Join me, Kelton at Roadware at @ICRIorg’s Virtual Fall Convention #ICRIFall20. I’ve been selected to present in a product demonstration, Less Invasive Crack Repair for Concrete Floors and Structures on October 13, 2020. 2:40 – 3:10PM CST. See a preview of the presentation on YouTube. Learn more about the virtual convention here.
Roadware 10 Minute Concrete Mender™ and Easy-injection mixers make full depth crack repairs in hairline cracks without cutting. This less evasive crack repair technique breaks the rules for concrete repair.
Let’s look at these, “rules” one by one.
Broken Rule One: Hairline cracks are not worth the trouble fixing. Did you know that just about every crack in concrete started out as a hairline crack? Some so fine, you can not even see them with the naked eye. Cracking naturally occurs in concrete slabs as the concrete cures and shrinks. We use saw cut control joins to encourage the concrete to crack inside the saw cut or tooled joints. The problem is, the concrete doesn’t always listen and can crack where it wants to crack. We don’t like it, but that’s just the way it is. The truth is, we would fix hairline cracks if there was a good and efficient way to do it. Most of the time, we ignore hairline cracks and blame them on the nature of concrete and say things like, “It will be fine, you still have aggregate interlock and the crack is just on the surface.” Or, “All concrete cracks, and its just the nature of the product… Check out our new floor covering selection.” The customer, who just invested in a new concrete floor, is never happy with these explanations.
The truth is, we would fix hairline cracks if there was a good and efficient way to do it.
Broken Rule Two: You have to cut open crack if you really want to repair it. A repair material has to actually get into a crack so it will actually do some good. Anything short of that is no better than caulk. For the most part, this is true. We can’t repair what we can’t reach. Traditional cut and cover techniques us a diamond blade saw to open up a crack, forming a shallow well for Concrete Mender to accumulate and flow down into the crack. It works really well and Roadware has been doing this for over twenty years.
What is needed is a way to actively push repair products into hairline cracks. With a few simple techniques and Easy Injection Mixers, Roadware 10 Minute Concrete Mender can do the job. That brings us to:
Broken Rule Three: Crack injection requires pumps, ports, slow epoxy, and lots of time.
For a successful crack injection repair you need to accomplish three things:
- Delivery of materials to the repair area.
- The repair material needs to set before if flows away from the repair area .
- The repair has to be structurally effective.
Roadware Easy Injection mixers make getting Concrete Mender into cracks as small as 20 mil (0.02 inches) simple. Just drill a 3/8 inch hole into the crack and push the nearly water thin Concrete Mender into the cracks. You can actually watch the Concrete Mender flow along the length of the hairline crack. Leave the expensive injection pumps in the shop. A cartridge of Concrete Mender and a manual application gun is all you will need.
Roadware 10 Minute Concrete Mender starts to thicken and cure in about 5 minutes after application, so the material will stay where you put it. Traditional injection epoxies take hours to cure. In many cases, at the end of the day, the epoxy all ends up under the slab and no longer in the crack.
Roadware 10 Minute Concrete Mender™ with Microdoweling™ penetrates traditional bond lines and repairs concrete from the inside out. This structural polyurethane will not become brittle over time. Epoxy injection resins become very hard and brittle. As the concrete deflects under traffic, the brittle epoxy will start grinding away at the bond-line and the deterioration will start all over again. Roadware 10 Minute Concrete Mender is designed to restore aggregate interlock and deflect with the concrete under heavy traffic and loading. This structural polyurethane will not become brittle over time and is designed to bring the cracked concrete back to original pre-cracked condition.
For many years, engineers have looked for ways to fully inject repair polymers into cracked concrete structures. The general consensus is to seal off the crack with a sacrificial epoxy and install injection ports every few inches. Then thick epoxy is injected under high pressure into the crack with expensive resin injection pumps. The process is time-consuming, the epoxy is brittle, the equipment is expensive and the skill level is highly specialized. This makes epoxy injection slow, expensive and not really effective in the field.
At Roadware, we look for ways to make concrete repair fast, effective and easy.
Fast is better. When injecting Roadware 10 Minute Concrete Mender into concrete, the fast gel and cure time allows you to make a full depth repair from the bottom of the crack up to the top. If the crack you are injecting has a large hidden void, Concrete Mender repairs will start to gel and plug up the void in several minutes. Injection epoxy that takes several hours to cure will sink to the bottom of your crack and pool in the base before it has a chance to cure.
Effective. Concrete Mender is a Structural Polyurethane**. It is about as hard as typical concrete with much greater tensile and bonding strength. It is super thin at 8cps with a surface tension 1/3 of water. It can to penetrate concrete cracks and surfaces. Concrete Mender does not need to be forced into cracks with high pressure pumps and extraordinary methods. Concrete Mender can easily flow into cracks and fissures with just simple manual tools and a specially designed application mixer. You can repair more cracks in less time with less waste then ever before. Repairs are structural in nature and will move with the concrete, not against it like very hard epoxies.
Easy Application. For a repair to be effective in the field, it has to be simple enough for crews to apply efficiently. Installation productivity saves money.
- To start, simply drill a 3/8″ diameter hole about one inch deep into the crack at several points along the crack. Clean the crack and holes with a vacuum.* (Click here to learn how to work safely around silica dust).
- Tape off the top of the crack and around the holes you just drilled with clear duct tape or Gorilla Clear Repair Tape. These tapes have a good adhesive that will stick to the surrounding concrete. Do not use packing tape or other tapes without testing them first.
- Assemble a cartridge of Roadware 10 Minute Concrete Mender using out specially designed Soft-tip static mixer. Purge the cartridge of air as directed and insert nozzle into the first hole you drilled earlier.
- Gently squeeze the handle of the gun and slowly inject Concrete Mender into the crack. Work product into several holes at a time, moving the cartridge back and forth among them. Allow time for the Concrete Mender to start gelling in the bottom of the crack. As the crack starts to fill completely, you will see Concrete Mender flow under the clear tape from one drilled hole to the other. You may see air bubbling up from one hole as you inject Concrete Mender into adjacent holes.
- Once the crack is filled to refusal, move on to the next few drilled holes until the whole crack is filled.
- After 10 minutes at 70 degrees or 23 C, pull the tape. You can use a razor scraper, grinder or polishing device to remove and excess material and blend in the repair.
Using Roadware 10 Minute Concrete Mender and Soft-tip injection mixers, you can structurally repair concrete cracks and delaminations with simple tools and methods. This unique system saves time and money and allow for a high production rate for installers. The drill hole/inject method is much less invasive than traditional cut and fill methods and creates a lot less silica dust on the jobsite. The Microdoweling properties of Concrete Mender and Soft-tip Injection promises to be a winning combination for tough concrete repair challenges.
*“Workers may be exposed to dangerous levels of silica dust when cutting, drilling, grinding, or otherwise disturbing materials that contain silica. These materials and tasks are common on construction jobs. Breathing that dust can lead to serious, often fatal illnesses.” The Center for Construction Research and Training. Click here to learn how to work safely with silica.
** Structural Polyurethane: A polyurethane based material that restores structural integrity and aggregate interlock to distressed concrete by using low surface tension and low viscosity to penetrate concrete surfaces and cross-linking polymer chains to bond directly to the concrete-aggregate matrix. This bonding action utilizes capillary forces to self-inject polymer chains into the surrounding concrete. This material should have a modulus of elasticity less than the surrounding concrete and should not become brittle over time. This material may be combined with manufactured sand to form a PCC compatible polymer concrete that can structurally repair concrete cracks and spalls.
Start out by adding a small amount Concrete Mender to the prepared crack and noting where material in running beyond the slab. Add a light dusting of silica sand or fine quartz to the crack and some more Concrete Mender. The Concrete Mender will combined with the particles of sand to form a quick setting, “mud” at the bottom of the crack. Repeat as necessary and repair the full depth of the slab.
This will be a structural repair with no ports, no pumps, and almost no down time.
For the first time, Roadware 10 Minute Concrete Mender™, the industry’s only Microdoweling™ concrete repair polyurethane, is available in 50ml mini cartridges. The mini cartridge offers precise application control that is perfect for repairing hairline cracks. Each mini cartridge comes with a needle tip mixer and is simple to use. Use the 50 ml cartridge with the Roadware 5150 application tool. Each cartridge will repair about 10 feet of hairline cracks or 3 feet of 1/4 x 1/4 inch cracks.
|Roadware 80105 50ml 10 Minute Concrete Mender™ mini cartridge with mixer and needle tip.|
Use Roadware 10 Minute Concrete Mender to repair and re-bond delaminated concrete slabs.
Roadware delimanition repairs are featured in the July 2008 issue of Concrete International. This is the official publication of the American Concrete Institute. The article was written by Nelson Tonet, President of Express Polymers and a Roadware distributor.
“Delaminations in concrete floor slabs can be difficult to repair in a cost-effective and timely manner. A newly developed product (Roadware 10 Minute Concrete Mender™) that uses a two-part hybrid polyurethane with a viscosity similar to water can significantly reduce the difficulty of performing delamination repairs by easily flowing up to 10 ft (3 m) from an injection point and penetrating deep into concrete surfaces. The product also speeds up repair by setting in only 10 minutes, allowing the repair to be checked by sounding only 30 minutes after product placement.”
View full article in PDF format Delamination Repairs PDF
Here is a Roadware synopsis.
Roadware 10 Minute Concrete Mender™ is an excellent choice for repairing concrete slab delaminations. The very low viscosity of less then 8 cps and the exclusive Microdoweling™ penetration properties of the material allow it to flow deep into delaminated concrete voids. The Concrete Mender will restore aggregate interlock and will allow dynamic load transfer under heavy traffic. The expense and mess of pressure injection with epoxy can be avoided.
Two methods of repair have been successful. The first involved dry diamond drilling a 2 or 3 inch (5-8 cm) diameter hole into the concrete slab down to the delamination. Dust is removed with a shop vacuum. Roadware 10 Minute Concrete Mender is poured or pumped into the void. Only one or two inches (3-5 cm) of head pressure is required to push the material as far as 10 ft (3 m) into the delamination. When the material backs up to the top of the hole and the void is filled, silica sand is added and the hole is filled flush with the surface. Soundings are made with a hammer to verify the delamination is repaired in about 30 minutes after application.
Another method is to drill multiple 3/8 inch (1 cm) holes into the concrete down to the delamination. Remove dust with a shop vacuum and inject pre-mixed Roadware 10 Minute Concrete Mender™ with a syringe tipped with a rubber gasket. With this method, you can actually see the material exit the adjacent hole and verify the material is filling the delaminated area. After filling, the holes are blended into the surrounding concrete with silica sand and Concrete Mender or re-drill 1/4″ (5 mm) deep and fill with a color matching concrete mortar.
See the movie:
Both methods will yield good results and are more cost effective than epoxy injection.
The same Microdoweling™ properties of Roadware 10 Minute Concrete Mender™ that make the material excellent for repairing horizontal surfaces also make a good choice for vertical repairs.
In March, you donated the Roadware kit to bind the cracks at the Hope Alive! Clinic in Haiti. THANK YOU FOR YOUR GIVING AND KIND HEART.
We went to the Atlantic City airport with the msds. They refused to allow us to bring the tubes on the plane. (they really didn’t know how to read the msds sheets either)
Anyway, we shipped the package via Philadelphia-container-Haiti. It arrived in time for our July 8th trip.
We brought along a Pastor who is also a “concrete guy”. He stated that he had never worked with a product that was so easy and did such a great job. As you can see in the attached photos, the fissure is completely sealed. As I mentioned in our phone conversation, the epi-center of the quake was only 6-7 miles from our clinic. We even have 2 sets of tubes left over!! (the neighbors will benefit)
I do not know how to say thanks but to just say “thanks” . Your kindness has made a difference with Hope Alive Clinics and the Haitian people. visit www.hopealiveclinic.org for more pictures of the teams and clinic activities.
If you are ever in the Philadelphia area, please look us up.
Again, many thanks and God bless you and your great company.
Director, Hope Alive! Clinic Ministries”
UPDATE: See: Concrete Mender™ Full Depth Crack Injection
Roadware 10 Minute Concrete Mender™ is an excellent choice for repairing full depth concrete slab cracks. The very low viscosity of less than 8 cps and the exclusive Microdoweling™ penetration properties of the material allow it to flow deep into cracks. The procedure below illustrates Microdoweling™ in action. The Concrete Mender will restore aggregate interlock and will allow dynamic load transfer under heavy traffic. The expense and mess of pressure injection with epoxy can be avoided.Here is a parking deck project located in the North Eastern United States. Hairline cracks run 9-12 inches deep through the deck slab. The contractor drilled 1 1/2 inch holes, 2-3 inches deep into the hairline cracks approximately every 18 inches. Inspection from the floor below reveals full penetration without pumps or ports. Engineers tell us that Roadware Microdoweling™ is quicker and more cost effective than epoxy injection. The results speak for themselves.