Method and apparatus for sewer and manhold repair

Abstract

A complete system and method can be used for the repair and sealing of a sewer manhole. The process of the present invention includes surface preparation with steps to purge out embedded contaminants, application of a primer to the prepared and purged surface, application of a closed cell foam layer over the primer layer, and application of polyurea layer disposed on the foam layer. By first making sure the concrete is purged of contaminants, the system, when applied, cannot be damaged by the outgassing of contaminants from the coated concrete as may be possible with conventional systems. Moreover, the system of the present invention uses a 100% polyurea coating that provides appropriate flexibility, strength, and chemical resistance.

Description

BACKGROUND OF THE INVENTION[0001]The present invention relates to systems and methods for repair of concrete-based systems, and more particularly, to systems and methods that can be applied to repair and renew sewers, manholes and the like.[0002]Afflicted by pipe failures, sewer backups and sewage spills, America's wastewater infrastructure is clearly showing its age. Most municipal systems are 75 to 100 years old, and nearly all are compromised to some degree by corrosion, overburdening and structural fatigue. Even as these existing systems are deteriorating, population demands are pressing upon cities to expand their wastewater collection capabilities.[0003]More and more municipalities are addressing this growing health and environmental challenge by paying increased attention to rehabilitating corroded manholes. By most industry estimates, leaking manholes account for an estimated 20% to 30% of the unnecessary groundwater infiltration and inflow that overtax and threaten the sani...

AI Technical Summary

Benefits of technology

The present invention provides coating and repair systems for concrete or brick surfaces that have excellent properties including high durability, flexibility, and resistance to cracking and corrosion. The systems comprise a surface preparation material, a primer layer, a foam layer, and a polyurea layer. The repair system also includes applying a purge treatment, a primer layer, a foam layer, and a polyurea layer to manholes. These systems and methods utilize the benefits of foam layers, namely their ability to absorb impact and flex, and the strength and durability of polyurea layers, to provide superior protection and repair for concrete and brick surfaces.

Problems solved by technology

Most municipal systems are 75 to 100 years old, and nearly all are compromised to some degree by corrosion, overburdening and structural fatigue.

Even as these existing systems are deteriorating, population demands are pressing upon cities to expand their wastewater collection capabilities.

Sulfuric acid is highly corrosive to concrete, steel and non-ferrous metals.

When concentrated and heated by summer temperatures, it is extremely damaging to the concrete and non-ferrous metals used in most wastewater structures.

Construction materials in such environments quickly lose their ability to support loads, maintain their shape, transport liquids and function as designed.

Manholes may be among the toughest environments encountered.

The current spray-applied systems suffer from various issues, such as moisture, delamination, shrinkage and structural weakness problems resulting from the typical environment encountered in the repair operation.

The conventional systems often do not achieve good bonding to the manhole substrate.

The conventional systems often do not purge the concrete for correct substrate preparation.

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