What is an asphalt overlay?
Asphalt overlay is an affordable solution to repair and extend the life of a roadway without total reconstruction.
Overlays consist of adding additional inches of asphalt over the existing surface or using a mill-and-fill technique that removes some of the existing asphalt before placing new asphalt.
The moment the asphalt surface starts to age, there is a high chance that it will start to crack and become unstable. An asphalt overlay can restore the ability of the surface to handle all forms of heavy traffic on its sealed and smooth surface. Dust and loose stones from the old asphalt will also be minimized and covered beneath the overlay. This work can help reduce noise levels, enhance ride quality, and extend the life of the roadway.
The process of overlaying starts with sealing cracks and removing damaged asphalt areas, followed by a thin layer of asphalt. An asphalt overlay doesn’t require any curing time, so there are only minor traffic delays.
What is a slurry seal?
A slurry seal is the application of a mixture of water, asphalt emulsion, aggregate (very small crushed rock), and additives to an existing asphalt pavement surface. The placement of this mixture (“slurry”) on existing pavement is intended to seal the pavement surface to prevent water from infiltrating the substructure and causing permanent damage to the road.
Slurry seal is applied in order to help preserve and protect the underlying pavement structure and provide a new driving surface. Roads chosen for slurry seal applications generally have low to moderate distress and narrow crack width.
The asphalt emulsion and aggregates are mixed in a truck that distributes the slurry over the pavement. Workers with squeegees follow behind and assist in spreading the mixture.
What is a chip seal?
A chip seal is the application of a special protective surface to an existing pavement.
Chip seal is used to:
- keep water from penetrating the road surface.
- fill and seal cracks and raveled surfaces of old pavement.
- provide an anti-glare surface during wet weather and an increased reflective surface for night driving.
- seal the pavement surface - minimizing effects of aging.
- provide a highly skid-resistant surface, particularly on wet pavement.
A dump truck full of chips (gravel) locks on to the chip spreader and is pulled backwards. A thin layer of liquid asphalt is sprayed down in front of the chip spreader.
The cost of chip seals is 15 percent of the cost of asphalt overlays.
What is a mill and fill?
Milling and filling is the process of grinding asphalt with a milling machine, removing the debris, and installing new asphalt using a paver.
It is a more permanent fix than simply placing asphalt in potholes.
What is a safety edge?
A safety edge is a technique applied at the pavement edge to form a 30-degree angle that reduces tire scrubbing when a vehicle has inadvertently drifted beyond the roadway. It helps the driver self-correct and get back on the roadway without over-correcting.
Pavement edge drop-offs (height differences between a paved road and the adjacent graded material) have been linked to crashes. Safety edges are an effective solution to mitigate pavement edge-related crashes.
Safety edges are created with a commercially available attachment mounted on asphalt resurfacing equipment. The attachment acts as a screed extension. As the asphalt is extruded, it confines the asphalt into the desired 30-degree shape.
What is a rumble strip?
Rumble strips are a road safety feature involving pavement indentations that cause a tactile vibration and audible rumbling when driven over to alert drivers of potential danger.
Rumble strips are effective (and cost-effective) at reducing collisions due to inattention.
There are several different ways to install rumble strips. They can be rolled into newly laid asphalt pavement while it is still warm and moldable or milled into existing hardened asphalt or concrete roads.
What is a guardrail?
A guardrail is a structure designed to prevent an errant vehicle from hitting a roadside obstacle (signs, structures, culvert inlets, utility poles, trees, rock outcroppings) or running off the road into an embankment, ravine or oncoming traffic.
Modern installations of guardrail are designed to allow the guardrail to safely redirect the vehicle back onto the roadway at a somewhat shallow angle.
What is an Americans with Disabilities Act (ADA) ramp?
Ramps are an inclined plane installed where required by the Americans with Disabilities Act, such as on sidewalks at street intersections.
Ramps permit wheelchair users, as well as people pushing strollers, carts, or other wheeled objects, to more easily access the sidewalk.
Ramps must be carefully designed in order to be useful and meet applicable specifications for width and slope.