Abstract: Resin-based structures for use in corrosive environments. The resin-based structures may include a mixture of resin and aggregate. The resin-based structures may be formed in a mold by placing aggregate and resin into the mold. The resin-based structures may have thin wall design with high compression and tension strength.

Abstract: A new inner passageway through a pre-cast concrete structure damaged by corrosion may be formed by stackable inserts formed of polymer concrete. The inserts may be stacked in the old passageway through the pre-cast concrete structure such that an inner surface of the stacked inserts forms a new passageway through the pre-cast concrete structure. A grout may be poured between an outer surface of the stacked inserts and an inner surface of the pre-cast concrete structure forming the old passageway. The surfaces of the stackable inserts may have superior resistance to corrosive acids such that the need for future repair is greatly reduced. Suitable pre-cast concrete structures for rehabilitation include pre-cast concrete structures utilized in wastewater systems, including manholes and other similar structures. In this manner, the damaged pre-cast concrete structures do not need to be removed during the rehabilitation.

Abstract: Resin-based structures for use in corrosive environments. The resin-based structures may include a mixture of resin and aggregate. The resin-based structures may be formed in a mold by placing aggregate and resin into the mold. The resin-based structures may have thin wall design with high compression and tension strength.

Abstract: A polymer manhole base may comprise a base portion having an upper surface. An annular sidewall may extend upward from the base portion and may circumscribe the upper surface. The manhole base may have a wastewater trough connecting a wastewater inlet and a wastewater outlet. An interior frame may correspond to the inlet or outlet.

Abstract: A polymer manhole base comprising a base portion having an upper surface. An annular sidewall may extend upward from the base portion and may circumscribing the upper surface. The annular sidewall may have a diameter. A thickness of the annular sidewall may less than 1/12th of the diameter.

Abstract: A new inner passageway through a pre-cast concrete structure damaged by corrosion may be formed by stackable inserts formed of polymer concrete. The inserts may be stacked in the old passageway through the pre-cast concrete structure such that an inner surface of the stacked inserts forms a new passageway through the pre-cast concrete structure. A grout may be poured between an outer surface of the stacked inserts and an inner surface of the pre-cast concrete structure forming the old passageway. The surfaces of the stackable inserts may have superior resistance to corrosive acids such that the need for future repair is greatly reduced. Suitable pre-cast concrete structures for rehabilitation include pre-cast concrete structures utilized in wastewater systems, including manholes and other similar structures. In this manner, the damaged pre-cast concrete structures do not need to be removed during the rehabilitation.

Abstract: Resin-based structures for use in corrosive environments. The resin-based structures may include a mixture of resin and aggregate. The resin-based structures may be formed in a mold by placing aggregate and resin into the mold. The resin-based structures may have thin wall design with high compression and tension strength.

Abstract: A centering device between two adjacent tubular members, such as pre-cast concrete structures used in a manhole assembly, may comprise a guide member having a sidewall and a crosspiece member. The guide member may be installed on an end of a first tubular member. The second tubular member may be stacked on top of the first tubular member. The guide member may center the first and second tubular members and may prevent horizontal displacement of the first tubular member with respect to the second tubular member.