An asphalt mix design submittal is the document that shows an engineer exactly what mix you plan to place: the aggregate gradation, the binder grade and content, and the lab results that prove the blend meets the specification. Engineers ask for it because once asphalt is down, fixing the wrong mix means tearing it out. Getting the submittal right early keeps your approval, and your paving date, on track.
What a mix design actually is
A mix design is the recipe behind a specific asphalt mix. It answers a few basic questions: which aggregates go in, in what proportions, how much binder, what type of binder, and how the finished mix performs when compacted in the lab. In Florida, most surface and structural mixes are designed using the Superpave system, which ties the aggregate structure and binder to the expected traffic and climate.
The output is often called a job mix formula. It sets target values that the plant produces to, along with allowable tolerances during production.
What a typical submittal includes
Exact requirements vary by agency and project, so always read the specification. Most submittals cover the following:
Mix identification
- The mix type and nominal maximum aggregate size, for example SP-9.5, SP-12.5 or SP-19.
- The intended use: surface, structural or base course.
- The traffic level the mix was designed for, where the spec uses traffic categories.
Aggregates
- Sources of each aggregate and their proportions in the blend.
- The combined gradation, showing the percentage passing each sieve size against the spec limits.
- Aggregate properties the spec calls for, such as angularity or toughness tests.
Binder
- The performance grade, such as PG 64-22, PG 67-22 or polymer-modified PG 76-22.
- The design binder content as a percentage of the total mix.
- Recommended mixing and compaction temperature ranges.
Recycled content
- If the mix includes RAP, the percentage used and how it affects the total binder.
Volumetric properties
These numbers describe how the compacted mix is put together. Common ones include:
- Air voids: the small pockets of air in the compacted mix. Too high and water gets in; too low and the mix can rut or bleed.
- VMA (voids in mineral aggregate): the space between aggregate particles available for binder and air.
- VFA (voids filled with asphalt): how much of that space is filled with binder.
- Dust-to-binder ratio: the balance of fine material to binder, which affects durability.
Performance checks
- Moisture susceptibility testing, which shows how the mix holds up when wet. That is a real concern on the Treasure Coast, where pavement sees heavy rain much of the year.
- Any added tests the agency requires for the mix type.
Why engineers ask for it
From the engineer's side, the submittal is risk control. A few reasons it shows up in nearly every spec:
- It proves compliance before placement. Reviewing a document costs far less than removing a failed mat.
- It matches the mix to the design. A pavement section is designed around certain layer properties. The submittal confirms the mix delivers them.
- It sets a baseline for testing. Field and plant tests during the job are compared against the approved design.
- It protects the owner. Public agencies and developers need a paper trail showing the material met the contract.
How FDOT work differs
On FDOT and many local agency projects, mix designs go through the agency's own approval process, and the contract will say which designs are acceptable. Read the specification and talk to the plant early, because a mix that works on a private job may not be approved for an agency job. We produce mixes that meet FDOT specifications depending on project requirements, and you can review our standard gradations and binders on the specifications page.
Keeping the submittal from slowing the job
- Read the spec first. Note the mix types, binder grades, recycled content limits and any special tests.
- Confirm the mix with your plant before you bid. Availability is confirmed per project, and settling it early avoids a late substitution.
- Ask what documentation is available. Our on-site quality program includes documentation to support contractor, developer and municipal requirements. Ask the plant what is available for your project.
- Submit early. Engineers have their own review queues. Build review time into the schedule.
- Plan production with the plant. Lead time depends on the mix and the production schedule, so share your paving dates once the design is approved.
After approval: production matches the paperwork
An approved design only helps if production stays on target. At our Gencor plant in Vero Beach, quality control happens on site: mixes are sampled and tested during production, temperatures and consistency are monitored batch to batch, and material is checked against the specification required for each project. Catching an issue at the plant is far better than finding it in a core.
Start with the right mix
If you are working through a submittal on a project in Indian River, Brevard, St. Lucie or Martin County, start with a mix design request. Send your spec and project details through our contact page, see our services for how mix design and technical support work, or call or text (772) 494-6077.