Spray‑applied Geopolymer Liners (SAPL/SIPP)

Large‑diameter SAPL/SIPP 36–240 in (round and non‑round).

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At‑a‑glance: diameter and shapes

Capability	Range/Details
Diameter (ID)	36–240 in (project‑specific engineering governs upper range)
Supported shapes	Round, oval/egg, arch, box, and irregular masonry profiles
Typical applications	Stormwater culverts, large‑diameter sewers, outfalls, headwalls, inlets

Introduction and scope

Hinterland Group installs spray‑applied geopolymer liners for large‑diameter stormwater and culvert rehabilitation (trenchless), engineered for round and non‑round conduits with internal diameters from 36 to 240 inches, subject to project access and loading. Geopolymer liners provide a structural or semi‑structural renewal with superior resistance to biogenic sulfuric acid (MIC/H2S) attack and minimal surface disruption compared to dig‑and‑replace.

Where geopolymer SIPP fits

• Host materials: RCP, CMP/multiplate, brick, stone, masonry, and deteriorated concrete structures (headwalls, inlets, catch basins).

• Shapes: round, elliptical/egg, arch, box, horseshoe, and irregular stone/brick tunnels.

• Use cases: capacity restoration, corrosion mitigation, joint/wall loss repair, overtopping damage, and hydraulic smoothing for aging culverts and outfalls.

• Access notes: Per industry guidance, spray‑applied mortars/geopolymers are generally suited to diameters ≥30 in., with feasible reaches of 500–1,000 LF per setup depending on equipment and bypassing.

Diameter and shape ranges we deliver

• Diameter design envelope: 36–240 in. (engineering verification required for the upper range; governed by access, live loads, cover, groundwater, and construction logistics). Industry guidance recognizes spray‑applied mortar/geopolymer rehabilitation for large diameters (≥30 in.).

• Supported shapes: round, oval/egg, arch, box, and irregular masonry profiles; suitability is confirmed during condition assessment, cleaning, and trial thickness verification.

Corrosion performance (MIC/H2S)

• Geopolymer binders exhibit significantly improved acid resistance relative to ordinary Portland cement mortars under sulfuric acid exposure representative of MIC environments. Independent research and industry reviews cite lower permeability and superior acid durability of geopolymer matrices in sewer/wastewater conditions.

• MIC mechanism context: H2S generated under anaerobic conditions oxidizes to sulfuric acid on moist surfaces, rapidly degrading conventional concrete; durable liners and flow management are core mitigation measures.

Approvals and standards we support (project‑dependent)

When an owner requires specific approvals, we specify geopolymer systems that carry relevant third‑party validations. Certificates are provided in submittals and can be requested via our Contact Us.

• WRc Approved geopolymer pipe lining systems (e.g., GeoKrete, GeoSpray).

• DIBt approval for wastewater rehabilitation (e.g., GeoKrete, approval Z‑42.3‑612 announced March 10, 2025).

• NSF/ANSI/CAN 61 options for potable/wet weather cross‑connection risks (e.g., GeoSpray 61).

• In‑development ASTM work item for spray‑applied mortar lining of large‑diameter storm water and sewer systems (WK86042), alongside NASSCO specification guidance.

Design methodology and typical thickness ranges

Final thickness is sealed by the Engineer of Record based on host pipe condition (partially vs. fully deteriorated), geometry, soil/traffic loads, groundwater, corrosion allowance, and construction method (spin‑cast vs. hand spray/trowel). Typical installed ranges are below; values outside these ranges are engineered and verified by mock‑ups and core checks.

Inside diameter band	Structural intent	Typical geopolymer thickness (per pass / total)
36–60 in	Corrosion barrier to semi‑structural	0.50–1.0 in per pass; 0.50–1.5 in total
66–120 in	Semi‑ to fully structural	0.75–1.5 in per pass; 1.0–2.0 in total
126–180 in	Fully structural (geometry‑dependent)	1.0–2.0 in per pass; 1.5–3.0 in total
186–240 in	Fully structural (access‑dependent)	1.5–2.0 in per pass; 2.0–≥3.0 in total

Note: Many geopolymer systems are qualified for application thicknesses of approximately 0.5–3.0 inches per pass; higher totals are achieved in multiple passes with intermediate profiling and QA.

Execution workflow (summary)

• Cleaning and defect prep: high‑pressure water/jetting; infiltration control; surface profiling to sound substrate; CCTV pre‑ and post‑lining.

• Lining: spin‑cast or low‑pressure spray; continuous wet‑film thickness checks; trowel finish where specified.

• Curing and QA/QC: ambient or conditioned curing per manufacturer; coring for thickness/adhesion where required; final CCTV and punch‑list closure.

Case blurbs (related large‑diameter delivery)

• Manatee County, FL — 66‑inch stormwater line rehabilitation: Hinterland restored structural integrity and flow in a critical large‑diameter stormwater asset with trenchless methods, minimizing community disruption.

• Charlotte County, FL — Stormwater collection system rehabilitation: comprehensive cleaning, inspection, and trenchless rehabilitation to re‑establish capacity and extend asset life across multiple segments.

Owner deliverables and submittals

• Material data and approvals (WRc, DIBt, NSF/ANSI 61 as required by project); mix design and application method; curing plan; bypass and traffic control plans.

• Design calculations sealed for geometry and loads; corrosion allowance; thickness justification; QA/QC plan with test locations (cores/hammer soundings), CCTV deliverables in NASSCO PACP format.

Get certificates and specifications

For downloadable approvals, datasheets, and project‑ready specifications, contact our team and reference “Geopolymer — large‑diameter stormwater and culverts (36–240 in).” We will provide product‑specific WRc/DIBt/NSF‑61 documentation and a project submittal package. Contact Hinterland.