Crackfilling- Asphalt Vs. Nature

Crackfilling

Asphalt Vs. Nature 

Deterioration of pavement is natural.  It’s natural because over time the materials that make up the asphalt begin to break down and become more affected by elements such as rain, sunlight, and chemicals that come into contact with the pavement surface.  The liquid asphalt binder that is the “glue” of the pavement begins to lose its natural resistance to water, allowing it to penetrate into and underneath the pavement. Once this happens, the entire surface of your pavement can quickly deteriorate.  

All pavement failure starts with a crack.  There are various elements that contribute to worn out asphalt and must be stopped before it’s too late.  Just as you paint a new house to protect it from these elements, asphalt must also be protected to maximize its lifespan.  Proper attention to cracks will help prevent further asphalt deterioration and extend the wear and use of the pavement.  

The best way to handle cracked pavement is to perform a seal coat as soon as minor cracking is detected.  If that is not possible, or the cracks have grown too wide, crack sealing is a good alternative.  The use of crack sealant is a good choice for a small crack or where seal coats or overlays will be performed in the near future. The key to preserving asphalt pavement is to catch the deterioration early and perform pavement preservation techniques to eliminate or slow the damage. 

More information about crackfilling is available on our website.
www.pavesouth.com

Proper Drainage Systems

Not sure what this means?  Well, some of the most hazardous situations in your parking lot can be the result of this so let me explain.

The above equation is known as the time of concentration, or Tc.  It is the  time  in  minutes,  for  a  raindrop  to  travel  from  the most distant point in a parking lot to a concentration point (an inlet) after the beginning of rainfall.  Of course there are more equations to follow after, but the time of concentration could be considered the most vital piece of information for parking lot construction from start to finish.

The Importance of Proper Drainage Systems

Water is probably the greatest cause of distress in a paved structure.  The primary drainage function of parking lots is to convey minor storms quickly and efficiently to the storm sewer or open channel drainage with minimal impact on the vehicle/pedestrian traffic and the surrounding environment.  In addition, removing water quickly from paved surfaces will prevent water from reaching the subgrade, minimize cracks due to the weakened subgrade, and prolong the life of the pavement in a parking lot.

Site drainage is an extremely important component in the makeup of your parking lot.  Drainage in a parking area is often overlooked, but when something goes wrong, the results can be devastating.  To prevent storm water from becoming a hazard to the public and causing water damage to the structure of the pavement you should address any water issues in your parking lot immediately. When drainage issues are not attended to you can expect to see a shortened parking lot life.  Catastrophic damage can result from procrastination.

Types of Curbs and Their Advantages

In North Carolina, the type of curbs that are used do not vary much. "24" Curb and gutter" probably represents 90% of all curb installations in the state. But why is this? There are many other types of borders that might perform just as well if not better. As you travel north or south from North Carolina, the type of curb that is prevalent in each state varies. The look can differ slightly by changing the width of the pan or its inset radius, or sometimes the shape of the upright portion may vary too. In some instances there may not be a pan at all. The pan, if you don't know, is the horizontal portion of the "curb and gutter" system also referred to as the gutter.

To completely understand this situation, its important to understand what a curb is and why curbs are used. The National Ready Mixed Association defines a curb this way.

A curb, by definition, is something that restrains; an enclosing border or edging; a raised edge or margin; a wall; or as a verb, to strengthen or confine something. As most people think of curbs, they are raised strips of concrete along the edges of streets or parking lots. The benefits of curbs have been recognized since ancient times, and stone curbs were placed along the edges of traveled ways by early civilizations. Today's concrete curbs still provide many of the same benefits, and more.  http://www.concreteparking.org/curbs/index.html

Based on this definition, we can begin to list some of the benefits that curbs offer:

• Help to define water flow to points of collection such as storm drains. This reduces erosion and allows water to move at lower percentages of grade.
• Add visual appeal by providing sharp demarcations between different types of surface.
• Strengthen the edge of flexible pavement systems such as asphalt by minimizing erosion and containing the pavement subsystem.
• Protect shoulders by keeping traffic contained.
• Improve the visibility for drivers.
• Provide a protective barrier to steep drop offs.

There are other benefits to curbs but these are main reasons road authorities or owners of parking lots install curbs. However with all these benefits, shouldn't the type of curb vary by priority for a given situation? You would think so. At least I think so. 

When first arriving to North Carolina from New York State I could not understand why all the curb was the same. After all, we used to build curb to the situation. Often because of the harshness of the winters, we would add rebar , increase the thickness or put it deeper into the ground. We did valley curb, curb and gutter, upright curb, median curb and many other types of curb. On just about every job the curb detail was one of the most important details. In North Carolina, we hardly give the curb detail a second thought. Its just always the same. Why?? 

It is difficult to definitively answer this question but after having been here for 10 years now I can, at least, begin to conjecture. Perhaps it is  because 24" curb and gutter just seems to work here 95% of the time. I have seen very few situations where for one reason or another it did not work. In just about every situation across the board including mainline roads it does the job. As a result every concrete crew knows how to form and pour curb and gutter. Every curb crew with a curb machine has the standard form that meets the NCDOT spec for this curb. This brings down costs through familiarity and, in my opinion, the NCDOT and engineers throughout the state know that prices from contractors go up when they are bidding on details that are foreign to them. Over time this particular iteration of curb and gutter just seems to have won out with everybody.