CALIBRATION OF HOT MIX PLANT, CONSTRUCTION OF JOINT & LAYING OF TEST TRACKS

PLANT GENERAL

Plant can be batch or continuous plant.- Mixing time required for mixing depend on the design of paddles and the speed of rotation.

LARGE FIXED CENTRAL PLAN:- This preferably batch type with large aggregate storage bin- It may serve a large nos of customers in a fairly wide area, Site plant which may be located at source, which may be mobil on semi mobil set up for particular Job.

BATCH PLANTS:- The various sizes of aggregate excluding mineral filler, are fed into the automatic cold feed hoppers, in approximate correct volume prop, Aggregate then pass through the drying drum and heated to correct mixing temperature. From drum the aggregate passes by means of enclosed elevator to screens where it is separated into two or more sizes according to number of Bins are kept clean and checked at regular interval for damage, specially bitumen bin is to be washed everyday at the end of the work. Mineral filler is fed separately and lifted and store separate storage bin, weighing of material is done manually or in modern plant in automatically. Time require for mixing with depend on the design of paddles and speed of rotation. CONTINUOUS PLANT:- In this case also, aggregate after drying- lifted to bins through screen, but in this case from storage bin, however the aggregate passes through continuous stream through adjustable feed gate, which correctly proportion the various sized aggregate to be mixing chamber. Here the bitumen is added in a continuous spray, the amount being controlled by adjusting the rate of output of the metering pump. In the mixing chamber the various component of mix are agitated and mix by paddles which passes mix through mixing chamber to discharge hopper by which time are the aggregate particles will be completely coated. At the discharge end of the mixing chamber a mechanical device is fitted by means of which it is possible to vary the mixing time from mixing chamber the mix is discharge into lorries for transportation to the site of work.

PLANT CAPACITY60 M.T.B.N.130%240%320% f10% B 6 P.C.Total output per minute for mixture= 60 X 1000 = 1000 kg60Normal operating speed 15 r.p.m output 1000 = 66.66 kg per r.p.m15wt of bitumen = 66.66 X .06 = 3.9906 = 4 kgamount of filler & aggregate 66.66 4 = 62.66 kg B.N. 1- 62.66 X .30 -18.798 kg 2-62.66 X .40 -25.064 62.66 X .20 -12.532 62.66 X .10 - 6.260