Non-Shrink Micro Concrete

A dry ready-mix cementitious-based product called Non-Shrink Micro Concrete was developed for use in repairing and restoring concrete-damaged regions. It can be utilized in situations where it is difficult to pour or install ordinary concrete in the region that needs repair and where movement is restricted. It is a pourable mortar that has been carefully developed for repairs and restoration of damaged or weakened structural concrete elements. It has a high flow, dual shrinkage compensation, and high strength.

Application

When compaction is impossible and access is restricted, non-shrink micro-concrete can be utilized to increase the load bearing capacity of RCC columns by jacketing. This can be done to repair or restore damaged RCC elements like beams, columns, etc.
It has been created and engineered for use in medium- and large-scale repairs and restorations with typical thickness ranges of 5 to 100 mm.
The layers that must be put to this product typically range in thickness from 5mm to 25mm. Depending on the type of repair, the location, the quantity of exposed rebars, and the final formulation of the product created for the customer, greater thickness is also possible.

Benefits

⦁ Consistent performance is assured since the product is formulated, designed and manufactured in the factory controlled environment.
⦁ High initial strength and sustained long term performance and strength.
⦁ This product is Dual Shrinkage Compensated to reduce the risk of cracking.
⦁ Self-flowing and Free Flowing (hence does not require any additional compaction).
⦁ Extremely low permeability to provide maximum protection to the embedded steel reinforcement.
⦁ Strength and Durability Designed to match the parent substrate.

Uses

⦁ Dense reinforcement area where conventional concreting is very difficult.
⦁ For Repairs or Restoration or Rehabilitations or Jacketing of tight/congested RCC Reinforcement.

Method of Application

1. Clean the surface and remove loose concrete, dust, oil, paint, grease, waterproof coating etc.
2. Expose any corroded steel in the repair area and remove all scale and corrosion deposits. Apply Rust Remover for rust free bars.
3. For Cathodic Protection, apply Epoxy Zinc Primer over the cleaned re-bars and allow it to dry before pouring of Non-Shrink Micro Concrete.
4. Saturate the substrate with water to prevent absorption of water from the mixed material.
5. Add around 80% to 85% of the predefined amount of water in the mixing vessel. Start addition of micro concrete powder slowly under continuous mixing, preferably in a paddle mixer or a slow speed mixer. Keep mixing for 2 minutes. Add a balanced quantity of 15%-20% of mixing water and again mix for another 2-3 minutes to form a homogeneous, free flowing uniform and lump-free mix. Allow the mix to rest for 2-3 minutes and then remix for a minute or two before applying.
6. Shuttering has to be water tight to avoid any material loss and abnormal shrinkage or honeycombing.
7. Start the pour immediately and use the material within 20 minutes of mixing. Remove the shuttering preferably after 24-48 hours (depending on weather conditions).
8. Cure the repaired concrete for a minimum 7 days or use a high quality curing compound for curing.

Technical Specification

PROPERTIES	SPECIFICATION	RESULTS
Density		2.23 approx
Working Time		30 mins
Water/Powder ratio		0.16	0.12
*Consistency (W/P @ 0.16)		Fluid	Flowable
Compressive Strength at 1 day 7 days 28 days	BS 4551 : Part 1:1998 ASTM C 109	20 N/mm² min 45 N/mm² min 65 N/mm² min	25 N/mm² min 60 N/mm² min 80 N/mm² min
Flexural Strength at 28 days	BS 6319-3	8 N/mm² min	10 N/mm² min
Tensile Strength at 28 days	BS 6319-7	4 N/mm² min	5 N/mm² min
Water Permeablity	AASHTO T 277	Low
Liner Shrinkage	ASTM C157	<600 microstrains
Water Absorbtion	BS 1881-Part 208	<0.01 m1/m2/sec at 2hrs