Batimix Concrete 520

Description

BATIMIX Concrete 520 is a pre-packed self-consolidating concrete repair material. It has high flowability and moderate viscosity, which are required to ensure homogenous deformation. It is made of Portland cement Type I, silica fume, fillers, carefully-graded fine and coarse aggregates, and selected plasticizing, viscosity-enhancing, and shrinkage-compensating agents. Used for repairing cracks, holes, and other structural flaws, this pre-packaged mixture ensures strong adhesion, proper curing, and durability, simplifying the process of restoring existing concrete structures such as pavements, floors, bridges, and facades. It offers effective bonding with the original concrete, strength to withstand loads and environmental conditions, and a consistent finish, making it a versatile solution for both minor and major repairs while minimizing construction disruptions.

Main Purpose

BATIMIX Concrete 520 flows under its own weight. It requires no vibration during the casting process. It is used for partial and full-depth repair and rehabilitation of beams, columns, slabs, parking structures, garages, bridge decks, reservoirs, and other concrete structures.BATIMIX Concrete 520 is particularly recommended for use in areas difficult to access, complex architectural shapes, and/or a congested degree of reinforcing bars.

Features

BATIMIX Concrete 520 has the following characteristics:

• Similar properties to conventional concrete, thus ensuring excellent compatibility with parent concrete substrate
• Simplification of the concrete placement as no vibration is required
• Increase of production efficiency and reduction of labors at the job-site
• Minimum bleeding and segregation, despite the high flowability
• Improved dimensional compatibility (shrinkage, expansion, and creep)
• High degree of adhesion/bond to the repaired structure
• Low water absorption, yet increased water vapor transmission
• Improved durability with a high quality finished texture

Properties

• Appearance/color: powder/grey
• Bulk density: around 1.8
• Chloride content: nil
• Grain size: 0 to 10 mm (upon request, this product can be made with smaller maximum aggregate size)
• Yield: approx. 0.022 m³ per bag of 50 kg

Health and Safety

BATIMIX Concrete 520 contains cement and silica fume. In case of contact with the eyes or skin, rinse the contact area immediately with plenty of water. Wear suitable gloves. For further information, refer to the product Material Safety Data Sheet.

Directions for Use

1 – Concrete removal Exposed surfaces to be repaired should be visually inspected and sounded for weakness and delamination. All deteriorated concrete should be removed to a near uniform depth of a minimum 25 mm by suitable means.

2 – Substrate preparation Prior to preparation of substrate surfaces, exposed reinforcing bars should be inspected to ensure the following:

• Appropriate exposure, with a minimum clearance of 20 mm
• Loose reinforcing bars replaced in their original design location
• Proper cross-sectional area, with a maximum reduction of 25%

For optimum bonding, sandblast the concrete and reinforcing bar surfaces and then remove all dust and debris by air blasting, low pressure water blasting, or brooming. If the damage was the result of corrosion, an epoxy coating should be considered. Prior to concreting, the substrate should be saturated but free of standing water (SSD condition).

3 – Formwork If repairs are to be made to vertical or overhead surfaces, formwork will be required. Prior to installing forms, the concrete surface must be inspected for any surface contours that could result in trapped air during concrete placement. Formworks should be designed to withstand the developed concrete lateral pressure; refer to ACI 347 “Formwork for Concrete”.

4 – Product preparation BATIMIX Concrete 520 is primarily formulated to yield high consistency levels corresponding to slump flow of 450 to 600 mm. However, lower consistencies can also be achieved if using lower dosages of water.

A 50-kg bag of BATIMIX Concrete 520 should be mixed with 4.5 to 5.25 liters of clean water, depending on the desired slump flow consistency (see Table below). The mixing should be done with a medium-speed mechanical mixer for a minimum of 3 minutes until obtaining a consistent homogenous material.

5 – Concrete placement Do not place BATIMIX Concrete 520 when ambient temperature is below 5 °C or higher than 35 °C; refer to ACI 306R “Cold Weather Concreting” and ACI 305 “Hot Weather Concreting”. In warm weather, cold water can be used to cool concrete temperature and prevent rapid workability loss.

BATIMIX Concrete 520 can be placed by pumping or cast-in-place using buckets. Depending on the consistency level, BATIMIX Concrete 520 may or may not need any compaction during placement in the forms. For example, little or no vibration is needed for a 450 or 600-mm slump flow concrete, respectively. It remains to the concrete foreman on the site to determine the proper consolidation means for optimum forms filling with respect to the concrete consistency.

6 – Curing Freshly deposited BATIMIX Concrete 520 must be protected from excessively hot or cold temperatures and maintained with minimum moisture loss; refer to ACI 308 “Practice for Curing Concrete”. Curing should begin immediately after the finishing operations and continue for a minimum of 7 days.

Curing of BATIMIX Concrete 520 can be done using absorptive mats which are kept continuously wet. Alternatively, appropriate sheet materials or curing compounds conforming to ASTM C 171 / C 309 can be used.

Physical Properties

| ASTM Test Method | BATIMIX Concrete 520 Results | | --------------------------------------------------- | ---------------------------- | | Water per 50-kg bag, liters | 4.5 -5 | | Initial slump (C143), mm | 450 x 450 | | Fresh wet density (C138), kg/m³ | 2,325 | | Air content (C231), % | 2.3 | | Average setting time (C403), hours | 9 - 12 | | Compressive strength after 1 and 28 days (C39), MPa | 7 and 45 | | Flexural strength after 7 and 28 days (C78), MPa | 6.3 and 8.1 | | Adhesion to substrate (D4541), MPa | > |

| ASTM Test Method | BATIMIX Concrete 581 Results | | --------------------------------------------------- | ---------------------------- | | Water per 50-kg bag, liters | 4.75 - 5.25 | | Initial slump (C143), mm | 600 x 600 | | Fresh wet density (C138), kg/m³ | 2,370 | | Air content (C231), % | 2.5 | | Average setting time (C403), hours | 10 - 15 | | Compressive strength after 1 and 28 days (C39), MPa | 6.2 and 42 | | Flexural strength after 7 and 28 days (C78), MPa | 5.6 and 7.7 | | Adhesion to substrate (D4541), MPa | > 3 |

The following data are averages of several tests under laboratory conditions of 23 °C and 50% R.H.; they may significantly vary in the field.

To adapt mixture composition to specific applications and climatic conditions, supplementary admixtures such as set-retarder, set-accelerator, air entrainer, and synthetic fibers may be added to the original mix design.

Storage

BATIMIX Concrete 520 should be stored in a closed and dry place. Avoid freezing and excessive temperatures. Unopened bags have a shelf life of six months when stored as recommended.

Packages

• 1 t Big Bag
• 50 kg paper bag