COMMON ANSWERS TO COMMON QUESTIONS
Here you will find answers to common questions presented to us. We do our best to explain our services better to give our customers a better understanding of what a job entails. Knowledge about a service provided gives a better understanding of the job at task and a level of assurance towards a quality finished product. Write to us if you don't see what you are looking for here. We will get back to you as soon as possible.
Asphalt paving will beautify the property you take care of, reduce liability risks, and increase asset values.
One of the primary concerns of asphalt paving is the value of the paving vs the costs. Cost can sometimes be fairly high in asphalt paving but this does reflect a value. An asphalt overlay (asphalt layed on top of existing asphalt) can often look like a new job, but if it is not done correctly, the lifespan of the overlay will be greatly reduced.
OVERLAYS
Preparation is everything with asphalt paving. Really, asphalt concrete pavement is not very strong. It is the base condition to what the asphalt is placed on that makes a difference. The base must be structurally solid;, if not, cracking in the old asphalt will come right through. This reflective cracking can occur fairly quick and can show within one year or if the cracking is caused by roots, they may return within weeks. Paving over the cracks is usually not recommended unless some sort of remedial work is completed prior to work or some other method of reducing the reflective cracking is made.
RECONSTRUCTION
In some cases, overlays are not recommended. Places with alligator cracking (an area of numerous closely spaced cracks) indicates a base (gravel) failure. This is a problem below the asphalt to which an overlay will not solve. A soft base will cause excessive deflection on wheel loading causing the pavement to exceed its flexible limits and crack. Commonly this requires cut out and removal of the existing asphalt, the base reconstructed, and reinstated with new asphalt. Sometimes, these cut outs can be completed in small areas, but if there are numerous areas of faulty base, a total reconstruction is often a more effective and sometimes cheaper way to go.
Total reconstruction can often be quite pricy because of the large work involved around removal of the existing material. However, reconstruction should solve any problems previously noticed with the old asphalt.
HOW DEEP SHOULD THE ASPHALT BE?
Generally with new asphalt concrete pavement, the minimum depth is dependant on the loading type. Generally 3 inches is ample for most applications. Sometimes you may go as low as 2" but this would be for light loading areas such as pedestrian walkways. More criticle however is the base condition. If the base is not sound, the pavement won't last.
Should the area be subjected to large amounts of loading such as a garbage truck or fire trucks, then it may be suitable to place 4 or more inches of asphalt concrete pavement in two lifts (layers).
WHEN SHOULD I PLAN FOR PAVING?
On the west coast, it is best to plan the paving during dry periods. If you have larger jobs, it is best to leave them for the dry months where the project may take two or more days. This way, there is a better guarantee that the working conditions are optimal. On smaller jobs such as driveways, the time frame for paving can be fit into any dry day, however, there are certain restriction such as paving during a frost period is not a good idea.
Overlays on the other hand must be restricted to not only a dry day, but on a day when the surface is dry and relatively warm.
HOW LONG DO I HAVE TO WAIT BEFORE DRIVING
ON NEW ASPHALT?You can drive on asphalt once it has cooled. However, if there is an stopping or parking on the new asphalt pavement, it is best to wait about 4 days or as long as possible. Longer waits should be designated if the area is subject to large loadings. Wait times of a week may be recommended if there is abnormally warm weather or the paving is done on a large reflective south facing wall.
Skin patching is the application of a thin layer of asphalt concrete pavement. It is often used to correct minor problems such as depressions and bumps. Skin patching is not a structural fix, but merely a temporary quick solution to a problem. It can also be used as an overlay in some cases such as pedetrian uses.
Skin patching usually uses a finer asphalt concrete pavement mix meaning it provides a smooth appearance. However, the texture of a skin patch may not match the existing old asphalt.
Skin patching should be done when the ground is not frozen or wet.
The Patchmaster is a unique machine which is specialized for quick asphalt repairs. It uses a heated pad to warm up the existing asphalt to a point where it can then be raked, new material added if needed, and compacted to form a seamless matching patch.
The patchmaster is ideal for parking lots where there is uneven surfaces around catchbasins, manhole, or oil spotted parking stalls. The patchmaster also provides s emi permanent repairs on alligatored areas.
Potholes are an annoyance to drivers and a safety hazard to pedestrians. They tend to grow quite rapidly once started.
What causes potholes?
Potholes are generally caused by poor or improper drainage. They form when water drains through the asphalt into the base through cracks in the asphalt. Wheel loading from vehicles then disperses the water in the base and the soil along with it. Eventually, dispersion of the base will become frequent enough to form deterioration of the asphalt and base causing a pothole.
How do I fix potholes?
Commonly a simple patch involving clean out of the pothole, and an asphalt concrete pavement patch is performed. However, this does not solve the underlying problem of a weak base at the specific area if there is surrounding cracks. To properly fix the pothole area, the section must be cut out and reconstructed.
Items to consider.
Potholes that are patches generally do not last very long. Without a proper cut out and hot patch, water will continue to infiltrate to the base. Pothole patching should not be completed with conventional hot mix when the ground is frozen or there is water in the pothole. Cold mix is available for this purpose. Cold mix is often used in the winter when conditions are not suitable for hot mix patching. Conventional cold mix however is often a temporary patch. For a more permanent patch, a high performance modified cold mix patch is more suitable and will give better value.
Shoving or pushing is a result of horizontal forces pushing an asphalt to form a bump. The cause of this is usually improper mix design of the asphalt or improper maintenance practises. Pushing and shoving is often seen on roadways where an overlay has been put over a section of painted lines creating an improper bond, or where an asphalt road is subjected to loading it was not designed for.
Root damage is expensive. Most people don't realize how much trees can affect asphalt. Roots tend to grow right below the asphalt surface. They may be small, but they have as much pushing power as a weed and will cause cracking in your asphalt surface.
How do I fix the problem?
To solve the problem, remove the tree and rehabilitate the affected area. If the trees are important, consider asphalt removal, root removal, and then finish with new asphalt concrete. For quick safety repairs, sometimes a simple membrane and skin patch application will suffice. At minimum, a crack seal is recommended.
As a general rule, don't place tree's close to an asphalt surface were the canopy of the tree overhangs the asphalt surface. Keep shubs, such as junipers even further away than just their canopy.
Cracking in asphalt concrete-surfaced pavements are inevitable and are the primary mode of deterioration. Neglect leads to accelerated cracking and/or pot holes, further reducing the quality and lifespan of the asphalt service. Regular maintenance, in this case, crack sealing, will add an average of five years life to deteriorated pavements at a substantially reduced cost in comparison to traditional asphalt repairs such as cutting out and hot patching and resurfacing.
Pavement is often the last item on the property managers and building owners' maintenance list. As a result, the cracks are left to deteriorate to the point where costly repairs such as cutting out and hot patching or resurfacing are required. The cost of cutting out and hot patching is normally three times more expensive than traditional resurfacing (per square foot).
MATERIALS
Two types of sealants are available to seal cracking: cold applied or hot-applied thermoplastic materials. In terms of serviceability (or lifespan/ performance), hot-applied and cold-applied are incomparable. Cold-applied sealants last only a matter of months whereas hot-applied crack sealant with rubberized polymers can provide up to five years of service.The most cost effective method for serviceability is hot-poured crack sealant with rubberized polymers. It should be noted that specialized equipment is used to correctly heat the rubberized elastomeric sealant. It requires a double jacketed hot oil kettle, and the temperature is carefully controlled during a slow melting process to bring the material to the proper tem perature. If the elastomeric crack sealant is heated incorrectly or without the proper kettle, the material is burned causing oxidization and premature failure. Unfortunately some contractors use a roofing kettle or propane torch to heat the sealant material (which burns it) and this type of equipment is not appropriate.
PREPARATION OF ASPHALT FOR CRACK SEALING
The crack itself must be cleaned and heated with a hot jet air lance, which does not expose the road surface to direct flame, thereby damaging the asphalt. Preparing the cracks are an important part of the sealing procedure. Compressed air units (hot air jet lance) are the most desirable for cleaning the cracks, removing dust, debris, loosened fragments and drying the crack channels.
Routed crack sealing is recommended whenever possible. Crack cutting or routed crack sealing is recommended to allow the sealant a good reservoir to bond. If the cracks are not large enough in which to place the sealant, it will not allow the sealant to bond. If not enough sealant is used, it will not protect the asphalt concrete from water penetration, the main cause of deterioration in asphalt surfaces.
APPLYING THE SEALANT
Over banding ensures the best possible bond and that is achieved by striking the surface with a special tool after applying the sealant. After the sealant is applied a blotting material such as limestone dust or sand is applied to protect the uncured crack treatment materials and prevent tracking. Once the crack is blotted traffic can resume immediately.
Ravelling is the loss of asphalt pavement from the surface, generally due to oxidation of the asphalt binder and chemical reaction. Raveling is a natural aging process of asphalt pavement from weathering. Chemical spills from vehicles can advance this process and create holes in the asphalt. Parking lots are highly prone to chemical raveling.
To prevent raveling, a seal coat is applied. The seal coat will protect the asphalt from oxidizing and chemical spills.
Why should I seal coat?A seal coat is a protective layer applied to the surface of asphalt concrete pavement. It protects against moisture infiltration, oxidation from weathering, and chemical spills. In addition, a seal coat provides that new black look to asphalt pavement, rejuvenating the properties appearance and therefore increasing the property value.
If you have significant patching on your asphalt with colour variations, seal coating will help blend the patching to make your asphalt look more uniform.
Dollar wise, seal coating will reduce the amount of maintenance work required and extend the life of the pavement. This means beautification by means of asphalt overlays can be postponed or even eliminated. In equivalent terms, seal coating is 1/7th the cost of resurfacing. With proper small maintenance and sealing, a 20 year seal coating program is equal to one application of resurfacing. Over 20 years without sealing, an asphalt overlay may require grinding and reapplication. No matter what, you end up ahead with seal coating.
How long does it take to dry?
Factors that affect the dry time include thickness of application, humidity, wind speed, and temperature. During warmer summer months, seal coats in the sun can dry in as little as one hour. However, on damp humid nights, seal coats may take up to 24 hours to dry.
How long does it take to cure?
Just because seal coat is dry to the touch does not mean it has cured. Seal coat does take some time to cure and until then the seal coat is softer and more susceptible to tire abrasion. Curing times vary depending on weather and thickness, but generally an average rule is 2 to 3 days before wheel marking on fresh seal coat will subside. This is not to say the seal coat will peel off while it’s curing, but there may be some wear showing on the aggregate surface.
When should I apply seal coat and how often?
Once new asphalt has been laid, a seal coat should be applied 3 to 5 years later. If you have a commercial or industrial business with oil spotting and spills in parking stalls you may want to consider seal coating once the surface oils of the fresh asphalt are no longer visible in approximately 6 months time. Once applied, it should be recoated every 3 to 5 yrs, depending on traffic volumes and wear.
The seal coat looks like it is wearing off, why?
Seal coating will wear down at different rates depending on the mechanical abrasion activity of the traffic. Snow plows and winter sanding will often accelerate the wear. The seal coat will wear off on the aggregates within the asphalt mix that vehicle tires cross over. However, this does not mean the seal coat is no longer effective. Seal coating benefits come primarily from the sealing of the asphalt binder surface, not the surface course of exposed aggregate. Sealant looking worn down or missing may still be present between the aggregate and therefore will still be providing chemical and ultraviolet protection to the asphalt binder that holds the pavement together.
Recoats of sealant will often require a fog coat on areas of high wear and a reseal will last longer than the original seal.
What’s involved in a recoat?
A recoat is similar to the original application, however it may require significantly less priming (fog coat) and may not have to be as thick in areas of less wear. This said, a reseal may run as low as 60% of the original initial sealing cost.
What about pavement cracking?Seal coat should not be expected to fill visible cracks or prevent existing cracks from spreading. Seal coat will seal micro fractures or surface stress cracking but it can not structurally repair asphalt. Crack sealing is the most cost effective repair method for asphalt preservation. Roaron Construction can provide total pavement maintenance services. We use only high quality municipal grade or better rubberized crack sealants.
Is seal coat slippery?
Seal coating will reduce the friction of asphalt pavement. The sealed asphalt will not be slippery to where a vehicle will lose traction but a review on steep sloped sections should take place prior to sealing. The seal coat applied is embedded with sand or sand like material to increase traction characteristics. There is no cause for concern in regards to pedestrian traffic.
How thick does it go on?
Seal coating will go on thick, approximately 2mm. As it dries and the water or solvent leaves the product it will cure to a thickness of approximately 0.5 to 0.9 mm thick.
Traffic Markings?
Your road and parking lot lines will be covered from a seal coat application. The seal coat will stick to the existing road markings very well. Repainting the lines are not a problem as the existing lines once coated have a relief outline texture which is easily visible for repainting.
Why latex?
Latex, an expensive additive is often recommended for areas of high use. Latex will increase the bonding ability and flexural strength of the sealant and thereby increase the overall lifespan of the product.
Are there different types of sealers?
Yes. There are solvent carried and water carried sealants. Each can have different properties and be suitable for different applications. There are different grades to suit varying client demands and budgets. Roaron Construction never uses bulk economy grade sealants and will provide other specialty sealers for different surface types and usage.
To protect and beautify your investment it is critical to select the proper sealer to safeguard the structure.
Epoxy or Urethane Injection
Urethane or epoxy injection is used to seal hairline cracks in concrete. The materials and methods of application can vary which directly influences the price.
Why is epoxy so expensive?
Epoxy is an expensive material to use; however, when applied correctly, it can be a very good construction material for sealing and bonding. The large expense to epoxy work is the preparation. The bonding capabilities is the primary focus of an epoxy material and as so, the preparation for the bond is critical. A fair bit of labour is often involved in preparation and at times, epoxy work is required in restricted places or awkward places to get to. In addition, epoxy can be very expensive, up to $800 per gallon.
How durable is epoxy?
Epoxy is very durable and strong. Most all epoxies are stronger than concrete, twice as strong is not uncommon. In addition, the flexible properties of epoxy can be greater than concrete. Epoxy is a chemically controlled product which can be adjusted to suit the needs of the application.
Epoxy vs Urethane - The Differences
Which one to use? Epoxy provides a structural bond that is stronger than the original concrete. Urethane is used when the problem is water related rather than structural.
Another waterproofing advantage urethane has over epoxy is that flexible urethane tolerates minor building movement.
To protect concrete structures, it is critical for building owners to recognize that concrete must be protected through the application of an appropriate sealer. Some primary reasons for sealing a concrete structure include:
Preventing water ingress
Inhibit carbonation
Provide waterproofing to cracked structures
Improve Aesthetics
To protect and beautify your investment it is critical to select the proper sealer to safeguard the structure.
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