Grouting is an important construction process that helps increase structural integrity, stability and durability. It is the process of injecting a pumpable pasty material into the structure to improve its physical characteristics. The industry has numerous grouting processes; however, cement grouting is one of the most common and efficient methods. This blog will explain what cement grout is, its application, and its process. It will provide you with a clear understanding of whether this grouting will solve your construction needs.
What is Cement Grout?
Cement is one of the most commonly used grouting materials to stabilise the soil and level the structure. Cement grouting is the process of injecting a mixture of cement, sand, and water into the structure’s gaps, cracks, and voids. These are effective repair techniques for structural concrete members and masonry walls. It is also used for hydro structures to prevent water infiltration and potential leakages.
Properties of Cement Grout
Fineness
The cement used for the grouting process should be free from lumps and should be well grounded. Good quality cement should be fine enough to make it more workable when mixed with water and other aggregates.
Soundness
The prepared cement grout should not shrink upon hardening, as it could lead to poor sealing in the cracks and further deterioration.
Consistency
The cement, sand, water, and other additives used in the grout should be mixed in proportion to bring the grout to a proper paste consistency to seal the gaps in the structure effectively.
Compressive Strength
A sample of cement grout should be tested at equal intervals after one to three days of the setting time, during which the compressive strength of the cement grout should be increased.
Setting time
The cement grout used for construction and repair should harden when mixed with water. The initial setting time of the cement grout should not be too short, and the final setting time should not be too long.
Application of Cement Grout
- Cement grouting can be performed when the cracks are dormant.
- They can be used to treat honeycombing in concrete structures.
- The cement mixture fills the hollow or void portion of the masonry works.
- These are ideal for repairing deep-leached mortar joints.
- They can be used to bind the old and new concrete structures.
- They can repair shrunken slabs by injecting the cement grout and raising the slab height hydraulically.
- They can repair foundations by drilling a deep hole and injecting the cement through mud-pumping.
- They can reinforce existing structures, such as walls, floors, beams, slabs, etc.
- The cement grout can be used to fill the gaps between the tiles.
How to Apply Cement Grout?
Here is a step-by-step procedure to apply cement grout to repair cracks in the concrete structure.
- Drill holes in the structure along the cracks and in and around the hollow spots. If there are too many cracks, the holes can be drilled at 500 mm to 750 mm spacings in both directions around the area to be grouted.
- Use galvanised iron pieces (GI Pieces) of 20 mm x 200 mm with one end threaded or fix them to PVC nozzles in the holes with rich cement mortar.
- All the cracks and the annular space around the GI pipes are sealed using cement mortar.
- All the cracks should be cut open to a ‘V’ shaped groove, cleaned, and sealed with rich cement mortar.
- To saturate the masonry, the grout holes should be injected with water a day before the grouting. All the holes are plugged with wooded plugs or locked PVC nozzles. The bottommost plug and two adjacent plugs are removed, and water should be injected into the bottom hole with pressure.
- Check for water coming through the adjacent holes and repeat the process until all the holes are covered.
- While grouting, the same process is repeated; however, the cement grout is injected into the holes.
- The prepared grout should be fully stirred under pressure to avoid setting.
- The grouting is carried out until the cement paste covers all the adjacent holes.
- After grouting, curing should be done for 14 days for the structure to achieve full efficiency.
Cement Grout Care & Maintenance
Cement grouts are normally sealed after installation to prevent discolouration staining and keep the moisture out. This makes it easier to clean the cement grout. However, the cement grout needs regular inspection and cleaning. Using a mixture of water and mild detergent and cleaning the surface regularly could prevent the structure from developing further cracks.
Conclusion
Cement grouting is an efficient and cost-effective way to prevent the existing structure from causing further deterioration. The grouting can fix the pre-existing structures’ cracks, holes, water infiltration, and hydraulic lifting. Although this process seems easy, drilling holes and injecting grouts require skilled labourers to restore the maximum efficiency of the structure. After grouting, proper cleaning and maintenance will help prevent the building from further damage.