Our building sturcture has some precastprestressed hollowcore floor slabs. What are the side effects of paving asphalt over concrete. Overlays may include polymers, portland cement concrete, or epoxies. This mix is ideal for repairing and topping damaged concrete surfaces that are less than 2 in. Polymerbased cement resurfacers are formulated to transform cracked, spalled, weatherworn concrete to likenew condition. Oct 14, 2018 a micro topping is a cementitious product that is normally used as a solution to repair old cracked concrete. The key to a successful bonded topping is proper surface preparation. Skeptics fail to recognize that pouring over the top of sound concrete is no different than pouring over a supercompacted stone base. Cracking can be the result of one or a combination of factors, such as drying shrinkage, thermal contraction, restraint. This stamped concrete overlay was installed over an old, worn concrete patio that sloped towards the house. If the existing concrete is in good shape structurally, you can pour new concrete over it to freshen it up. Jun 24, 2014 concrete is not usually a compacted surface because it hardens no matter what it is poured over.
When user cost with initial cost is considered however, white topping is cheaper than. Causes for weak concrete include drying out the surface too quickly or low quality concrete. Surecretes micro topping is a single component thin concrete overlay that is a selfbonding cement based, for interior. A concrete overlay makeover how i resurface ugly concrete. If the roller is overloaded with sealer, it tends to drag large amounts across the surface in streaks and ribbons. I plan on doing a project similar to the one in the video for my garage, and was curious if the driveway in the video has cracked or pitted. Concrete broom overlay resurface old concrete mix 6000psi. I am more concerned about the cracks and uneven areas in the existing walkways. Cracking unexpected cracking of concrete is a frequent cause of complaints. As the topping concrete is placed, use stiffbristle brushes to scrub the paste portion of the topping concrete into the ssd substrate ahead of screeding the topping surface. The condition of the existing slab is the primary factor that determines how long the new concrete will last.
Conventional whitetopping conventional concrete overlay placed directly over an existing asphalt pavement has a long history of use, and the practice is well established. A microtopping is a cementlike product that is normally used as a solution to repair old cracked concrete. Dec 15, 2001 yes, you may pour a concrete pad overlay over an existing slab. Whitetopping is a rehabilitation alternative for flexible pavements, which overlays an existing flexible hot mix asphalt hma pavement with portland cement concrete pcc surface. Avoid using air contents over 3% for interior slabs. Pouring concrete over old concrete instead of directly over a new gravel foundation limits your ability to maximize the slabs lifespan. How to resurface cracked concrete with brickform overlay. Microtek one coat micro topping is a thin concrete overlay mix that can be applied on floors and walls. I am going to pour 2 of concrete over a 4 cracked slab of concrete behind my back door. Put on safety glasses and use a hammer and chisel to chip out oil stains or tree sap. It doesnt have near the strength of concrete when you measure them inch for inch. Apr 25, 2016 the new concrete certainly isnt going to float up in the air or slide off.
However, of recent origin are whitetopping techniques that depend on a bond between the concrete resurfacing and the existing asphalt pavement sur. Jul 17, 2017 if the chips in your driveway formed over time, skim coating and sealing the surface is a simple cosmetic solution. Is it possible to post an update to the how to repair cracks and resurface a concrete driveway video to show how it held up after a few monthsyears. Crackchasing also creates clean, bondable surfaces. From a simple resurfacing to something quite decorative, the possibilities are amazing. A concrete overlay can give your ugly concrete patio, floor, or pool deck a makeover. Ultrathin white topping is a rehabilitation technique in which a 50 to 100 mm thick layer of high strength, fiberreinforced, cement concrete is place on a milled surface of rutted andor cracked bituminous concrete pavement. White topping over asphalt lowers the heat island effect and cuts maintenance costs with no seal coating andor resurfacing needed. There are a variety of sakrete concrete repair products available to fix concrete that has begun to deteriorate. A partially bonded topping is a failureif portions of the toppings did not bond, it will most likely crack and spall. The overlay material was a total of 14 inch thick over an old concrete floor. Reduce evaporation over the slab by using a fog spray or slab cover. Oct 17, 2012 how to take an old driveway and resurface it using brickform sm professional grade micro topping. Skim coating weak concrete is only a temporary fix.
The thin mix is laid over the old concrete, slipping into cracks and crevices, hardening quickly into a smooth surface. Pouring concrete over concrete everything about concrete. The process involves applying a layer of cement over the concrete. One of the best tools that can be clean all the debris out of crack is a stiffbristle broom.
Pouring concrete over an existing concrete slab how to bond them together they always say rome was not built in one day, and this was the place that changed the looks of architectural structures that we see today. Surebroom is a concrete broom overlay mix that comes in a gray or white mix. Thanks to innovative ardex fasttrack products, long drying and waiting times are a thing of. Spalling, the pits that form in concrete, happen when too much water is used in a concrete mix, weakening it. This includes removing sand, dead leaves, and gravel.
Apr 23, 2020 perhaps the most common cause of cracked concrete is standing water cracks in concrete can also be caused by unevenly dense subsurfaces below the slab. Skim coating can freshen up old concrete blocks and give your home or a wall on your property a new look. Steps involved in pouring concrete over existing concrete slab step 1. Before pouring concrete over existing concrete driveway or sidewalk surfaces, remove stains and loose material so the new concrete can stick properly. Ensure the slab is structurally sound to make the best decision on whether you should start over or repair the concrete you need to ask a few questions. Experts who work each day in the blacktop industry, refer to blacktop as flexible pavement. Put these overlays on cracked concrete, and you will get a cracked overlay. Lifecycle cost lcc analysis of white topping and ac overlays asphalt concrete were conducted by lowey 2005. You need to consider the added height and weight of the overlay on the existing structure. How to repair cracks and resurface a concrete driveway.
Applied to concrete surfaces, it strengthens and reinforces the concrete to render surfaces suitable for hightraffic areas. To prevent cracking in the overlay, make sure that the finish. Precast topping concrete engineering general discussion. After repairing the concrete cracks with epoxy, apply a layer of cement stucco to the driveway. Concrete resurfacing of asphalt pavements bonded concrete resurfacing of composite pavements bonded overlay systems unbonded concrete resurfacing of concrete pavements unbonded concrete resurfacing of asphalt pavements thinner concrete pavement or short slabs unbonded systems acpa bcoa or bcoa me h3 to 6 in. We transformed an old cracked concrete slab by resurfacing it. When the concrete does begin to show signs of age, you have two choices.
Back then there wasnt much for user friendly products that would. If your plan is to install a decorative concrete floor, skraffino concrete micro topping is the easytoinstall and cost effective solution youve been looking. In the past, when a concrete patio or driveway started to show serious signs of aging, using a jackhammer or bringing in a bulldozer were the only repair options. Whether youre filing in a crack, repairing a section of concrete, or pouring a whole new layer over an existing layer of concrete, getting the new concrete to adhere to the old layer can be difficult if. Resurfacing is pouring a thin layer of sandmix concrete over the existing concrete. How to use thinset morter to resurface concrete home guides.
Concrete that is damaged on the surface but is structurally sound can be repaired by resurfacing. Breaking up the old concrete to pour new requires more work, but can you pour concrete over existing walkway or patio surfaces successfully. The disadvantages of pouring concrete over existing. Sweeping dirts debris over the existing concrete slab will allow bonding to take place. Usually, these consist of a blend of portland cement, fine sands, polymer modifying compounds, and other additives that make the surfacer easy to apply and spread over existing concrete surfaces. We transformed an old cracked concrete slab by resurfacing it to look like a new random stone. Oil, dirt and other debris can affect how the new concrete bonds with the old.
New slab on top of old concrete construction magazine. One proven solution is a thin concrete overlay called whitetopping. Being a concrete contractor since the early 80s, ive seen a lot of concrete that needs a new surface. Sandtopping mix features a uniformly blended mixture of portland cement, graded sand and other approved ingredients. If the cracks are there from the initial curing or settling of the floor, our teams normally crackchase or cut the cracks to remove the loose materials. One positive aspect of installing blacktop over concrete is the concrete provides a firm base for the flexible asphalt paving. We resurfaced the concrete with our overlay, stamped a cobblestone pattern into it, and pitched the overlay away from the house to shed water. How to take an old driveway and resurface it using brickform sm professional grade micro topping. Concrete resurfacer is a cementbased coating that forms a smooth, new surface right over the old concrete. It works best on inside applications and horizontal surfaces generating a smooth neat surface that otherwise will be almost impossible. Proper prep work is key to success when layering new concrete over old. A wellpoured concrete slab with a deep, sturdy foundation can last for 30 to 40 years. Photos below are courtesy of the black and decker home improvement librarys home masonry repairs and projects by creative publishing international.
Overlays are only as good as the subbase they are applied to. They are not intended to fix poor concrete, but instead are meant to give a new aesthetic look to concrete thats in good shape. Aug 28, 2017 if your patio, driveway, or other concrete slab is falling apart and losing its appeal then you need to give it a facelift. You can rip it out and replace it or go with the usually more economical alternative which is to repair it. On top of the hollowcore slabs, a 2 in topping slab is placed to finish it off. The solution to all of these problems involves a jackhammer and bags of one of the sakrete concretes. If you decide to use a portland cement, latexmodified, or epoxymodified concrete overlay, carefully follow the. How to skim coat concrete blocks home guides sf gate. Even new concrete has imperfections, whether it is cracked, blemished or discolored. Research paper white topping as a rehabilitation method. In this case, the long, thin streaks of white indicate overapplication of the sealer with a roller. Available in a white or gray mix, our thin overlay can be colored with any of our 30 standard overlay colors. Placing new concrete over old in decorative concrete. The major manufacturers of concrete products, including quickrete and sakrete, all sell concrete resurfacing products.
How to skim coat a concrete patio pour concrete surface. Patio or driveway concrete overlay is for old or damaged concrete with surecretes just add water mix and when applied properly, our broom overlay product test well over 6000 psi when cured. Whether its a question of cosmetic concrete repairs for a more attractive finish or installing hardwearing surfaces in commercial and industrial applications, ardex offers the right products no matter how diverse and challenging the requirements. For a new driveway, excessive chipping can indicate that the slab itself is weak. One such innovative pavement strengthening strategy is to provide thin or ultrathin white topping overlay.
Micro topping can be used over interior surfaces such as. If you have a cracked concrete driveway, you can repair the cracks and transform the look of your driveway. The mix design of the topping is the same as the interior slabs on grade 34 aggregate w min. Resurface a cracked concrete driveway do it right not over. As long as your walkway isnt cracked all the way through, you can coat the slab with a concrete resurfacer, a noshrink blend of portland cement, sand, and polymer additives that fills divots and makes a uniform finish. We dont rely upon the actual layers of the epoxy or polyaspartic coatings to fill in the cracks in a garage or basement floor. Yes, you may pour a concrete pad overlay over an existing slab. Since this discussion is on the best way to bond concrete, we will assume that your slab is good.
Repairing the concrete is one option, though the repairs themselves leave noticeable imperfections. Concrete pavement is occasionally poured over the top of unstable soils because concrete has the ability to bridge the instability. Thin concrete overlay micro topping mix tight troweled by. Cracking can occur in the overlay due to drying or plastic shrinkage. Asphalt, on the other hand, has to be compacted to get longevity and strength. Repair existing cracks and use a bond breaker over them to try to prevent a repeat of the same crack in the overlay. From the analysis, it was found that initial cost of white topping is much higher than an ac overlay. Pouring a skim coat over the surface is exactly what your concrete needs. Preparing for a topping concrete construction magazine. If i put wire mesh down first will the concrete i pour crack with such a deep base already present. These thicker streaks of sealer skin over on the top surface, preventing the sealer from fully curing. White topping also dramatically increases visual appeal over a cracked and damaged surface and offers a monolithic curb. Before topping installation, the plastic sheeting is removed and any standing water is vacuumed to leave the prepared surface in a saturatedsurfacedry condition. How to use thinset morter to resurface concrete home.
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