Cemgrout Rapid


Cemix® Cemgrout Rapid is a rapid setting, super high early strength, high flow, pourable, structural cementitious grout. Characteristics include super high early strength, high flow, shrinkage compensation, excellent substrate adhesion and durability.

Typical Application / Uses:

Cemix® Cemgrout Rapid may be used for:

  • Rapid setting, super high early strength grouting applications.
  • Cold temperature grouting.
  • Early loading & over coating applications.
  • Anchors, bolts, starters & dowels.
  • Structural bearing pads & base plates.
  • Machine & equipment support.
  • Tank support.
  • Void filling.
  • Precast connections & between precast elements.


  • Super high early strength.
  • Can be loaded or over coated in six (6) hours.
  • High flow.
  • Pourable.
  • One component.
  • Good cold temperature performance.
  • Shrinkage compensated.
  • Very short curing times.
  • High bond strength.
  • Durable.
  • Low chloride ion permeability.
  • Improved abrasion resistance.


Substrate Preparation:

Substrates should be clean & free from all contaminants, loose particles, coatings, curing compounds, dirt, mould, oil etc. Substrates must be sound, rough & dampened to ensure a good bond.

Formwork Preparation:

The area to be grouted must be enclosed with good quality rigid watertight formwork. The formwork should be constructed with enough room to use a grout header box system. The formwork must be able to rigidly confine the Cemix® Cemgrout Rapid until it has set. Treat the formwork with a Cemix® form release agent. Formwork should be flushed out just prior to application.

Header Box & Air Vents:

Where appropriate, use a suitable grout header box delivery system to pour the product into place. Create a head of pressure in the header box to force the grout into place. Keep the header box full of grout at a level well above the finished grout level. Avoid air entrapment by applying from one-side and use suitable air vents to vent air as the grout flows into place.

Movement / Control Joints:

Honour any control joints in the concrete substrate – do not apply product over control joints. Create control joints in the grout as required especially in long thin sections.


Mix whole bags of product. Mix thoroughly for 2 - 3 minutes using a drill & paddle or suitable mechanical grout mixer. If a less fluid consistency is required, less water can be added. More water will increase flow but reduce strengths. Add 2.8L of water to the mixer & then add the product to the water. Add rest of water slowly whilst mixing until the desired consistency is achieved. Typical total water for a pourable consistency is approximately 3.2L per 20kg bag. Use product immediately. This is a fast setting product; do not mix more product than can be mixed, placed & finished in 30 minutes. Use chilled water in hot weather as well as to extend working time slightly in normal ambient temperatures. Use chilled mixing water for deep or larger volume pours.


Saturate the concrete substrate with water just prior to grout application. Avoid water ponding. Typical application depths are from 10mm to 150mm. Pour the Cemix® Cemgrout Rapid into place while the substrate is still damp. Where appropriate, use a suitable header box delivery system and air vents as described above. Application is from one side only completely filling the void & avoiding air entrapment. Rod grout to move & compact as required. Immediately trowel finish as required.


Cure product thoroughly after it has set by keeping it wet & covered for at least 6 - 24hours. Avoid product freezing for at least 6 hours.

Technical Data:

Appearance – Sand/Cement grey powder

Strength (MPa) - 40MPa in 6hours; 50MPa in 24hours; 60MPa in 28days; 3.2L of water.

Application Temp – 1˚C - 25˚C

Yield / Coverage - Approximately 10.7L or 0.0107m3 per 20kg bag.

Bond Strength – >3MPa

Thermal Coeff. Of Exp – 9.0 x 10-6 mm/mm/˚C

Chloride Ion Permeability – <1000 coulombs

Working Time – 30 minutes @ 20˚C

The data shown above reflects typical results based on laboratory testing under controlled conditions. Reasonable variations may occur on site.


Do not apply product onto surfaces less than 1OC and more than 25OC.


Please take note that this is a fast setting product with limited working time.

  • Large/deep volumes of grout can generate excessive heat whilst hardening. This may lead to thermal cracking. For large volume applications consider using Cemix® Structural Repair Flowable.
  • In very hot weather, use chilled mixing water.
  • In very cold weather, use warm mixing water.
  • More mixing water will increase flow but reduce strengths.


Clean all tools with water & brush immediately after use.


This product can be stored in its original packaging in a dry place well sealed for 6months after production. Do not store opened bags.

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