Page 372 - Construction Waterproofing Handbook

8.32 CHAPTER EIGHT
bonding agents or a bonding agent to be added during mixing. The premixed products
have similar properties: they are high strength (compressive strength usually exceeds
2
5000 lb/in ), fast setting (initial set in less than 30 minutes), applicable to damp substrates,
and nonshrinkable.
Some products are used as negative-side waterproofing systems, whereas others are
used to patch a specific area of leakage. Cementitious materials are used in a variety of
restoration procedures. A typical use is repairing spalled concrete surfaces after repair and
preparation of exposed reinforcing steel.
Cementitious patching systems are also used for concrete overlays to add substrate
strength, patching of honeycomb and other voids, and patching to stop direct water infil-
tration. Cementitious patching systems include:

● High-strength patching compounds
● Hydraulic or hot-patch systems
● Shotcrete or gunite systems
● Overlays

High-strength patching
High-strength patching products are supplied in premixed formulations with integral bond-
ing agents. They are used to patch spalled areas or voids in concrete or masonry to prepare
for waterproofing application, Fig. 8.33. These products contain a variety of proprietary
chemicals and additives to enhance cure time, strength, and shrinkage. High-strength
patching systems require only water for mixing and can be applied in a dry or stiff mix that
allows for vertical patching applications.
Properties of cementitious high-strength mixes vary, and product literature should be
reviewed to make selections meet specific repair conditions. Most important, installation
procedure with all products is to use maximum single-application thickness.
Most products require maximum 1-in layers due to the chemical process that creates
extreme temperatures during curing. If an application is too thick, patches will disbond or
blow off during curing.

Hydraulic cement products
Hydraulic products are frequently referred to as hot patches because of heat generated dur-
ing the curing process. Hydraulic refers to running water, such as water leakage through a

FIGURE 8.33 Patching existing spalled concrete with high-strength grout. (Courtesy of Anti-Hydro)