Product Data Sheet
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Sikasil®-728 RCS

Sikasil®-728 RCS

Two-part, self-leveling, rapid cure, ultra low modulus, horizontal application, neutral cure silicone sealant

Sikasil®-728 RCS (Rapid Cure System) is a self-leveling, two-component, very rapid cure, ultra low modulus elastomeric, neutral cure silicone sealant. Exceeds the requirements of ASTM C-920, Type M, Grade P, Class 100/50, Use T, M, G, A, O; TT-S-00227E, Type I, and various AASHTO reports and state DOT approvals.

  • No tooling, less labor
  • Excellent flexibility for extreme high and low temperature conditions
  • Excellent flexibility for dynamic joint movement
  • Bonds to most substrates without priming
  • Open to traffic in one hour
  • All season ease of application
  • Good contact/adhesion with hard to reach areas
  • Ideal for cold climates
  • Excellent for use on runways and tarmacs
  • Jet fuel resistant
  • Resistant to road salts
Product Data Sheet
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Usage

Construction Application
  • Horizontal expansion joints
  • Highway and bridge joints
  • Saw cut joints - new and remedial
  • Plaza decks
  • Parking decks
  • Bridges
  • Airports
  • Stadiums
  • Driveways
Location
  • Horizontal
  • Interior and exterior
  • Above grade or on grade
Substrate
  • Concrete, steel, glass, aluminum, tile, ceramic, masonry, brick, stone and granite
 

Advantages

  • No tooling, less labor
  • Excellent flexibility for extreme high and low temperature conditions
  • Excellent flexibility for dynamic joint movement
  • Bonds to most substrates without priming
  • Open to traffic in one hour
  • All season ease of application
  • Good contact/adhesion with hard to reach areas
  • Ideal for cold climates
  • Excellent for use on runways and tarmacs
  • Jet fuel resistant
  • Resistant to road salts

Packaging

40 fl. oz. unit - 2 20 oz. sausages/20 per case;

9 gal. unit (34.11 L) – 2 pails each containing 4.5 gal. (17 L);

104 gal. unit (394.16 L) –2 drums each containing 52 gal. (197.08 L)

Color

Limestone and Charcoal Gray (when Part A, dark gray and Part B, white, are mixed).

Product Details

Product Information

Shelf Life

When stored in the original, unopened containers at or below 90 °F (32 °C), shelf life is one year. A product skin may form in pails and drums, remove prior to use

Storage Conditions

Store in unopened containers at temperatures at or below 90 °F (32 °C)

Volatile organic compound (VOC) content

2.4 % by wt., 30 g/l, 0.25 lb./gal
Technical Information

Shore Hardness

50 ± 5

Shore OO

4 - 6

Shore A

Tensile Strength

70 psi (0.48 MPa)

(7 days, at 77 °F (25 °C) and 50 % R.H.) (ASTM D-412)

Secant Tensile Modulus

5

(7 days, at 77 °F (25 °C) and 50 % R.H.) (ASTM D-5329 [a] [b])

(100 % elongation)

Tensile stress at specified elongation

25 psi (0.17 MPa)

(7 days, at 100 % and 77 °F (25 °C) and 50 % R.H.) (ASTM D-412)

Elongation

725 %(7 days, at 77 °F (25 °C) and 50 % R.H.) (ASTM D-5329 [a] [b])

Adhesion in peel

30 pli

(7 days, at 77 °F (25 °C) and 50 % R.H.) 

(glass, aluminum and concrete) (ASTM C-794)

Movement Capability

+100 %, -50 %

(7 days, at 77 °F (25 °C) and 50 % R.H.) (ASTM C-719)

(glass, aluminum and concrete)

Resistance to Weathering

Excellent

Service Temperature

-80–350 °F (-62.2–176.6 °C)

Joint Design

The number of joints and the joint width may be designed for high movement capability. For joints one to three inches in width, the sealant will accept movements +100% and -50% and for three to four inches in width, the sealant will accept movements of ±50% of joint width at time of installation. The depth of the sealant should be 1/2 the width of the joint. The minimum depth is 1/4 inch (6 mm) and the maximum is 1/2 inch (12 mm). For joints greater than 1 inch (25.4 mm), do not exceed 1/2 inch (6 mm) in depth.

Application

Application Information

Extrusion rate

50 g/min. 1/8” orifice @ 50 psi Specific Gravity 1.25 - 1.35

(ASTM C-1183 modified, Type S)

Backing Material

To control joint depth, use closed cell polyethylene or non-gassing polyolefin backer rod. If joint depth does not allow for backer rod, use polyethylene bond breaker tape to prevent three-sided adhesion. Closed cell backer rod should be 25% larger than joint width; do not compress more than 40%. Never use open cell rod in on grade horizontal joints.

Sag Flow

self-leveling @ 120 °F (49 °C)

(ASTM C-639)

Cure Time

90 % in 1 h

(at 77 °F (25 °C) and 50 % R.H.) (MNA Method)

Skin Time

10 min.

(at 77 °F (25 °C), 50 % R.H.) (MNA Method)

Tack Free Time

25 min.

(at 77 °F (25 °C), 50 % R.H.) (ASTM C-679)
Consumption

Coverage

40 oz Sausage: Yield in Linear feet

Width/Depth1/4''3/8''1/2''
1/4''96.2
3/8''64.242.8
1/2''48.232.024.0
3/4''32.021.416.0
1''12.0
1.25''9.6
1.5''8.0

1 gallon: Yield in Linear feet

Width/Depth1/4''3/8''1/2''
1/4''307.9

3/8''

205.3136.8
1/2''153.9102.677.0
3/4''102.668.451.3
1''38.5
1.25''30.8
1.5''25.7
Application steps

SUBSTRATE PREPARATION

The substrate must be clean, dry, frost free, sound and free of any oils, greases or incompatible sealers, paints or coatings that may interfere with adhesion.

Porous Substrates – clean by mechanical methods to expose a sound surface free of contamination and laitance.
Non-porous substrates – for cleaning non-porous substrates, use two rag wipe method using xylene or an approved commercial solvent. Allow solvent to evaporate prior to sealant application.

Priming

Sikasil-728 RCS is designed to obtain adhesion without the use of a primer; however, best results are obtained when horizontal joints are primed. Test by applying the sealant and/or primer sealant combination to confirm results and proposed application methods. Refer to Technical Data Sheet for Sikasil Primer and contact Technical Service for additional information.

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