A newly published industry report offers asphalt producers a practical way to better account for the environmental benefits of warm mix asphalt in Environmental Product Declarations (EPDs).
The framework provides a more accurate method for measuring fuel consumption during asphalt production by recognizing that warm mix asphalt is produced at lower temperatures and therefore requires less energy than traditional hot mix asphalt.
The report could help asphalt producers more effectively document sustainability improvements without adding significant reporting burdens.
Why Current EPD Reporting Falls Short
Environmental Product Declarations are increasingly used to measure and communicate the environmental impact of construction materials. However, current reporting practices have limitations when it comes to asphalt production.
Under existing Product Category Rules, asphalt plants report burner fuel consumption using a 12-month plant-wide average. This means that both warm mix asphalt (WMA) and hot mix asphalt (HMA) are assigned the same production-stage energy impacts if they are produced at the same facility.
As a result, the fuel savings achieved by producing warm mix asphalt at lower temperatures are not reflected in EPD calculations.
For producers investing in more sustainable production methods, this approach can underestimate the environmental advantages of warm mix technologies.
New Method Uses Production Temperature Data
The report introduces a thermodynamics-based framework that allocates burner fuel consumption according to the actual production temperature of individual asphalt mixes.
Rather than relying solely on annual plant averages, the method evaluates how much energy is required to produce specific asphalt mixtures.
The framework considers several key factors involved in asphalt production, including:
- Heating virgin aggregates
- Heating reclaimed asphalt pavement (RAP)
- Drying materials during production
- Heat losses from exhaust gases
- Heat losses from plant equipment
By accounting for these variables, the framework can estimate fuel consumption more accurately for different mix types and production temperatures.
No Additional Equipment Required
One of the most practical benefits of the framework is that it relies primarily on information that asphalt plants already collect during normal operations.
Producers can use existing data such as:
- Annual burner fuel consumption
- Production tonnage
- Asphalt mix temperatures
- Mix design information
- Moisture content estimates
Because the methodology uses routinely collected operational data, producers can implement the approach without investing in new monitoring systems or specialized equipment.
Framework Tested Across Multiple Asphalt Plants
Researchers validated the model using fuel consumption data collected from 10 asphalt plants producing both hot mix and warm mix asphalt.
The evaluation included several plant configurations and operating conditions across multiple states.
According to the report, the framework demonstrated a high level of accuracy when estimating fuel consumption for warm mix asphalt production and performed consistently across different plant types.
The results suggest that the methodology can provide reliable estimates while remaining practical for industry-wide use.
Industry Survey Shows Strong Applicability
In addition to the technical study, researchers conducted a nationwide survey involving 169 asphalt plants located in 29 states.
The survey found that most asphalt producers already maintain the operational data needed to apply the framework.
For plants that do not track specific moisture content information, the report provides a recommended default value that can be used without significantly affecting fuel savings estimates.
This flexibility makes the framework accessible to a wide range of asphalt producers regardless of plant size or configuration.
Supporting More Accurate Sustainability Reporting
As sustainability reporting becomes increasingly important in construction and infrastructure projects, accurate environmental data is becoming a competitive advantage for material producers.
Warm mix asphalt technologies have long been recognized for reducing production temperatures and lowering energy consumption. However, existing EPD reporting methods have made it difficult for producers to demonstrate those benefits quantitatively.
The new framework addresses that challenge by providing a credible and practical approach for incorporating temperature-based fuel savings into environmental reporting.
A Step Forward for Sustainable Asphalt Production
The proposed methodology gives asphalt producers a low-effort way to improve the accuracy of their Environmental Product Declarations while highlighting the environmental benefits of warm mix asphalt.
By better aligning fuel consumption calculations with actual production conditions, the framework could help promote more sustainable asphalt manufacturing practices across the industry.
As infrastructure owners and project teams place greater emphasis on sustainability metrics, tools that improve environmental reporting are likely to play an increasingly important role in material selection and project planning.
