Polymer Geopolymer Injection & Hydro-Sealing in Polo, IL
Challenge
A residential courtyard flatwork installation in Polo, IL, suffered severe differential settlement across multiple exterior concrete slab joints, creating prominent trip hazards and disrupting surface drainage. System Design Specialist Andrew Sagar conducted a field evaluation and determined that the failure was driven by hydraulic subgrade washout beneath the load-bearing concrete matrix. Unsealed control joints and surface fractures allowed rainwater to penetrate the subbase, systematically eroding fine-grained subgrade soils and creating empty subterranean voids directly under the concrete.
Deprived of uniform continuous base support, unsupported concrete sections sheared along existing joint lines and settled under pedestrian traffic and dead weight. The primary engineering challenge was to fill these sub-slab voids, re-compact the underlying subgrade, and precisely raise the heavy concrete slabs back to a flush elevation without deploying heavy machinery, causing high-impact site disturbance, or adding massive static loads that could trigger secondary subgrade consolidation.
Solution
To restore structural plane alignment without invasive slab replacement or prolonged curing delays, System Design Specialist Andrew Sagar engineered a two-stage lifting and hydro-sealing protocol utilizing PolyLevel® Concrete Leveling and NexusPro® Joint Sealant. Operations Lead Ricky Sigala and field technician Jaylen executed the repair by drilling dime-sized injection ports through the settled courtyard slabs at strategically calculated structural points.
Using specialized injection equipment, the team pumped a high-density, hydrophobic two-part polyurethane foam directly beneath the concrete matrix. As the two-part geopolymer expanded up to fifteen times its liquid volume, it filled subterranean voids, compacted loose surrounding soils, and generated upward hydraulic force that raised the concrete slabs flush with adjacent surfaces. Following elevation monitoring to ensure exact alignment across all seams, the team thoroughly cleaned open joints and applied UV-resistant NexusPro silicone joint sealant along every seam, establishing a durable, water-tight barrier against seasonal thermal expansion and future water infiltration. The crew then patched the injection ports with matching cementitious grout, completely eliminating trip hazards and leaving behind a stabilized, fully functional courtyard ready for immediate foot traffic.
