Single-component, fibre-reinforced mortar for concrete repairs.

Application of SpECbuild MC500 Fibre is crucial for achieving optimal performance and durability in concrete repairs. Proper preparation and methods will enhance the longevity of the repair work. Below are the essential steps for successful application:

Preparing the Substrate:
– Remove all degraded and/or loose concrete until a sound and solid substrate is achieved.
– Where necessary, clean the concrete and reinforcing steel by sweep blasting or other approved mechanical methods to remove all dirt, corrosion products, cement laitance, grease, oil, previous coatings, and other deleterious elements.
– Any previous repairs that are no longer thoroughly bonded must also be removed.
– Pre-soak the substrate with clean, potable grade water to obtain a saturated surface dry (SSD) condition. Preparing the Mortar:
– Pour into the mixer or a rust-free mixing vessel the pre-gauged amount of potable grade water needed to obtain the required consistency.
– For Trowel application, use 2.75 – 3.25 litres of water per 25 kg bag.
– For Spray application, use 3.25 – 3.75 litres of water per 25 kg bag.
– Start the mixer and slowly add the complete bag of SpECbuild MC500 Fibre to the water in a continuous flow. Mix for 1 to 2 minutes, checking for a well-blended mix. Scrape any unmixed powder from the bottom and sides of the mixer and mix again for a further 2 to 3 minutes.
– Depending on the amount of mixed material required, a mortar mixer or a slow speed heavy-duty drill with an appropriate mixing paddle may also be used. Avoid mixing manually as this may adversely affect several of the mortar’s characteristics. Application Methods:
– SpECbuild MC500 Fibre may be applied by trowel to vertical surfaces in layers up to 60 mm thick or for overhead applications in layers up to 30 mm thick without the use of formwork.
– In cases where higher buildup of SpECbuild MC500 Fibre is required, leave the surface of the previous layer in a rough condition, allow to harden, then wet the surface with water prior to applying the second layer.
– It can also be spray applied using a suitable piston or worm-screw type rendering machine, such as a Turbosol or Putzmeister. Do not use a continuous mixing type rendering machine. Curing:
– In accordance with good concrete practice, all exposed surfaces of SpECbuild MC500 Fibre must be immediately cured after application, using wet hessian covered with polythene sheeting. Failure to cure the open surfaces can cause the formation of cracks due to plastic shrinkage, especially in hot and/or windy climatic conditions. Reinforcement Steel Preparation:
– For repairing concrete elements damaged due to reinforcement corrosion, it is recommended to use mechanical means of abrasion to remove corrosion deposits from the exposed reinforcement prior to coating with SpECcoat Zn25.