PT-3: Warm Mix Asphalt
3 points
Goal
Reduce fossil fuel use at the hot mix asphalt plant, decrease emissions at the plant, and decrease worker exposure to emissions during placement.
Requirements
Reduce the mixing temperature of hot mix asphalt by a minimum of 50°F from that recommended as the mixing temperature by the asphalt binder supplier. Mixing temperature shall be measured as the temperature of the mixture as it exits the mixing drum (for drum plants) or pugmill (for batch plants). This reduced temperature mix must comprise a minimum of 50% of the total project pavement (hot mix asphalt or portland cement concrete) by weight.
Documentation
- A copy of the WMA mix design should be submitted. The mix design should have
the following items highlighted:
- Name of WMA technology used
- If an additive was used, percentage by weight of binder or by weight of mix
- Total tons of high-type pavement on the project, including Portland cement
concrete and asphalt concrete (hot, warm and cold mix)
- Total tons of WMA pavement used
- WMA mix temperature as it exits the drum (drum plant) or pugmill (batch plant)
- Recommended asphalt binder mixing temperature from the asphalt binder
supplier.
- Total fuel used in the burner per ton of WMA
- Total fuel used in the burner per ton of HMA if HMA was used. If HMA was not
used, a general plant average is acceptable.
- A photo taken during placement of the mix, clearly labeled to identify the WMA.
Public commentary on credit PT-3
We will accept the following alternatives to earn this credit for non-HMA projects:
Select an ENERGY STAR® certified cement production plant for cementitious materials used on the project. To be ENERGY STAR® certified the plant must score in the top 25 percent based on the EPA National Energy Performance Energy Rating System.
OR
Burn recycled oil, waste materials, or other fuel saving technologies in HMA plant or cement production plant to reduce conventional fuel usage by a minimum of 25 percent.
To LionelL: Agreed that this credit is only for asphalt. It should be results-based and the relevant result is reduced energy use in materials production in this case (there are other advantages of WMA but we will stick with energy use for now).
We are working on a Custom Credit that also includes Energy Star certified cement plants and using waste fuel. Your suggestion of a certified ready-mix plant is also a way to achieve this broader goal. So...look for the custom credit when we post it and look for a better version of this credit in Version 2.0.
This provides credit for asphalt pavement only. I suggest changing the name of the credit to Reduce Fossil Fuel Use and provide a criteria for concrete to meet also. One suggested criteria is concrete with energy footprint 15% below the national baseline. NRMCA has developed a rating system for concrete plants and a carbon/energy calculator. I suggest changing the requirements to this credit as follows:
PT-3: Low Energy Pavements
Goal
Reduce embodied energy of pavements and decrease carbon emissions.
Requirements - Meet the following:
1. Reduce the mixing temperature of hot mix asphalt by a minimum of 50°F from that recommended as the mixing temperature by the asphalt binder supplier. Mixing temperature shall be measured as the temperature of the mixture as it exits the mixing drum (for drum plants) or pugmill (for batch plants). This reduced temperature mix must comprise a minimum of 50% of the total project pavement (hot mix asphalt or portland cement concrete) by weight.
2. Concrete shall be supplied from a concrete plant that can demonstrate a carbon footprint and embodied energy 15% below the national averages as established in the National Ready Mixed Concrete Association's (NRMCA) Sustainable Concrete Plant Guidelines (http://www.nrmca.org/sustainability/Certification/PlantCertification.asp). Carbon footprint and embodied energy shall be calculated using the NRMCA Carbon Calculator (http://www.nrmca.org/sustainability/Certification/PlantCertification.asp).
OR
Concrete shall be supplied from a concrete plant that is an NRMCA Sustainable Concrete Plant Certified Silver.
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The Greenroads Team
