“THE CONCRETE STAPLE”
THE BEST CRACK REPAIR
PRODUCT ON THE MARKET
SANTA ROSA, CA
“THE CONCRETE STAPLE”
Restores the necessary multi-directional strength of concrete.
“The Concrete Staple” is a unique, custom made, engineered, U shaped concrete crack repair product that is made with a patented process. The properties of our custom, engineered steel Staples, have been specifically FORMULATED to restore the normal multi-directional strength of concrete. This restored multi-directional strength is absolutely necessary to stand up to the tons of powerful, continual, expansion and contraction, vertical and horizontal shearing, and torque-ing of both the concrete and the ground around it.
FREQUENTLY ASKED QUESTIONS & GENERAL INFORMATION
For the tensile strength of concrete we are using 250 lbs per sq inch. Because there are so many variables in concrete, there are a number of theories regarding it’s tensile strength. Some experts feel it is between 7% and 15% of the compressive strength, others subscribe to an average of 10% of the compressive strength. Now, some experts feel as though the maximum tensile strength of normal concrete is no higher than 225 to 250 PSI. This idea is based on the theory that once you pass the optimum of 225 to 250 PSI the added cement content will actually reduce the tensile strength as raw cement itself has a fairly low tensile strength. We are using the higher of the two figures of this latest theory for our calculations. 250 PSI
Concrete Product Resource (CPR) warrants the special engineered steel it’s staples are made from have a Yield strength of 114,000 PSI and a Tensile Strength of 130,000 PSI. and warrants them to be free from manufacturing defects for 10 years. CPR will replace defective material only. There are no other warranties by CPR of any nature whatsoever, expressed or implied including any warranty of accountability or fitness for a particular purpose in connection with this product. CPR shall not be liable for damages of any sort including remote or consequential damages resulting from any claims, breach of warranty whether expressed or implied whatsoever. CPR shall not be liable under any legal theory for special or consequential damages.
Once poured, most of us view concrete, as a simple, unmoving mass that just lays there as a walkway, patio, driveway, foundation, retaining wall or even a swimming pool shell etc.
Nothing could be further from the truth. Concrete is a complex material that is under, continuous, almost unbelievable amounts of multi-directional stress and movement. This is due to expansion and contraction of the concrete itself and the ground around it. These tons of expansion and contraction are caused by normal hot/cold and wet dry cycles. (See drawings below)
TONS OF EXPANSION & CONTRACTION
TONS OF TOURQUE-ING
TONS OF HORIZONTAL / VERTICAL SHEAR
Under normal circumstances, concrete is designed to withstand those tons of stress and movement. Concrete has a built in multi-directional strength and it takes an unusual event to break concrete.
However, once broken these tons of stress and movement makes it almost impossible to repair the break. The repair product has to restore the multi-directional strength of the concrete at the break point. “The Concrete Staple” by Concrete Product Resource is designed to restore that multi-directional strength. Nothing else on the market does this.
After gluing, or injecting, a concrete crack with epoxy, the epoxy fails to restore the multi-directional strength at the break point, not because of the epoxy, but rather due to a misunderstanding about concrete. Concrete doesn’t break, it fractures. At
the stress point, the dried cement paste, which is the only thing holding concrete together, develops thousands of tiny cracks until the two pieces finally separate. These thousands of tiny cracks in the cement paste affect both faces of the broken concrete anywhere from 1/4” to as much as several inches. Therefore, from an Engineering standpoint, you simply cannot glue broken concrete back together. Under normal stress, it has to eventually fail. (See drawings below)
DRIED CEMENT PASTE HOLDS
CONCRETE TOGETHER TO
THOUSANDS OF TINY CRACKS
IN CEMENT PASTE CANNOT BE
GLUED BACK TOGETHER
Again, the failures we are now seeing with carbon fiber staples can be attributed to a misunderstanding of concrete.
Concrete is constantly moving in multiple directions, literally with tons of power. Carbon fiber is only strong in one direction: Tensile. (trying to pull it apart) In all other directions it has to rely on being glued to the concrete. While both the carbon fiber and the epoxy used to glue it down with are very strong, the concrete itself is the problem.
The tensile strength of average concrete is approx. 250 lb per sq inch. The gluing surface of the average carbon fiber staple, on each side of the crack, is approx. 1.875 sq. inches.
This means the carbon fiber staple will break loose from the concrete, as it expands & contracts, shears and torques, with less than 475 lbs of energy movement. From an Engineering standpoint, it has to eventually fail under normal stress!
(See drawings below)
The epoxy/concrete bond fails at
Less than 475 lbs of lift movement
The epoxy/concrete bond fails at
Less than 475 lbs of shear movement
Many people misunderstand the function of rebar in non-engineered applications. While rebar provides shear strength, rebar is designed to “Stretch” at the control joints as the concrete expands and contracts. This is called “YIELD.” Therefore, because rebar is designed to yield, or stretch, at the control joints it obviously cannot be used for crack repair. Rebar stretches under the normal stress and the crack opens back up. (See drawing below)
BY CONTROL JOINT
TONS OF CONTINUOUS
EXPANSION AND CONTRACTION
REBAR STRETCHES AT CONTROLJOINTS SO CONCRETE CAN EXPAND AND CONTRACT, WHILE STILL PROVIDING SHEAR STRENGTH. REBAR CANNOT REPAIR CRACKS!
In most applications we recommend using a Setting cement like “Cement All” Made by Rapid Set. (Or equivalent) Can get at Home Depot etc. Inexpensive, water based, fast drying.
Or, if you like epoxy better use epoxy. On swimming pools we suggest epoxy. The key is that the product used to install our staple has to be non-shrink and be stronger than the concrete you are attempting to repair. “Cement All” has a rating of 9,000 PSI.
It depends on several factors, including the thickness of the concrete. On 4” thick concrete usually at 16” O. C. , patio’s, walkways etc. However, on driveways we suggest 12” to 14” and if you install at 12” O. C. it’s a good idea to use the next larger size on every third one so the holes don’t line up and create a weak line. On swimming pools 12” O.C. On 5” thick concrete no more than 13” apart and 6” thick concrete 11” apart. When installing the staples this close together you definitely want to use a larger size every other staple.
For thicker or unusual situations give us a call. 707-987-4534 9-5 PCT.
There are two parts to the “secret” of successful concrete crack repair, especially when it comes to flat work like patios and driveways etc. One, is having a product that will RESTORE the multi-directional strength of concrete ( “The Concrete Staple”) and the other is to understand the need for control joints and WHERE to install them.
“The Concrete Staple” will keep repaired cracks from coming back because they are engineered to restore the multi-directional strength of concrete.
However, on flatwork, most cracks are caused by expansion and contraction where there are too few control joints, so when you fix one area the concrete has a tendency to crack somewhere else. Concrete continues to expand and contract, torque and shear indefinitely. Installing control joints at the proper places usually solves the problem of additional new cracks.
(See FAQ # 9)
Yes. “The Concrete Staple” is being used for: DRIVEWAYS • PATIO’S • WALKWAYS, GARAGE SLABS • SWIMMING POOL DECKS • FOUNDATION REPAIR • SWMIING POOL REPAIR • RETAINING WALLS ETC.
Because all concrete cracks the same, (the dried cement paste fractures at the breakpoint) the same Concrete Staple engineering makes them the best cracked concrete repair system on the market. Again, they are the only product that restores the multi-directional strength of broken or cracked concrete
Concrete expands and contracts in squares, and it does so with amazing power. For example, in order for the average 4” thick concrete to contract with enough power to cause a crack it has to generate over 1,000 lbs per running inch. Therefore a 48” wide sidewalk has to generate an amazing 48,000 lbs of contraction in order to cause the four ft sidewalk to crack, and it continues to expand and contract indefinitely with that same amazing amount of power.
The “secret” then, is to know the necessary size of the squares we need to install. On flatwork ( sidewalks etc) on anything less than 8 ft wide, simply install a new control joint equal to the width of the walkway: Example: on a 4 ft wide sidewalk install a control joint every 4 feet ( 5 ft wide every 5 ft) etc. This creates the squares for equal expansion and contraction that concrete must have. If you don’t put the control joints where they should go the concrete will many times create a crack where the joint should be. (Cont’ below)
However, the maximum size square for 4” thick concrete is 8’. And if you look you will see that on average if someone did not put in a control joint every 8’ on a 4” thick slab, the concrete will usually crack right about at 8’ squares. We see a lot of this in 16’ ft wide driveways. So the problem is how do you staple the existing cracks at the 8’ sq location and then cut the new control joints? The answer is to staple the cracks and then cut smaller squares that do not line up with the old cracks. That way you don’t conflict with the newly stapled area. Squares smaller than eight ft are acceptable just don’t make them larger than 8’.
4 ft wide sidewalk with control joints every 4 ft,
with each section expanding and contracting in
separate squares, to and from the center of each
16 ft wide driveway
cracked at 8”
Staple old cracks and
install new control
joints approx. 5’ 4”
apart side to side and
as close to 5’ front to
back after stapling.
In FAQ # 2 you will note that the face of broken/ cracked concrete is full of thousands of tiny cracks making it impossible to glue it back together. The question is, how far back from the crack or break do these tiny cracks go? The answer is “you can’t be sure”. However, time and experience has taught us that a minimum of 6” away from the crack or break is, in most cases, a safe distance. The concrete 6” away from the crack is solid enough to hold the full power of the expansion and contraction of the concrete. Therefore, the shortest staple we sell is a minimum of 12” long. If there is a need of a pipe or ditch to run through the concrete we have both 18” staples and 24” staples. Use the one that will give you a minimum of 6”away from the beak for the anchor hole. If the ditch is wider than our staples to work simply install A staple on each side of the ditch.