A batch plant’s output is simply batch size × batches per hour. A twin-shaft mixer that takes 1,500 kg and completes a cycle every 45 seconds — 80 cycles an hour — produces 120 t/h. Change either number and the output changes.

What happens in one cycle

Phase What happens Typical share of the cycle
Weighing Aggregate, filler and bitumen are weighed in their hoppers — overlapping with the previous mix Overlaps
Aggregate and filler discharge Hot aggregate and filler drop into the mixer A few seconds
Dry mixing Aggregate and filler blend before the binder Several seconds
Bitumen injection Bitumen is sprayed into the mixer A few seconds
Wet mixing Binder coats every particle The longest phase
Discharge Mixer gates open into the truck or silo skip A few seconds

Because the next batch is weighed while the current one mixes, the cycle is set mainly by discharge + dry mix + wet mix + discharge.

Output by mixer size and cycle time

Mixer (kg/batch) 45 s cycle (80/h) 50 s cycle (72/h) 60 s cycle (60/h)
750 60 t/h 54 t/h 45 t/h
1,000 80 t/h 72 t/h 60 t/h
1,500 120 t/h 108 t/h 90 t/h
2,000 160 t/h 144 t/h 120 t/h
3,000 240 t/h 216 t/h 180 t/h
4,000 320 t/h 288 t/h 240 t/h

These match the mixer sizes in our stationary batch plant series: the RMX-B120 has a 1,500 kg mixer, the RMX-B160 a 2,000 kg mixer, and so on.

Mixes that need longer cycles

Mix Why it takes longer
Stone mastic asphalt (SMA) with fibers Fibers must be dispersed evenly
Polymer-modified binders Higher viscosity; coating takes longer
High RAP content RAP must blend and transfer heat with new aggregate
Fine or high-binder mixes More surface area to coat

When you plan a contract with these mixes, calculate output with the longer cycle — or choose a larger mixer.

The mixer can only mix what the plant supplies:

  • Drying drum and burner must dry and heat enough aggregate per hour at your moisture — see rated vs real output
  • Hot elevator and screen must carry and split that flow
  • Hot bins must hold enough of each size between batches
  • Trucks or silo must take each batch as it is discharged

A balanced plant has every link sized for the same output — compare all of them when you compare quotes.

Questions to ask your supplier

  1. What mixer size and standard cycle time give the rated output?
  2. What is the minimum cycle time with my mix and specification?
  3. Can the drum supply the rated output at my wet-season moisture?
  4. Is there room for a fiber feeder or additive dosing if I need SMA or modified mixes?

Ask us to check the cycle time for your mixes.