ACI 351.1R, ASTM C827, ASTM C1107, ASTM C939, ASTM D4218 (polyurethane systems)

• GPR scan to locate and map subsurface voids before drilling.
• Probe drilling at representative locations to confirm void depth and extent.
• Document void locations, estimated volumes, and access conditions in written report.

• Non-shrink cementitious grout per ACI 351.1R: flowable or thixotropic per application.
• Drill grout holes at specified pattern and depth per grouting plan.
• Pressure test each hole before grouting; monitor grout take during injection.
• QC: cube specimens at minimum 1 per 10 CY; flow per ASTM C939.

• PU foam injection (Avanti AV-202 or equal) for slab lifting and soil void filling.
• Chemical grout (acrylate or PU) for water-stopping and soil consolidation.
• Curtain grouting: inject into soil or rock to form vertical water-stopping curtain.

• Expanding PU foam injection under settled slabs to restore grade.
• Mark drill hole pattern; drill 1"–2" holes at specified spacing.
• Inject foam until slab reaches target elevation; patch all holes after completion.

• Grout take log per hole: volume, pressure, and refusal criteria documented.
• Post-injection GPR rescan or probe drilling to verify void fill.
• Slab elevation survey before and after lifting to document results.