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Posts Tagged ‘Raveling’

Tis’ The Season of Sealcoating

Friday, October 14th, 2011

Summer is long gone and winter is right around the corner. You know what means, right? No? Well, it means that this is your last chance to sealcoat your parking surface before the weather gets too cold. Sealcoating is a widely used and accepted preventative measure that helps safeguard your parking lot against the harsh effects of gas, oil, salt, weather conditions and oxidation. A proper seal is important for avoiding parking lot cracks and potholes.

So if you think it may be time for a fresh coat (should be done every 2-4 years), contact your local asphalt pavement specialist. While you can attempt a sealcoating on your own, a do-it-yourself sealcoat is never the best idea. You should put your trust in a company with a proven track record of success, professionalism, like PTG Enterprises.

What types of problems can I expect if I do not sealcoat?

Raveling is the most common problem caused by unsealed asphalt pavements. Raveling is the loss of aggregate from the asphalt pavement surface. This results from an “abrading” action of vehicle wheels and oxidation from the sun. Raveling will appear as a rough texture on the pavement surface, or “craters” in the surface left as the coarse aggregate pops out of the surface. Raveling is most evident in the parking lots that have a gray or white color to the asphalt surface. This indicates the asphalt binder has dried out and the surface is now brittle. Even though raveling is aggravated by vehicle traffic and the sun, it is a material problem, not a structural defect, of the pavement system.

If you have any additional questions, contact PTG Enterprises aka My Pavement Guy by calling 410-636-8777or click heretoday!

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Sources:

‘Tis the Season of Football and Driveway Sealcoating WolfPaving.com

The Deterioration of Asphalt Pavement and its Causes

Thursday, July 21st, 2011

Even the most durable paved surfaces, like asphalt pavement, are susceptible to deterioration, distress, and cracking. However, knowing what causes these problems can help you prolong the life of your asphalt. This article from PaveManPro.com can help. It outlines the major causes of pavement deterioration.

Overtime, the materials that make up asphalt begin to break down and become more easily affected by the elements: rain, sunlight, snow, etc. Furthermore, the liquid binder that holds the asphalt together begins to lose its natural resistance to water, allowing liquid to seep into the pavement. Once this happens, the surface can quickly be affected.

Yet, while pavement will naturally breakdown over time, there are a few outside factors – poor construction or human error – that may speed up this process, causing premature deterioration.

The factors leading to asphalt deterioration include:

•      Insufficient or improperly compacted base below the asphalt

•      Over or under compaction of asphalt

•      Improper temperature of asphalt when applied

•      Poor drainage

•      Water – over time and especially without proper maintenance water penetrates the asphalt, washes out the base underneath it, causing it to crack, break down and collapse.

•      Sunlight – Oxidation breaks down and dries out the once flexible liquid asphalt that holds the aggregate together. This causes raveling and shrinking cracks, which allow water to penetrate beneath the surface.

•      Chemical/ petroleum exposure – the introduction of chemicals to asphalt, including gas and oil, can soften the asphalt and cause it to break down more rapidly.

When asphalt pavement is constructed and maintained properly it wears out slowly and can last up to 25 years or more. Proper maintenance is key to protecting it from the external factors that wear it out.

If you notice your driveway, parking lot, or any pavement displaying any signs of deterioration, it is probably time to call a professional to patch your asphalt and prevent further damage. Do not put this off and let small cracks become big problems. It is far better to pay for a little patching now than to have to pay for a total re-paving down the road.

If you have any questions, contact PTG Enterprises aka My Pavement Guy by calling 410-636-8777 or click here

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Identifying Pavement Defects

Thursday, July 14th, 2011

It is a well-known fact that water and asphalt do not mix. Harsh weather can cause asphalt to become distressed, crack, and eventually fail. This article from PaveManPro.com outlines the 13 ways in which weather adversely affects your pavement.

1.    Alligator Cracking: Alligator cracking is a load associated structural failure. The failure can be due to weakness in the surface, base or sub grade; a surface or base that is too thin; poor drainage or the combination of all three. It often starts in the wheel path as longitudinal cracking and ends up as alligator cracking after severe distress.

2.    Block Cracking: Block cracks look like large interconnected rectangles (roughly). Block cracking is not load-associated, but generally caused by shrinkage of the asphalt pavement due to an inability of asphalt binder to expand and contract with temperature cycles. This can be because the mix was mixed and placed too dry; Fine aggregate mix with low penetration asphalt & absorptive aggregates; poor choice of asphalt binder in the mix design; or aging dried out asphalt.

3.    Longitudinal (Linear) Cracking: Longitudinal cracking are cracks that are parallel to the pavements centerline or laydown direction. These can be a result of both pavement fatigue, reflective cracking, and/or poor joint construction. Joints are generally the least dense areas of a pavement.

4.    Transverse Cracking: Transverse cracks are single cracks perpendicular to the pavement’s centerline or laydown direction. Transverse cracks can be caused by reflective cracks from an underlying layer, daily temperature cycles, and poor construction due to improper operation of the paver.

5.    Edge Cracks: Edge Cracks travel along the inside edge of a pavement surface within one or two feet. The most common cause for this type of crack is poor drainage conditions and lack of support at the pavement edge. As a result underlying base materials settle and become weakened. Heavy vegetation along the pavement edge and heavy traffic can also be the instigator of edge cracking.

6.    Joint Reflection Cracks: These are cracks in a flexible pavement overlay of a rigid pavement (i.e., asphalt over concrete). They occur directly over the underlying rigid pavement joints. Joint reflection cracking does not include reflection cracks that occur away from an underlying joint or from any other type of base (e.g., cement or lime stabilized).

7.    Slippage Cracks: Slippage cracks are crescent-shaped cracks or tears in the surface layer(s) of asphalt where the new material has slipped over the underlying course. This problem is caused by a lack of bonding between layers. This is often because a tack coat was not used to develop a bond between the asphalt layers or because a prime coat was not used to bond the asphalt to the underlying stone base course. The lack of bond can be also caused by dirt, oil, or other contaminants preventing adhesion between the layers.

8.    Pot Holes: Small, bowl-shaped depressions in the pavement surface that penetrate all the way through the asphalt layer down to the base course. They generally have sharp edges and vertical sides near the top of the hole. Potholes are the result of moisture infiltration and usually the end result of untreated alligator cracking. As alligator cracking becomes severe, the interconnected cracks create small chunks of pavement, which can be dislodged as vehicles drive over them. The remaining hole after the pavement chunk is dislodged is called a pothole.

9.    Depressions (bird baths): Depressions are localized pavement surface areas with slightly lower elevations than the surrounding pavement. Depressions are very noticeable after a rain when they fill with water.

10.  Rutting: Ruts in asphalt pavements are channelized depressions in the wheel-tracks. Rutting results from consolidation or lateral movement of any of the pavement layers or the subgrade under traffic. It is caused by insufficient pavement thickness; lack of compaction of the asphalt, stone base or soil; weak asphalt mixes; or moisture infiltration.

11.  Shoving: Shoving is the formation of ripples across a pavement. This characteristic shape is why this type of distress is sometimes called wash-boarding. Shoving occurs at locations having severe horizontal stresses, such as intersections. It is typically caused by: excess asphalt; too much fine aggregate; rounded aggregate; too soft an asphalt; or a weak granular base.

12.  Upheaval: Upheaval is a localized upward movement in a pavement due to swelling of the subgrade. This can be due to expansive soils that swell due to moisture or frost heave (ice under the pavement).

13.  Raveling (very porous asphalt): Raveling is the on-going separation of aggregate particles in a pavement from the surface downward or from the edges inward. Usually, the fine aggregate wears away first and then leaves little “pock marks” on the pavement surface. As the erosion continues, larger and larger particles are broken free and the pavement soon has the rough and jagged appearance typical of surface erosion.  There are many reasons why raveling can occur, but one common cause is placing asphalt too late in the season. This is because the mixture usually lacks warm weather traffic which reduces pavement surface voids, further densification, and kneading of the asphalt mat. For this reason raveling is more common in the more northern regions(snow belt).

If you notice your pavement displaying any of the above problems, it is probably time to call a professional to patch your asphalt and prevent further damage. Do not put this off and let small cracks become big problems. It is far better to pay for a little patching now than to have to pay for a total re-paving down the road.

If you have any questions, contact PTG Enterprises aka My Pavement Guy by calling 410-636-8777 or click here

Check us out on Facebook and Twitter as well!