Performance of the pavement structure and the travel surface are negatively affected by several factors:
- Weather (Rain, snow, sun & heat, temperature fluctuation)
- Chemical treatments for snow and ice removal
- Traffic (Volume and weight)
The challenge is to combat these factors and implement a pavement preventive maintenance program to preserve the life expectancy and enhance the safety of these surfaces.
Old strategies such as a “Worst First” approach to pavement maintenance have been proven to be ineffective. Simply paving the worst roads in the County on a yearly basis will, among other things, only increase the backlog of necessary maintenance. There simply isn’t enough money to “pave our way out of trouble”.
Henrico County is striving to utilize a Preventive Maintenance program that employs a strategy that preaches using “The Right Treatment on The Right Road at The Right Time”.
This program calls for the use of different maintenance treatments that arrest deterioration of the pavement and restore the necessary surface qualities. The pavement management program currently being used by the County will identify distresses and categorize the proper treatments for them. In turn, the same program will aid in setting up consistent and adequate funding to treat these pavements before the significant investment in the system is lost.
STREET REPAIR PROCESS
Resurfacing your road is a two phase process. Prior to slurry seal resurfacing, DPW will evaluate the pavement and perform any repairs such as crack sealing and patching. Depending upon the condition of the pavement, one or more of the following repair options may be employed.
Phase 1 (Total of 4-6 Weeks)
Asphalt Patching – Areas of pavement distress are excavated, and replaced with hot mix asphalt. This method is used in isolated areas where pavement failures extend through the road base. Asphalt patching restores the pavements integrity and capacity to support vehicle loads.
Chip Seal – This method is used to address large areas of moderate to heavy pavement (distress) cracking. It is an effective and cost efficient method of paving large areas throughout the road. The chip seal method of patching involves several steps.
- First, the pavement is primed (sprayed) with an emulsified asphalt binder. Next, the chips or small stones are broadcast throughout the area to be patched. Then a roller compacts the material to crush the stone into the pavement cracks. After approximately 10 days, a power broom sweeper removes the loose stones and prepares the surface to receive the slurry seal resurfacing. The 10 day time period is to allow the stone to set up in the asphalt binder.
- Please expect that some loose stone may remain after sweeping. A second sweeping will remove the residual stone or it will be incorporated as additional aggregate in the final resurfacing with slurry seal.
Asphalt Reclamation — As with chip seal, asphalt reclamation is an effective and cost efficient method of rehabilitating large portions or all of a road. The County is involved in two pavement recycling processes:
- Heat scarification is the process of heating the road surface to a high temperature. Metal forks are then inserted into the road which allows for the re-compaction of the asphalt. When completed a thin layer of asphalt is applied and compacted with a roller.
- The milling of a road is a process of recycling that involves a large machine that will grind the pavement into small pieces, the pavement material is loaded into dump trucks and transported to the asphalt plant for reprocessing. The product is then carried back to the job site for application back onto the roadway.
Phase 2 (Total of 2-4 Weeks)
Slurry Seal is one treatment that has been proven to extend the serviceable life of the pavement while enhancing the safety and quality of the surface. Slurry Seal is a cold mix blend of high quality aggregate, asphalt emulsion and chemical additives that control the mixture as weather conditions demand. It is a semi-liquid mixture applied approximately ½ inch thick that will require 2-3 hours to completely dry and be ready to accept traffic.
Prior to commencement of the project each resident will receive a notice detailing the plan of operation. This flier will provide information on such things as which day to expect the work to be done, how long it should take, tips on driving through the work zone and contact information for both the County and Contractor personnel.
Unlike conventional asphalt resurfacing, Slurry Seal is mixed and applied on the street by specially designed equipment. Typically, one side of a residential street will be sealed, allowing traffic to flow in the unpaved lane. Once the newly sealed surface has cured, the adjoining lane will then be sealed. It is a very quick and efficient operation that typically can complete each street by the end of the day, thus minimizing the inconvenience to residents.
Some other benefits of the Slurry Seal program include that, due to the thinner application, the loss of curb reveal is minimal. Drainage is not affected and also eliminates the need for costly pavement milling prior to application. The need to adjust manhole and utility castings is also eliminated. These preparation techniques can help increase conventional paving costs to five times the cost of Slurry Seal. This cost savings can lead to more miles of pavement being maintained.
One other consideration would be the eco-efficiency of the system. Being a
cold-applied process, Slurry Seal, from manufacturing the emulsion to transport of materials to application, requires far less energy consumption than hot-mix asphalt production. It is also a fully recyclable material.
Once the new Slurry Seal project is completed, the pavement will be uniform in appearance with a texture that will provide a safe and durable surface that will extend the life of the pavement by 5-7 years.
Links of interest:
Resurfacing Residential Roads Brochure
International Slurry Surfacing Association
National Asphalt Pavement Association