Story Source: AWPA
It happens to us all. We’re on a relatively smooth ride and suddenly- BAM. Your vehicle dips a few inches and you’re left wondering how much damage has been done on your brand new tires. Chances are, you just hit a pothole. You’ve heard the term and if you’re like most people, you detest them. Potholes are certainly a nuisance, but they can often be dangerous and will require fast repair.
But what are they? And how do they get fixed?
What causes a pothole?
Potholes are created when the top layer of pavement and the material beneath—called the base or sub-base—cannot support the weight of the traffic. Two factors are always present in such a failure: TRAFFIC and WATER. The “gestation period” for a pothole includes:
1) Snow-melt or rain seeps through cracks in the pavement and into the sub-base; if the moisture cannot adequately drain away from the sub-base and soil underneath, it becomes saturated and soft.
2) Trapped moisture is subjected to repeated freeze/thaw cycles–and with each occurrence the expanding ice lifts and cracks the pavement more. The passing traffic weakens the pavement, cracking it further.
3) As temperatures rise and the ice melts, a void is left under the pavement. This void collects more water, and during the next freeze, the void will enlarge.
4) Vehicles driving over the weakened pavement pound it until the surface breaks and collapses into the void below, thus creating a pothole.
Why are they called potholes?
According to the late trivia expert and syndicated columnist L. M. Boyd, pottery makers in l5th and l6th century England would take advantage of the ruts that wagon and coach wheels gouged into roads. Anxious for a cheap source of raw materials for making clay pots, the potters would dig into the deep ruts to reach clay deposits underneath.
Teamsters driving wagons and coaches over those roads knew who and what caused these holes and referred to them as “potholes.”
What affects pavement life?
Pavement life is influenced by many factors: vehicle loading (axle loads, tire pressure and gross vehicle weight [GVW]), traffic volume and mix, environmental conditions, topography, subgrade condition, initial pavement design and construction practices, maintenance activity and pavement age.
Traffic volume has increased significantly and this trend will continue —but few new lane-miles have been added to the nation’s highway, road and street network and are not expected to keep pace with the increased demand.
The decision and capability to patch potholes is influenced by: current weather; traffic conditions; imminent scheduled roadway construction; major maintenance work or utility work in the roadway; availability of personnel, equipment, and materials, and the demands of the traveling public.
How are potholes repaired?
Pothole patching is performed either as an emergency repair during harsh conditions or as routine maintenance scheduled for warmer and drier periods. Typically, emergency repairs are done only when a pothole presents a substantial safety or traffic operational problem and must be urgently corrected.
For example, a large pothole on a major arterial has contributed to collisions by causing drivers to swerve to avoid or lose control after hitting it. Or, one or more large potholes hinder the flow of traffic causing unusual slow-down and congestion. Potholes near activated traffic signals may expose embedded loop sensor wires, and when they break, the signals will not be responsive to traffic demands.
Emergency repairs usually are done in heavy traffic and can be a safety risk to maintenance workers. Repairs that are more permanent can be scheduled for times when weather and traffic are more conducive to safe operations.
There are a number of standard pothole repair methods used for any asphalt paved street or road, but here is a demonstration of how FastPatch products, a division of WVCO, can be used to repair a common pothole.
To learn more about FastPatch and what we can do for you, visit fastpatchsystems.com.