
Fiber reinforced shotcrete mortar for wet process applications - Reduced shrinkage
BATIMIX Mortar 683 is a pre-blended shotcrete mixture designed for use in wet process applications where reduced shrinkage is sought. It contains Type I Portland cement, selected additives, fibers, and carefully-graded fine and coarse aggregates. It exhibits enhanced shotcrete characteristics and physical properties.
BATIMIX Mortar 683 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.
BATIMIX Mortar 683 is used to strengthen and repair existing structures and build complex architecture shapes for skateboard parks, swimming pools, and earth retaining structures. The surfaces can have horizontal, vertical, or overhead orientations. This product is suitable for the lining and rehabilitation of cementitious-based substrates of sewers, tunnels, reservoirs, and water mains structures.
BATIMIX Mortar 683 has the following characteristics:
BATIMIX Mortar 683 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.
1 – Substrate preparation 1.1 – Support and nailing works: All surfaces to be in contact with BATIMIX Mortar 683 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 683 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 683 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 683 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 683. 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.
BATIMIX Mortar 683 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 FR, (fiber reinforcement) Class I.
BATIMIX Mortar 683 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.