Page 61 - Construction Waterproofing Handbook

BELOW-GRADE WATERPROOFING 2.25
Positive and negative below-grade systems include

● Cementitious systems
● Fluid-applied membranes
● Sheet-membrane systems
● Hydros clay
● Vapor barriers

CEMENTITIOUS SYSTEMS

Cementitious waterproofing systems contain a base of Portland cement, with or without
sand, and an active waterproofing agent. There are four types of cementitious systems:
metallic, capillary system, chemical additive systems, and acrylic modified systems.
Cementitious systems are effective in both positive and negative applications, as well as in
remedial applications. These systems are brushed or troweled to concrete or masonry sur-
faces and become an integral part of a substrate.
Cementitious systems are excellent materials for use with civil and infrastructure pro-
jects, both above and below-grade, using both positive and negative applications. These
projects generally consist of large concrete components that make the same generic com-
position cementitious systems relatively easy to specify and install without compatibility
problems. Among the types of structures cementitious systems are used for:
● Tunnels
● Underground vaults
● Water reservoirs
● Water and sewage treatment facilities
● Elevator and escalator pits
● Below-grade concrete structures

FIGURE 2.34 Below-grade positive and negative waterproofing details.