4. Mix Production

4.11 Troubleshooting and Checklists

A daily summary report of all plant activities should be kept. This should include the results of all tests performed during the day and a tabulation of the amounts of material received and used during production.

The following checklists can be used as needed by plant operation and QC personnel to determine plant readiness for production:

PLANT CHECKLISTS

Checklist for material handling and storage

❑       Do the aggregates meet specifications?

❑       Are the proper sizes being produced?

❑       Is the aggregate storage satisfactory?

❑       Are the stockpiles separated properly?

❑       Are the stockpiles constructed properly?

❑       Is the stockpiled aggregate handled correctly?

❑       Is segregation being controlled?

❑       Is the mineral filler or hydrated lime being kept dry?

Checklist for cold feed

❑       Does the cold-feed setup comply with specifications?

❑       Do the cold-feed bins contain properly sized aggregates?

❑       Are the cold-feed bins charged properly?

❑       Are the cold-feed bins flowing (without bridging) properly?

❑       Do the cold aggregate feeders perform satisfactorily?

❑       Are the cold aggregate feeder gates set correctly?

❑       Are all cold aggregates being fed uniformly?

❑       Are the cold aggregate feeders calibrated?

Checklist for asphalt heating, circulating, and temperature of mixture

❑       Is the asphalt uniformly heated to the temperature specified?

❑       Have all the lines been checked for leaks?

❑       Are mix production temperatures within specifications?

❑       Has the binder feed been calibrated?

Checklist for drum-mix plant

❑       Have the aggregate feeds been calibrated?

❑       Has the liquid binder feed been calibrated?

❑       Are the aggregate and binder feeds interlocked?

❑       Are the plant components in good condition and adjusted?

❑       Is the binder at the proper temperature when introduced into the drum?

❑       Does the mix appear to be uniformly coated?

❑       Is water dripping from the bottom of the storage silo?

❑       Do the scales comply with specifications?

❑       Have the scales been calibrated?

❑       Have the scales been checked for tolerance?

Checklist for batch plant

❑       Do the scales comply with specifications?

❑       Have the scales been calibrated?

❑       Have the scales been checked for tolerance?

❑       Does the binder bucket tare properly?

❑       Does the weigh box hang free?

❑       Are the mixer parts in good condition and adjustment?

❑       Is the proper size batch being mixed?

❑       Are the bin draws in proper sequence?

❑       Is binder distributed uniformly along the length and width of the pugmill?

❑       Are the aggregates and binder at proper temperatures?

❑       Do any valves or gates leak?

❑       Is the mixing time adequate?

❑       Are the weight points set properly for batch weights?

❑       Are the mixer shafts revolving at proper speed?

❑       Are the screen capacities sufficient to handle the feed from the dryer?

❑       Are the screens clean?

❑       Are the screens worn or broken?

❑       Is the screen carryover irregular or excessive?

❑       Are the hot-bin partitions solid without signs of excessive wear?

❑       Are the overflow chutes free-flowing?

❑       Is the amount of needed material in each bin being maintained?

❑       Is the access for sampling adequate?

Checklist for dryer and dust collector

❑       Does the dryer and dust collector comply with specifications?

❑       Is the aggregate properly dried?

❑       Are the aggregates at the proper temperature?

❑       Are the dryer components in balance?

❑       Is the dryer production in balance with other plant components?

❑       Are temperature-measuring devices installed correctly and calibrated?

❑       Are the collected fines wasted, or are they fed back to the mixing chamber?

❑       Is the dust-return system in balance with the dryer?

Checklist for storage silos

❑       Does the silo contain a batcher?

❑       Are the baffles or other devices to prevent segregation working properly?

❑       Is the silo discharge opening properly configured to prevent segregation?

❑       Does the discharge gate open and close efficiently?

Checklist for sampling and testing

❑       Are sufficient samples being taken to comply with the sampling plan?

❑       Are the samples representative of the material?

❑       Are all the tests being conducted properly?

❑       Are the test results available soon enough to be effective?

❑       Are the records complete and up-to-date?

Checklist for miscellaneous responsibilities

❑       Have the truck beds been inspected?

❑       Are the truck beds drained after release agent application?

❑       Is the release agent on the agency’s Approved Product List (APL)?

❑       Do the trucks meet specification requirements?

❑       Are the trucks equipped with tarpaulins or covers?

❑       Does the mix have a uniform appearance?

❑       Does the mix satisfy the placing requirements?

❑       Have all personnel been properly instructed?

❑       Are safety measures being observed?