Little or No Corrosion

Concrete manholeIf a manhole is new or experiences little corrosion, portland cement-based mortars, such as Mainstay ML-72 Sprayable Microsilica Restoration Mortar, are suitable by themselves to protect surfaces.

Moderate Corrosion

In need of manhole rehab; moderately corrodedIn manholes that experience moderate corrosion, the use of calcium aluminate cement-based mortars, such as Mainstay ML-CA (pH of 2 or higher) or ML-PF (pH of 1 or higher) Microsilica Restoration Mortars (which feature pure-fused calcium aluminate aggregates), may provide improved performance over portland cement-based mortar as a manhole rehabilitation method.

Severe Corrosion (with a pH less than or equal to 1)

In need of manhole rehab; severely corrodedSevere corrosion in a manhole is best controlled by the Mainstay Composite Liner, which is a manhole restoration method consisting of ML-72 Sprayable Microsilica Restoration Mortar underlayment and a protective barrier coating such as Mainstay DS-4 or DS-5 100% Solids Epoxy Coatings. Because the protective coating provides corrosion resistance, portland cement-based mortars are suitable for use as an underlayment, even in corrosive environments. The Mainstay Composite Liner is a system that combines these two components simultaneously, thereby reducing labor and the number of mobilizations required to perform the work.