How to Mix Mortar and Fiber

Mortar keeps a strong bond between bricks in a building.

Mixing in fiber is a good way to reinforce mortar, improving impact resistance and reducing shrinkage cracking. Fiber reinforcement began in the 1940s as a way of dealing with the problem of mortar cracking when stressed. The additive comes in packets, which you will need to mix with the mortar in a specific manner to get the desired results.

Things You'll Need

• 1 55-lb. bag of mortar mix
• 1-4 packets of fiber
• Large bucket or tub
• Shovel
• Trowel
• Small cement mixer
• 1 gallon water

Instructions

1. Depending on how much reinforcement is desired, use one to four packets of fiber per 50- to 60-pound bag of mortar.

2. Shovel the mortar into the tub, add the water and mix with a trowel for smaller projects. For larger projects, use a small cement mixer to mix the mortar and water.

3. Add the fiber during initial mixing of the mortar, according to the mixing instructions on the mortar packaging. Add the fiber gradually over a period of about two minutes. If you're working with large amounts, add a minute for each 22 pounds you are mixing.

4. Don't exceed four packets of fiber per bag of mortar and do not add more water than the mortar packaging recommends.

References

• RetailSource: Fiber Reinforced Concrete
• CTS Cement: Concrete Pharmacy Fiber
• Kuraray: Mix Instructions for PVA Fibers