Xypex: Concrete Waterproofing by Crystallization™

Xypex is a non-toxic, chemical treatment for the waterproofing and protection of concrete. Xypex's primary and most distinguishing performance feature is its unique ability to generate a non-soluble crystalline formation deep within the pores and capillary tracts of the concrete - a crystalline structure that permanently seals the concrete against the penetration of water and other liquids from any direction. Xypex crystalline products are dry powder compounds composed of portland cement, silica sand and many active, proprietary chemicals.

HOW DOES XYPEX WORK?

To create its crystalline waterproofing effect, Xypex must become an integral part of the concrete mass. It does so by taking advantage of the natural and inherent characteristics of concrete; concrete is both porous (capillary tract system) and chemical in nature. By means of diffusion, the reactive chemicals in Xypex use water as a migrating medium to enter and travel through the capillary tracts in the concrete. This process precipitates a chemical reaction between Xypex, moisture and the natural chemical by-products of cement hydration (calcium hydroxide, mineral salts, mineral oxides and unhydrated and partially hydrated cement particles). The result is crystallization and, ultimately, a non-soluble crystalline structure that plugs the pores and capillary tracts of the concrete. In this condition, the pores become discontinuous and the concrete is thereby rendered impenetrable by water and other liquids from any direction. The Xypex crystalline process will reactivate whenever water is present.

The crystallization process that Xypex causes within the pores and capillary tracts of concrete is illustrated below in electron microscope photos taken by an independent research team.

1. CONCRETE (UNTREATED) A control sample of concrete was sheared through at 50 mm below the top surface. The sheared face shows some of the by-products of cement hydration with which Xypex reacts. Precipitated calcium hydroxide together with cubic and rhombic particles are visible.

BASIC USE

>XYPEX is a unique chemical treatment for the waterproofing and protection of concrete. Among its many uses, XYPEX is suitable for waterproofing reservoirs, sewage and water treatment tanks, tunnels, manholes, underground vaults, foundation walls and parking decks. It can be used on either poured-in-place concrete or concrete block and can be applied to either the interior or exterior surface with equal results.

HOW LONG DOES XYPEX LAST?

A Xypex application, unlike most other systems, is permanent. Its unique, dendritic crystalline growth will not deteriorate under normal conditions.

DOES XYPEX PROTECT REINFORCING STEEL?

Yes. By preventing the intrusion of chemicals, salt water, sewage and other harmful materials, Xypex protects concrete and reinforcing steel from deterioration and oxidation.

CHARACTERISTICS

XYPEX waterproofs underground structures from the inside against hydrostatic pressure. By the process of diffusion and because the chemicals in XYPEX have an affinity with water, the crystalline formation migrates throughout the pores and capillary tracts of concrete even against strong hydrostatic pressure.

XYPEX protects concrete and reinforcing steel. The XYPEX treatment is highly resistant to most aggressive substances, pH 3 - 11 constant contact, pH 2 - 12 periodic contact. By preventing the intrusion of chemicals, salt water, sewage and other harmful materials, XYPEX protects concrete and reinforcing steel from deterioration and oxidation. The concrete is also protected against spalling, efflorescence, popouts and other damages caused by weathering, bleeding of the salts and internal expansion and contraction during the freeze/thaw cycle. XYPEX permits concrete to breathe. The XYPEX crystalline formation has fixed-size air spaces so small that water cannot pass through. It does allow the passage of air and vapor, thus the concrete is able to breathe and become thoroughly dry, preventing moisture vapor build-up. XYPEX products are nontoxic. They have been approved by NSF International, US Environmental Protection Agency, Agriculture Canada and many other government health agencies throughout the world for use on concrete structures that hold potable water or are in contact with foodstuffs.

ADVANTAGES

• Not just a surface coating - Not dependent upon continuity of membrane for     water proofing action
• Seals hairline cracks up to 1/64 in. (0.4 mm)
• No surface priming or leveling required
• Cannot puncture, tear or come apart at the seams
• Does not require protection during back-filling or during placement of     steel, wire mesh or other materials
• Can be applied to moist or green concrete
• Less costly to apply than most other waterproofing methods

COMPOSTION & MATERIALS

XYPEX is manufactured in the form of a dry powder compound consisting of portland cement, very fine treated silica sand and various active proprietary chemicals. When mixed with water and applied as a cementitious coating, the active chemicals in XYPEX cause a catalytic reaction which generates a nonsoluble crystalline formation of dendritic fibers within the pores and capillary tracts of concrete. Thus, the concrete itself becomes permanently sealed against the penetration of water or liquids from any direction.

TYPES

XYPEX crystalline waterproofing technology is available in three forms:

• As a coating - for new or existing structures
• As an admixture - included in the concrete mix at the time of batching
• As a dry shake material - for new horizontal surfaces

XYPEX CONCENTRATE

Used as a single coating on above or below-grade concrete, or as the first of a 2 coat application where two coats are required. See XYPEX Specification Manual. Also used as a Dry-Pac for sealing construction joints and for repair of cracks, faulty construction joints and honeycombing. XYPEX CONCENTRATE is the most chemically potent of the XYPEX crystalline waterproofing materials.

XYPEX PATCH'N PLUG 

Fast setting, nonshrink, high-bond-strength hydraulic cement compound for concrete repairs. Stops flowing water in seconds. Patch'n Plug seals cracks and tie holes. It is also used for the general repair or patching of concrete. PATCH'N PLUG can be used in conjunction with XYCRYLIC-ADMIX to increase the compressive strength and bond strength of existing concrete.

. TECHNICAL DATA

APPLICABLE STANDARDS

Army Corps of Engineers (USACE) CRD-C 48-73 - Permeability of Concrete
DIN 1048 - Impermeability to Water.
NORM B 3303 - Impermeability to Water
American Society for Testing Materials (ASTM)

• ASTM C 267 - Chemical Resistance of Mortars, Grouts and Monolithic     Surfacings
• ASTM C 672 - Standard Test Method for Scaling Resistance to Concrete     Surfaces Exposed to De-icing Chemicals

JIS A 6204 (Japan) - Freeze/Thaw Durability
USA Standard N6.9-1967
XYPEX Specification Manual.

APPROVALS

Approved for use in structures containing foodstuffs or potable water by:

• NSF International - NSF 61 potable water approval
• US Environmental Protection Agency
• Agriculture Canada
• Contact manufacturer for additional international approvals information.

PHYSICAL/CHEMICAL PROPERTIES

PERMEABILITY

USACE CRD C48-73 Two inch (51 mm) thick, 2000 psi (13.8 MPa), XYPEX-treated, concrete samples were pressure tested up to a 405 ft. (124 m) water head (175 psi / 1.2 MPa) which was the limit of the testing apparatus. While untreated samples showed marked leakage, the XYPEX-treated samples (as a result of the crystallization process) became totally sealed and exhibited no measurable leakage.
DIN 1048 Twenty cm thick XYPEX-treated concrete samples were pressure tested up to 7 bars (230 ft. / 70 m water head) for 24 hours to determine water impermeability. While the reference specimens measured water penetration up to a depth of 92 mm, XYPEX-treated samples measured water penetration of zero to an average of 4 mm.
NORM B 3303 XYPEX-treated concrete samples were pressure tested to a maximum 7 bars (230 ft. / 70 m water head) for 10 days. Test revealed that while 25 ml of water had penetrated the untreated concrete samples, zero ml had penetrated the XYPEX-treated samples. Test specimens were then broken and showed water penetration to a depth of 15 mm on untreated samples but no measurable water penetration on the XYPEX-treated samples.

CHEMICAL RESISTANCE

ASTM C 267 XYPEX-treated cylinders and untreated cylinders were exposed to hydrochloric acid, caustic soda, toluene, mineral oil, ethylene glycol, pool chlorine, brake fluid and other chemicals. Results indicated that chemical exposure did not have any detrimental effects on the XYPEX coating. Tests following chemical exposure measured an average 17% higher compressive strength in the XYPEX-treated specimens over the untreated control samples.

MAINTENANCE

When properly installed by an applicator experienced in the installation of crystalline waterproofing, XYPEX is permanent and requires no maintenance.

HOW DEEP DOES THE XYPEX CRYSTALLINE FORMATION PENETRATE THE CONCRETE?

The Xypex chemical reactions that initially take place at the concrete surface or immediately adjacent areas, will continue deep into the concrete structure. Independent testing measured the depth of Xypex crystalline penetration into a cast-in-place concrete block at 30 cm (approximately 12 inches). The test concrete sample was coated on the top surface with Xypex Concentrate and left outside the research laboratory in ambient conditions for 12 months.

IS XYPEX TOXIC?
No. Xypex contains no volatile organic carriers (VOC) and can be applied safely in enclosed surroundings. Xypex is approved by numerous country and state health and waterworks departments for use on structures which contain potable water or foodstuffs. A few of these agencies are listed below:

• NSF International
• >Swiss Federal Health Service
• Japanese Food Research Laboratories
• United Kingdom Drinking Water Inspectorate (DWI)
• Singapore Institute of Standards and Industrial Research
• Australian Water Quality Centre
• Slovak Ministry of Health

CAN XYPEX BE APPLIED AGAINST EXTREME HYDROSTATIC PRESSURE? 

Yes. Because Xypex is not dependent upon adhesion to the concrete surface and instead becomes an integral part of the concrete mass through crystallization, it is capable of resisting extreme hydrostatic pressure from either side (positive or negative) of the concrete.

CAN XYPEX BE APPLIED WHILE THE CONCRETE IS WET? 

Yes. In fact, the concrete must be wet or moist before applying the Xypex slurry coat. Xypex requires moisture to generate the crystalline growth in the concrete. The presence of moisture is also necessary to ensure proper bonding of the slurry coat to the surface.

IS XYPEX USED TO WATERPROOF CRACKS, JOINTS AND OTHER DEFECTS IN CONCRETE? 

Yes. Xypex has a specific repair system that utilizes its unique crystalline waterproofing technology to stop water flow through cracks, faulty joints and other defects. In the case of expansion joints or chronic moving cracks, a flexible sealant is recommended.

WHAT ARE SOME TYPICAL XYPEX APPLICATIONS? 

Typical Xypex applications include reservoirs, sewage and water treatment tanks, secondary containment structures, tunnels, underground vaults, foundations, parking structures, swimming pools, and below grade construction.

HOW IS XYPEX DIFFERENT FROM OTHER PRODUCTS? 

The Xypex crystalline system for concrete waterproofing is substantially different from traditional barrier products (membranes, cementitious coatings):

1. Xypex creates a crystalline structure deep within the pores and capillary     tracts of the concrete mass to prevent the penetration of water and     aggressive chemicals. In contrast, barrier-type products function only at     the surface of the concrete.
2. Because Xypex is not dependent on surface adhesion to achieve its     waterproofing effect, it is resistant to extreme hydrostatic pressure.
3. Xypex will seal hairline cracks up to 1/64 inch (0.4 mm).
4. Xypex is not subject to the deterioration problems encountered by     membranes.
5. Xypex is permanent and reactivates whenever water is present.