by Connie Houk, PE
Car repair shops love potholes! The rest of us, not so much.
So, how do we prevent them? The answer is simple. If there is no water trapped under the road bed to freeze, there are no potholes. The solution, however, is a complex mixture of design, materials, maintenance and management practices.
Crack Sealed Pavement
Chip Sealed Pavement
Rain water and moisture get under a road surface through cracks in pavement. Water pools under the pavement, gravel and sand underneath. The moisture freezes and expands. This pushes the pavement up. As the temperature rises, the ground lowers back down but the pavement stays raised . . . until a vehicle runs over it. The pavement then cracks and falls into the void created when the ground settled back down. The strength or quality of the gravel and sand beneath pavements helps prevent it from holding water and thus cracking. So, to prevent potholes, a road must have a strong gravel and sand base that allows water to percolate through it quickly.
Engineers, contractors, inspectors, aggregate and pavement producers, public works maintenance staff, managers, and elected officials all play a key role in road quality. In the last 15 years, we have learned a lot about managing road systems by applying the principles of Pavement Management (PM). PM aims to produce the lowest life-cycle cost of a given road by applying the right mix of design fixes (maintenance, repair, rehabilitation or replacement) at the right time. Applying the wrong fix doesn’t help the pavement’s life or an agency’s budget—that’s why we recommend using Pavement Management principles.
Intuitively, it makes sense to fix the worst roads first. PM research shows, however, that is the wrong way to manage a road system unless you have an unlimited budget because it is so expensive. It’s actually more cost-effective to invest in effective pavement management techniques on your better roads that still have life left in them before spending your whole budget on your worst roadways. For example, sealing pavement cracks is a very cost-effective pavement management technique, as it prolongs the life of an already good road surface.
Sample Color-Coded Condition Rating Map
One Prein&Newhof client, the Canadian Lakes Property Owners Association (CLPOA), owns over 40 miles of private paved roads within its resort community in Mecosta County. By developing and implementing CLPOA’s pavement management plan, they were able to reduce their streets budget by approximately 30% after two years. We introduced maintenance fixes to their annual plan along with continuing their traditional overlay plan. This pavement management plan allows us to rehabilitate the worst roads, address associated problems on the roads, and prolong the life in their already good pavements.
A good pavement management plan includes five steps:
- Inspect and rate the condition of every road on a given cycle during the spring season.
- Map the roads, and color-code the condition ratings.
- Develop your long-term pavement management plan based on condition ratings coupled with opportunities to improve other infrastructure within given projects.
- Develop a long-term cash-flow schedule that best matches your needs with available funding.
- Adopt and work your plan, making revisions as-needed.
Spring is the best time of the year to get your pavements evaluated. Once the temperatures get too warm, your pavement cracks may not be as noticeable.
To learn how using pavement management principles in your community can help you, please contact me.