Hot Mix Asphalt Production

Road Pavement Forum: 10th April 2006 Chris Lange PMP, Pr.Tech.(Eng) Director (Technical) Much Asphalt (Pty) Ltd         Plant types and basic components Plant calibration Dust extraction Filler handling and control Aggregate heating Procurement / handling of raw materials Finished product storage Delivery Exhaust Fan Filter Baghouse Primary dust collector Hot Storage Bins HMA made continuously and sent to storage silos Bitumen Tanks Scalping screen to remove oversize aggregate Belt scale Drying and mixing drum Cold Feed Bins TWIN DRUM PLANT : COUNTER-FLOW RAP Feed Plant filler storage and feed Filter Baghouse Finished product storage Coating & mixing drum Aggregate feed Drying & heating Drum Parallel-Flow Drummixer Zones Air Combustion Heating Drying Mixing BIT Hot Mix Asphalt Counter-Flow Drummixer Zones Air Mixing Combustion Heating Hot Mix Asphalt Bitumen Drying Aggregate Counter-Flow Batch Plant Dryer Zones Combustion Heating Drying Air Aggregate Hot Aggregate Batch Plant Elements Primary Filter Baghouse collector Batch/Mixing tower Hot Storage silos Bitumen storage tanks r e y Dr um Dr Cold feed bins RAP Feed Plant Automation – Operating System Graphics Binder Content Voids in Mix Filler Content Plant Mixing Tower Skip Bucket Winch The End [...]... Valve Air Gas flow Optional knock down plate Bitumen Fines mix with hot mix asphalt Exhaust fan Exhaust fan Manifold Dust screw Manifold Dust screw Automatic Damper Controls Hot Elevator Cyclone feeding fines directly back Batch tower   Remove particulate matter – Primary – Secondary Return fines to the mix – Affects void content – Affects mix stiffness – Difficult to control ...Aggregate to screens Screens size aggregate Hot aggregate travels up bucket elevator Aggregate weigh hopper Pugmill Aggregate from dryer Bitumen weigh pot Hot mix asphalt dispensed into truck / hot- bin Aggregate and bitumen weigh hoppers Bitumen Weighhopper Warren Brothers Patent Application Drawing: Original Batch Plant