By: John Davis
Asphalt pavements by asphalt sealing columbia md are everywhere. You drive on them, walk on them and live your life near them. They make up the roadways and parking lots we use everyday and they provide a simple and inexpensive means of providing traffic-bearing surfaces to our society. Asphalt is without doubt the superior pavement surface in all areas except one; noise control. Noise pollution from vehicle tires rolling over these surfaces can be intrusive and annoying much like having to listen to loud music played in a car next to you at a stoplight. This annoyance has prompted engineers in several states to implement innovative asphalt paving techniques that can reduce tire/pavement noise levels by as much as 9db(A), thus reducing the annoyance level experienced by nearby communities.
Asphalt pavements are made up of layers of aggregate, binder (asphalt cement) and reinforcing system. The method by which these materials are placed, compacted and finished will determine its long term performance characteristics. As with any construction activity there are many pitfalls that can be avoided by thoroughly planning your project before you begin. Over the course of my work career I have seen contractors make numerous mistakes on their paving projects which could have been prevented by proper planning. Let's take a look at some typical problems associated with asphalt pavement construction so you can avoid them on your next job!
A common mistake is failure to remove all existing/old pavement material within the proposed limits of the new asphalt wearing surface. This typically occurs when driveways are opened up to provide access to existing asphalt or concrete pavements that are being repaired or replaced. The intent of the contractor is to remove his proposed work limits which will include the driveway repairs/reconstruction, but he fails to do this, leaving behind old pavement material(s) down to the original base course. This oversight can cause problems with future construction because openings dug through these areas can be within inches of an underground utility pipe, culvert, drainage line etc.(see Figure 1). All excavations must be thoroughly evaluated before backfilling and compaction begins.
Figure 1: Areas left under excavation for any reason should have all other materials removed down to the approved base course before compacting occurs. If this does not occur it can result in utility conflicts that can potentially cost thousands to resolve.
Another pitfall we see is the placement of construction equipment and materials too close to proposed work limits. Asphalt pavements must be constructed and finished within specific tolerances based on the project type (commercial or residential). If these limits are not followed you will end up with a substandard wearing surface (see Figure 2) that will require significant rework before it can be used by traffic. The "typical" answer given is "we didn't know any better". This may be true, but as a contractor who has been hired by your customers to provide a service they expect the best possible performance from every aspect of your work! Proper planning and consultation with those familiar with.