Asphalt Plant Road Construction

Hot Mix Asphalt – Temperature Control

Temperature  control of  hot mix asphalt concrete  is  required  in  all  plants  except those  producing  cold  mixes  using bitumen  emulsion.  Thermometers  (mercury  or  electric)  has to be  located  in  the  flow  of aggregate  from  the  dryer,  in  each  hot  bin,  and  in  the  binder  supply  line.  The  number  of thermometers used and their locations have to be such that the readings are valid indications of the  material  temperatures.  The  thermometers  should  have accurate  to  within  I  percent  and  their registrations clearly and conveniently visible to the operator.

In the production of Hot mixes the aggregate must be heated only sufficiently to obtain a mix at the required temperature. Overheating may result in damage by oxidation of the binder while it is in the form of thin films during the mixing process.

If the mix is too hot, the binder will drain from the particles of aggregate with the result that  some  portions  of  the  mix  may  be  dry  and  others  fatty.  This  applies  particularly  to  open graded mixes. See related posts of hot mix asphalt concrete for further knowledge.