Page 365 - Construction Waterproofing Handbook

REMEDIAL WATERPROOFING 8.25

FIGURE 8.21 Cracks must be cleaned and prepped before injection. (Courtesy of
Abatron, Inc.)

Cracks must be sealed with brushable epoxy gel or wax, to prevent epoxy runout dur-
ing injection (Fig. 8.22). Ports should be installed using either surface-mounted or drilled
ports as recommended by the manufacturer.
Injection should begin at the lowest port and be injected until epoxy is visible at the next
higher port (Fig. 8.23). After sealing and capping of the injected port, the injection is then
moved to the next port. Upon completion of port injection, substrate sealers and ports are
removed.
Most epoxy used for injection is two-component, and must be properly mixed before
application. Working life or pot life is extremely limited, and epoxy must be installed
before it begins to cure in the applicator equipment. Epoxy injection equipment that mixes
2
and injects epoxy under constant uniform pressure, approximately 100–300 lb/in , is avail-
able (Fig. 8.24). Low-viscosity epoxy thickens in cool weather and may not flow suffi-
ciently to fill the crack. Hand pump injectors are adequate as long as enough ports are used
(Fig. 8.25).
Upon injection completion, a core sample of substrate and installed epoxy should be
taken. This allows for inspecting penetration depth and testing strength of cured epoxy and
repaired substrate. Epoxy materials are extremely hazardous and flammable. Care should
be taken during their use as well as their disposal. Equipment must be checked frequently
to ensure that proper mixing ratios are being maintained.

CHEMICAL GROUT INJECTION

Epoxy materials are used for restoring substrates to sound structural strength, with water-
proofing of cracks a secondary benefit. Epoxy joints do not allow for movement. If move-
ment should occur again, leakage can resume. Chemical injection grouts, on the other