Category Archives: earthquake damage

Repairing Cracks in Driveways and Patios Updated

One of the most common calls we get is asking how to repair a crack in a driveway or patio.  We designed Roadware MatchCrete™ Clear with this in mind.  Roadware MatchCrete™ Clear is a UV stable clear polyurethane hybrid that makes effective repairs to most exterior concrete surfaces.  By simply leaving the repair clear, the color of the surrounding concrete shows throughout the repair.

The first step to a good looking crack repair is to rout-out or cut the repair open with a diamond blade grinder.  You only have to go about 1/4″ x 1/4″. This will create a recess for the material to rest as it soaks down further into the crack.  Skipping this step will allow the material to flow uncontrollably on the surface and will create a messy looking repair.

 

Apply cartridge mixed MatchCrete™ Clear directly to the crack. Small amounts of silica or quartz sand can be added to keep the material from flowing out the bottom of the slab.  If necessary, matching colored sand can be used to match colored concrete areas. Fill the crack to slightly below grade to prevent material from flowing on to the surface of the concrete.

After a year of service, the repair above still looks good.  Please note, MatchCrete™ Clear is not a soft expansion joint material and should not be used in joints that are designed to move.  Always give careful consideration as to why the concrete cracked in the first place and what the concrete is expected to do in the future before making repairs of this nature.

UPDATE:
September, 2013
We have a new video for driveway hairline crack repair:

Roadware 10 Minute Concrete Mender™ Best Practices

 

ROADWARE 10 MINUTE CONCRETE MENDER™

Buildings marked for demolition in Christchurch, New Zealand.
Recently, our Roadware distributor in New Zealand requested a list of best practices for using Roadware 10 Minute Concrete Mender™.  Contractors in Christchurch are using Concrete Mender to repair many meters of cracks following recent earthquakes.   
Best
Practices
Storage
and Transportation
1.
Keep cartridges in original foil bag and store in
an upright position.
2.
Store on a cool dry place between 10-28 degrees
C (50 – 80 F). If cartridges are allowed to freeze below – 10 C (14 F) some material separation
can occur.  Return material to 25 C (75 F)
and shake or mix to re-blend before use.
3.
Handle with care. Punctures to the bag can cause
moisture contamination. Rough handling can cause cartridge cracking and
leakage.
4.
Ship in upright orientation in original shipping
containers.
Usage
1.
Read and follow illustrated instructions.
2.
Use gloves and safety glasses.  Concrete Mender is very thin and can
splash back if applied erratically.
3.
Make sure the flow-restrictor and mixer seat
properly.
4.
Use a new flow-restrictor and mixer every time.
5.
Small cracks less than 2mm should be cut open to
5mm for best results.  The 5mm cut
will form a, “well” for the product to accumulate as it soaks down into the
crack and will reduce material spreading on the surface away from the repair
area.
6.
Once material is flowing from the mixer, keep the
tip pointed down.  Use the thumb
release on the gun to stop the flow.
7.
Discharge the material from the cartridge
firmly.  Working too slowly can
cause poor mixing.
8.
Always apply a coating of Concrete Mender into the crack or spall before adding sand. This will give you better penetration and bonding.
9.
When applying with sand, make sure the sand and
repair area are completely saturated with Concrete Mender.
10.  Use a shop vacuum or compressed air to remove as much dust and contaminates from the
repair area.
11.  If you suspect there is water on the bottom of the crack that you cannot remove, repair the bottom half first and allow it to cure (turn grey) before repairing the top half.
12.  When working at below 0 degrees C, use a propane torch or similar method to remove any surface frost from the concrete before applying the material. Keep Concrete Mender and sand at room temperature before use.

13.  Needle tip mixers are great for better control and pinpoint application. They also can easily clog up when left filled with mixed product. Do not try and force a mixer or tip to clear by adding more force to the gun. You can blow out the rear seals and cause a mess.  Get a new mixer or tip and start over.

Concrete Mender™ is injected into cracked walls in Christchurch, New Zealand.