flows.
Plural Component Polyurethanes
Plural component polyurethanes are injected immediately adjacent to a structure through the structure. Plural component polyurethanes generally have a more uniform cell structure than single component foams. Plural foams excel where there are large voids or very fast water flows which would wash out single component chemical grouts.