Both make the same product, hot mix asphalt. They differ in how they proportion the ingredients and where the mixing happens.
| Batch plant | Drum mix plant | |
|---|---|---|
| How it produces | One batch at a time, usually 2 to 6 tons every 45 to 60 seconds | Continuously, typically 200 to 600+ tons per hour |
| Gradation control | Hot aggregate is re-screened into hot bins, then weighed bin by bin | Cold feed bins are calibrated; a belt scale weighs the blend on the way to the drum |
| Asphalt binder | Weighed in a bucket for each batch | Pumped and metered at a rate locked to the belt scale |
| Where it mixes | A separate twin-shaft pugmill | Inside the drum, in a mixing zone behind the burner flame |
| Changing mixes | Easy, can change from one batch to the next | Works best on long runs; changeovers create some waste |
| Recycled asphalt (RAP) | Usually about 10 to 30% | Commonly 20 to 40%, and higher on some plants |
| Loading trucks | Often straight from the pugmill (silos are optional) | From storage silos fed by a slat conveyor |
| Moving parts | More: hot elevator, screens, hot-bin gates, weigh hoppers, pugmill | Fewer, which usually means simpler upkeep |
| Best fit | Many different mixes and smaller orders | High-volume paving with steady demand; most new U.S. plants |