Batimix Mortar 681

Description

BATIMIX Mortar 681 is a pre-packaged shotcrete mixture used in wet-process applications to enhance sulfate resistance. It contains Portland cement type V, chemical additives, and carefully-graded fine and coarse aggregates. It exhibits enhanced shotcrete characteristics and physical properties.

BATIMIX Mortar 681 is thoroughly mixed with water and introduced into the shotcrete equipment. The wet material, which exhibits improved cohesion characteristics, is pumped through the hose and compressed air added at the nozzle. It impacts the surface at high velocity resulting in a well-compacted product that is easy to place and consolidate.

Main Purpose

BATIMIX Mortar 681 is used to strengthen and repair existing structures. It is also used to build complex architectural shapes that meet the design specifications of skateboard parks, swimming pools, and earth retaining structures. The surfaces can have horizontal, vertical, or overhead orientations. This product is also suitable for the lining and rehabilitation of cementitious-based substrates, which include sewers, tunnels, reservoirs, and water mains.

Features

BATIMIX Mortar 681 has the following characteristics:

• Easy to use, suitable for both interior and exterior shotcrete works
• High early and final compressive strength without added chlorides
• Eliminates cracking and surface fissures
• Reduced bleeding and sagging
• High degree of adhesion and bonding to the projected substrate
• Improved resistance to sulfate attacks

Properties

• Appearance : powder
• Bulk density : around 1.43
• Chloride content : nil
• Grain size : 0 to 4 mm
• Water per 25-kg bag: 3.5 – 4.5 liters
• Initial flow consistency (ASTM C 230): 110 mm
• Average Vicat setting time (ASTM C 191): 15 – 30 minutes
• Compressive strength after 28 days (ASTM C 109): min. 40 MPa
• Pull-off strength against concrete at 28 days (EN 1015-12): min. 0.85 MPa

Health and Safety

BATIMIX Mortar 681 contains cement that is irritating to the eyes and skin. In case of contact, rinse immediately with plenty of water. Wear suitable gloves. For further information, kindly refer to Material Safety Data Sheet.

Directions for Use

1 – Substrate preparation 1.1 – Support and nailing works: All surfaces to be in contact with BATIMIX Mortar 681 must be free from dust, oil, grease, or any other foreign substance that may interfere with the bond of the material. Remove all loose or delaminated sand and rock. Moisturize the area with clean water, leaving the substrate saturated but free of standing water (SSD condition).

1.2 – Repair and rehabilitation works: Concrete must be structurally sound and fully cured. Saw cut the edges of the repair location to a depth of at least 15 mm. Remove all spalled, severely cracked, deteriorated, and loose concrete from existing substrate by chipping, water blasting, or other mechanical methods. Care should be taken to remove all oxidation and scale from the exposed reinforcing steel. Adequate pre-wetting with no glistering water should be achieved prior to shotcreting.

2 – Product preparation A 25-kg bag of BATIMIX Mortar 681 should be mixed with 3.5 to 4.5 liters of clean water, depending on the desired slump consistency. The mixing should be done with a medium-speed mechanical mixer for a minimum of 3 minutes until obtaining a consistent homogenous material.

3 – Application Place the wet BATIMIX Mortar 681 into the hopper of the delivery machine, such as a concrete pump, and shot directly onto the substrate. The nozzle operator should give enough attention to the angle of application, i.e. 90° and distance from the substrate, normally 0.8 to 1.8 m. Refer to ACI 506 “Guide to Shotcrete”.

The surface can be trowelled smooth while BATIMIX Mortar 681 is still wet. Typical application depths can be up to 150 mm. In case greater thicknesses are required, it is recommended that subsequent layers be applied after 24 hours from the first application.

4 – Curing Good curing conditions are extremely important to optimize the physical properties of BATIMIX Mortar 681. Curing should start soon after the material has reached its initial set according to ACI 308 “Practice for Curing Concrete”. Continuously moist cure for a minimum of 7 days. Alternatively, moist cure for a minimum of 24 hours and then apply a curing compound which complies with ASTM C 309. This is particularly critical in high ambient temperatures, high winds, and low humidity.

Specifications / Compliance with Standards

BATIMIX Mortar 681 meets the requirements of ASTM C 1480 for Packaged, Pre-Blended, Dry, Combined Materials for Use in Wet or Dry Shotcrete Application Type FA, Grade SR (sulfate resistant).

Storage

BATIMIX Mortar 681 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

• 25 kg paper bag