The manhole was inherited by IRWD in extremely poor condition and needed rehabilitation. Although it had been previously lined with another liner system, the substrate was never properly sealed and the existing liner system and the concrete it was designed to protect, were failing comprehensively. The high HS environment had severely corroded the existing concrete, exposing rebar, and ultimately threatening the structural properties of the manhole itself. Zebron Contracting, Inc. removed three 55 gallon drums of concrete waste and debris from what was once the base and riser sections of this single manhole. The structure was rehabilitated to its original specification and lined with Zebron # 386.
The existing liner system is compromised. The concrete substrate behind it has been reduced to powder. From an initial visual inspection, the manhole base appears to still exist in some capacity but it is in fact no more than concrete waste and rubble that was scooped up and removed with a shovel. Three 55 gallon drums of waste were removed from this manhole in similar fashion before the remains of the structure could be high pressure blasted.
Before removing the prior applied liner system, concrete waste and debris, base boards are used to cover the channel to prevent any solids from entering the sewer. After the solid waste is removed the manhole is high pressure blasted at 5000psi to achieve a clean, sound substrate.
The manhole is then restored to its original specification with gunite or hand-applied mortar. The base is reformed and shaped accordingly. The Zebron® method of sewer manhole rehabilitation has been refined and developed since municipalities began rehabilitating manholes in the 1970s.
Certified Installer: Zebron Contracting, Inc.
Product Installed: 1-3mil Zebron Low Temperature Epoxy Primer, 125 mil Zebron #386 polyurethane