Friday, March 22, 2013


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 surfaces and become an integral part of a substrate.

Cementitious systems are excellent materials for use with civil and infrastructure projects, both above and below-grade, using both positive and negative applications. These projects generally consist of large concrete components that make the same generic composition 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
● Swimming pools
● Cooling tower basins

In new construction, where costs and scheduling are critical, these systems are particularly effective. They do not require a completely dry substrate, and concrete does not need to be fully cured before application. This eliminates well pointing and the need for water control during construction. These systems apply to both walls and floors at one time, thereby eliminating staging of waterproofing operations. No subslabs are required for horizontal applications in new construction preventative waterproofing installations.

Finally, in cases such as elevator pits, the waterproofing is completed almost any time during construction as best fits scheduling.

All cementitious systems are similar in application and performance but repel water differently by the proprietary additives of a manufacturer’s formulations. Cementitious systems have several mutual advantages, including seamless application after which no protection board installation is necessary.

All cementitious materials lack crack bridging or elastomeric properties but are successfully applied to below-grade areas that do not experience thermal movement. However, below-grade areas are subject to freeze-thaw cycling and structural settlement. If these cause movement or cracking, a cementitious system will crack, allowing water infiltration.

⇒ Metallic systems   Metallic materials contain a mixture of sand and cement with finely graded iron aggregate or filings. When mixed with water to form a slurry for application, the water acts as an agent permitting the iron filings to oxidize. These materials expand...

⇒ Capillary/crystalline systems   Capillary/crystalline systems are mixtures of cement and sand in combination with proprietary chemical derivatives in dry or liquid form. The systems are applied in trowel, brush, or spray applications. Unlike other cementitious systems however...

⇒Chemical additive systems  Chemical cementitious systems are a mixture of sand, cement, and proprietary chemicals (inorganic or organic), which when applied to masonry or concrete substrates provide a watertight substrate by chemical action. Proprietary chemicals...

⇒ Acrylic modified systems   Acrylic modified cementitious systems add acrylic emulsions to a basic cement-and-sand mixture. These acrylics add waterproofing characteristics and properties to in-place materials. Acrylic systems are applied in two trowel applications, with a reinforcing...

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