Sikaflex® Precast
Sikaflex® Precast is a 1-part, polyurethane, moisture-curing, elastic joint sealant. It provides a waterproof seal between precast elements with good mechanical properties and remains elastic over a wide range of temperatures.
- Movement capability of ±25 % (ASTM C719)
- Good adhesion to concrete
- Good sag flow properties
Usage
Sealing joints for:- Movement and connections between precast elements
- For interior and exterior use
Advantages
- Movement capability of ±25 % (ASTM C719)
- Good adhesion to concrete
- Good sag flow properties
Packaging
600 ml cylindrical foil pack: 20 foil packs per box
Refer to current price list for packaging variations
Colour
Concrete grey PC, white PC, beige PC
Product Details
SUSTAINABILITY
- Conformity with LEED v2009 IEQc 4.1: Low-Emitting Materials - Adhesives and Sealants
APPROVALS / CERTIFICATES
- CE Marking and Declaration of Performance to EN 15651-1 - Sealants for non-structural use in joints in buildings - Facade elements - F-EXT-INT CC
- EN ISO 11600-F Class 25HM, Sikaflex® Precast, SKZ, Test report No. 113665/14-III
- ASTM C920-11 Class 25, Sikaflex Precast, MST, Report No. 1213920-SIKA
Composition
Polyurethane
Shelf life
12 months from date of production
Storage conditions
The product must be stored in original, unopened and undamaged sealed packaging in dry conditions at temperatures between +5 °C and +25 °C. Always refer to packaging.
Density
| ~1,60 kg/l | (ISO 1183-1) |
Product declaration
EN 15651-1: F EXT-INT CC
ISO 1600: F 12.5 E
ASTM C920-11: Class 25
Shore A hardness
| ~38 (after 28 days) | (ISO 868) |
Secant tensile modulus
| ~0,60 N/mm2 at 60 % elongation (+23 °C) | (ISO 8339) |
Elastic recovery
| ~90 % | (ISO 7389) |
Tear propagation resistance
| ~9,5 N/mm | (ISO 34) |
Movement capability
| ± 25 % | (ASTM C 719) |
| ± 20 % | (ISO 9047) |
Service temperature
−40 °C to +70 °C
Joint design
The joint dimensions must be designed to suit the movement capability of the sealant. The joint width must be a minimum of 10 mm and a maximum of 30 mm.
A width to depth ratio of 2:1 must be maintained (for exceptions, see table below).
Typical joint dimensions for joints between concrete elements:
| Joint distance [m] | Min. joint width [mm] | Min. joint depth [mm] |
| 2 | 15 | 10 |
| 4 | 30 | 15 |
All joints must be correctly designed and dimensioned in accordance with the relevant standards and codes of practice before their construction. The basis for calculation of the necessary joint widths are the type of structure, dimensions, technical values of the adjacent building materials, joint sealing material and the specific exposure of the building and the joints.
For larger joints, contact Sika® Technical Services for additional information.
Application
Backing material
Use closed cell, polyethylene foam backing rod
Sag flow
| < 3 mm (20 mm profile, +50 °C ) | (ISO 7390) |
Ambient air temperature
+5 °C min./+50 °C max.
Substrate temperature
+5 °C min./+50 °C max. Minimum +3 °C above dew point temperature
Curing rate
| ~2 mm/24 hours (+23 °C / 50 % r.h.) | (CQP* 049-2) |
* Sika Corporate Quality Procedure
Skinning time
| ~65 minutes (+23 °C / 50 % r.h.) | (CQP 019-1) |
Tooling time
| ~40 minutes (+23 °C / 50 % r.h.) | (CQP 019-2) |
Consumption
| Joint width [mm] | Joint depth [mm] | Joint length [m] per 600 ml |
| 10 | 10 | 6 |
| 15 | 10 | 4 |
| 20 | 10 | 3 |
| 25 | 12 | 2 |
| 30 | 15 | 1,3 |
Consumption depends on the roughness and absorbency of the substrate.
These figures are theoretical and do not allow for any additional material due to surface porosity, surface profile, variations in level or wastage etc.
SUBSTRATE PREPARATION
The substrate must be clean, dry, sound and free from oils, grease, dust, cement laitance and loose or friable particles.
Removal techniques such as wire brushing, grinding, grit blasting or other suitable mechanical tools can be used.
Sikaflex® Precast adheres without primers and/or activators.
For optimum adhesion, joint durability and critical, high performance applications such as joints on multi-storey buildings, highly stressed joints, extreme weather exposure or water immersion / exposure. The following priming and/or pre-treatment procedures must be followed:
Porous substrates
Concrete, aerated concrete and cement based renders, mortars and bricks surfaces must be primed using Sika® Primer-3 N applied by brush.
Before sealing, allow a waiting time of > 30 minutes (< 8 hours).
Note: Primers and activators are adhesion promoters and not an alternative to improve poor preparation / cleaning of the joint surface. Primers also improve the long term adhesion performance of the sealed joint.
Contact Sika® Technical Services for additional information.
MIXING
1-part ready to use
CLEANING OF EQUIPMENT
Clean all tools and application equipment with Sika® Remover-208 immediately after use. Hardened material can only be removed mechanically. For cleaning skin, use Sika® Cleaning Wipes-100.