Non Shrink Grout Application Method Step by Step
Applying non shrink grout correctly is just as important as selecting the right product. Even the best grout can fail if surface preparation, mixing, placement, or curing is done improperly. This step-by-step guide explains the correct non shrink grout application method used on construction sites to ensure full load transfer, dimensional stability, and long-term durability.
Step 1: Understand the Application Requirement
Before starting any grouting work, clearly identify the purpose of the grout.
- Confirm whether the grout is for machinery base, column base, anchor bolts, or structural repair
- Check required compressive strength and grout grade
- Decide on flowable, plastic, or stiff consistency
- Follow engineer or project specifications
Step 2: Surface Preparation
Proper surface preparation is critical for bond and performance.
- Remove dust, oil, grease, laitance, and loose particles
- Roughen smooth concrete surfaces if required
- Ensure anchor bolts and steel surfaces are clean and rust-free
- Blow out debris from pockets and bolt holes
Step 3: Pre-Wetting the Concrete
Pre-wetting prevents water loss from grout into dry concrete.
- Soak concrete surface with clean water before grouting
- Allow surface to become saturated surface dry (SSD)
- Remove standing water before placing grout
Step 4: Formwork Installation
Formwork ensures grout remains confined during placement.
- Install rigid, leak-proof formwork around the grouting area
- Seal all joints using foam, putty, or sealant
- Provide a grout head or funnel to assist flow
- Ensure adequate venting for air escape
Step 5: Mixing the Non Shrink Grout
Correct mixing ensures strength and shrinkage compensation.
- Measure water accurately as per recommended mixing ratio
- Add water into a clean container first
- Gradually add grout powder while mixing
- Mix using a low-speed mechanical mixer for 3–5 minutes
- Achieve uniform, lump-free consistency
Step 6: Placement of Grout
Grout placement must be continuous and controlled.
- Pour grout from one side only to avoid air entrapment
- Allow grout to flow naturally under the base plate
- Do not vibrate the grout
- Use rodding gently only if required
- Maintain continuous flow until the cavity is completely filled
Step 7: Grouting Anchor Bolts and Pockets
Special care is required for anchor bolt applications.
- Ensure bolt holes are clean and free from water
- Use flowable grout for complete filling
- Pour grout slowly to avoid trapping air
- Fill pockets from the bottom upward
Step 8: Finishing the Grout Surface
Proper finishing improves durability and appearance.
- Trim excess grout after initial stiffening
- Avoid overworking the surface
- Ensure edges are sealed and compact
Step 9: Curing of Non Shrink Grout
Curing is essential for strength development.
- Protect grout from rapid moisture loss
- Use wet hessian, curing compound, or plastic sheeting
- Maintain curing for at least 3–7 days
- Avoid exposure to direct sun and wind
Step 10: Loading and Inspection
Grout must reach sufficient strength before loading.
- Do not apply load until required strength is achieved
- Follow recommended loading time from specifications
- Inspect grout for cracks, voids, or leakage
- Rectify defects immediately if found
Common Application Mistakes to Avoid
Avoiding these errors ensures successful grouting.
- Adding extra water to improve flow
- Poor surface preparation
- Leaking formwork
- Interrupted grout placement
- Early loading before strength gain
Best Practices for Long-Term Performance
- Use trained workers for grouting works
- Follow product mixing and application guidelines
- Maintain consistent quality control on site
- Document grouting procedures for future reference
Frequently Asked Questions (FAQ)
1. Can non shrink grout be vibrated?
No, vibration can cause segregation and reduce performance.
2. Should grout be poured from all sides?
No, pour from one side only to prevent air entrapment.
3. Is curing mandatory?
Yes, curing is essential for strength and durability.
4. Can grout be applied in layers?
No, it should be placed continuously in one operation.
5. When can machinery be installed?
Only after grout reaches the specified strength.
Raltro
Raltro is a construction materials knowledge platform focused on practical site execution and correct application methods. By explaining the non shrink grout application process step by step, Raltro helps engineers, contractors, and site teams avoid common mistakes, follow best practices, and achieve strong, durable, and reliable grouting results in real construction conditions.