Sikacrete®-421 CI Rapid

One-component, early strength-gaining concrete containing factory blended coarse aggregate

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Sikacrete®-421 CI Rapid is a one-component, early strength-gaining concrete containing factory blended coarse aggregate. This concrete is air entrained and also contains a migrating corrosion inhibitor.

High early strength
Fast-setting
Integral corrosion inhibitor
Prepackaged coarse aggregate: Eliminates need to extend material in the field; Eliminates the risk of reactive aggregate
Excellent workability and finishing characteristics
Rapid hardening as defined by ASTM C-928 (Type R3)

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Product Data Sheet Show all documents

Usage

Full depth repairs
On grade, above, and below grade on concrete
On horizontal surfaces
Vertical and overhead surfaces when formed and pumped or poured
As a structural repair material for parking facilities, industrial plants, walkways, bridges, tunnels, dams and balconies
Filler for voids and cavities

Advantages

High early strength
Fast-setting
Integral corrosion inhibitor
Prepackaged coarse aggregate: Eliminates need to extend material in the field; Eliminates the risk of reactive aggregate
Excellent workability and finishing characteristics
Rapid hardening as defined by ASTM C-928 (Type R3)

Packaging

65 lb (29 kg) bag

Color

Gray powder

Product Details

Product Information

Shelf Life

12 months from date of production if stored properly in original, unopened and undamaged sealed packaging

Storage Conditions

Store dry at 40–95 °F (4–35 °C).

Protect from moisture. If damp, discard material

Technical Information

Compressive Strength

2 hours	3,000 psi (20.7 MPa)
1 day	5,000 psi (34.5 MPa)
7 days	6,000 psi (41.4 MPa)
28 days	6,500 psi (44.8 MPa)

Flexural Strength

28 days

1,000 psi (6.9 MPa)

Splitting Tensile Strength

28 days

650 psi (4.5 MPa)

Shear Strength

1 day	1,700 psi (11.7 MPa)
7 days	2,300 psi (15.9 MPa)
28 days	3,000 psi (20.7 MPa)

* Mortar scrubbed into substrate (73 °F (23 °C) and 50 % R.H.)

Shrinkage

Water Cured	0.012 %
Air Cured	-0.016 %

28 days results at 73 °F (23 °C) and 50 % R.H.

Freeze-Thaw Stability

300 cycles

> 90 %

Rapid Chloride Permeability

28 days

600 (Very Low)

Application

Application Information

Mixing Ratio

5.5-6 pints (2.6-2.8 L)

Layer Thickness

Min.	Max.
1" (25 mm)	8" (203 mm)

Product Temperature

65–75 °F (18–24 °C)

Ambient Air Temperature

> 40 °F (4 °C)

Substrate Temperature

> 40 °F (4 °C)

Consumption

Coverage

0.5 ft³(0.01 m³)per bag

(Coverage figures do not include allowance for surface profile and porosity or material waste)

Application steps

MIXING

Start mixing with 5.5 pints (2.6 L) of water.
An additional 0.5 pint (0.2 L) can be added if needed.
Do not overwater as excess water will cause segregation.
Add Sikacrete®-421 CI Rapid while continuing to mix. Mix to a uniform consistency, maximum 3 minutes. Mechanically mix with a low-speed drill (400–600 rpm) and paddle or in appropriate-size mortar mixer or concrete mixer.

APPLICATION

Pre-wet surface to SSD.
Ensure good intimate contact with the substrate is achieved. To accomplish this, material should be scrubbed into the substrate or other suitable means should be employed such as vibration of the material or pumping under pressure.
Vibrate form while pouring or pumping.
Pump with a variable pressure pump.
Continue pumping until a 3 to 5 psi increase in normal line pressure is evident then STOP pumping.
Form should not deflect.
Vent to be capped when steady flow is evident, and forms stripped when appropriate.

CURING TREATMENT

As per ACI recommendations for Portland cement concrete, curing is required.
Moist cure with wet burlap and polyethylene, a fine mist of water or a water based* compatible curing compound.
Curing compounds adversely affect the adhesion of following lifts of mortar, leveling mortar or protective coatings.
Moist curing should commence immediately after finishing. Protect freshly applied mortar from direct sunlight, wind, rain and frost.

* Pretesting of curing compound is recommended.