Materials & Research Winter Workshop February 19, 2014

Binder Grades / Mix Types / Lift thickness A Brief Where, What, When, and Why

Types of Binder Grades We currently use 3 binder grades 64-22 70-22 76-22 Each binder grade has a purpose and a place based on the traffic characteristics on the road, one is not better than the other Always ask M&R for a recommendation to make sure you are not spending more money than you are getting benefit for.

When is a 64-22 used? When there are low to moderate volumes of trucks When the speed of the trucks is considered “fast” Roads that are typically fine with a 64-22 binder grade include: Subdivision Streets, Local Roadways, Some minor arterials, shoulders of mainline roads, etc.

When is a 70-22 used A 70-22 is considered when there are more than 10,000,000 ESALS (not ADT) on the roadway There are high volumes of fast moving trucks Roads that usually get a 70-22 mix include: Rt 13, Rt 1 (in non congested areas)

When is a 76-22 used? A 76-22 mix is considered when there are high volumes of slow moving trucks. If there is a lot of stopping and starting of traffic (i.e. congestion, intersections) Examples of Areas that would need a 76-22 include: Roads near plants with heavy equipment accessing the roadway, Toll Plazas, Stop Lights

Carbonate v Non Carbonate Stone Non- Carbonate stone is more resistant to polishing than carbonate stone. The use of Non-Carbonate stone is beneficial in areas where: The ADT is greater than 8000 vpd AND the speed limit is greater than 35 mph There are known skidding problems in the area

What gyrations? The gyrations of the mix is selected based on the traffic that is on the roadway. The properties of the mixes are slightly different to accommodate for the needs of the road. You will only see two gyrations used in DE 115 is used in areas where the ESALS (not ADT) are between 0 and 300,000 160 is used in areas where the ESALS (not ADT) are > 300,000

Mat Thickness The minimum and maximum lift thicknesses that are acceptable for asphalt concrete are based on recommendations and experience. If a material is being substituted for another (i.e. B is used for BCBC) the contractor should be allowed to place that material in BCBC lift thicknesses)

C Mix There are 3 different sizes of C mix and each has a different minimum and maximum lift thickness. 9.5mm (standard) Min lift thickness = 1.25” Max lift thickness = 2: 4.75mm Min lift thickness = 0.5” Max lift thickness = 1.25” 12.5 mm Min lift thickness = 1.5” Max lift thickness = 2.5”

B Mix and BCBC B mix* BCBC Min = 2.25” Max = 4” *The exception to this rule is when B is being paid for as BCBC. Then the mix can be placed in lifts up to 6” BCBC Min = 3” Max = 6”

Any Questions???