Asphalt plant technology offers end-of-day shutdown options that help prepare you for the most productive start-up the following day.
Empty mix from silos
Let’s say the governing authority doesn’t allow leaving a specialised mix in a silo because it will age overnight. Or perhaps the owner of your facility doesn’t want to pay the added cost of keeping silos heated overnight. This means the plant operator must ensure silos are completely empty before powering down.
To start this procedure, the plant operator will plan and communicate with the foreman on the paving job in an effort to synchronise the end of asphalt mix production with the end of the day’s paving. If there’s still mix in the silo, the plant operator will direct ground personnel to position a haul truck under the silo so a team can empty the last load (or two) and stock it at the RAP pile.
Store mix overnight
Long production runs offer continuity in mix quality. This also provides the option to fill the silos and leave mix overnight. Thanks to today’s long-term storage capabilities, the plant operator can ensure truck traffic flows more smoothly in the morning by filling a silo (or two) with commercial mix before clocking out at night. That mix can be used to feed the next day’s early morning lineup.
Before shutting down, the plant operator will use software controls to ensure he has filled the correct silo(s) with the correct mix design(s) for the next day’s needs. While that sounds simplistic, it matters greatly to the customers who expect a specific mix so be sure to double-check it.
Then, the operator will check the temperatures of silos and silo gates to ensure the heat is working correctly and the temperature levels are appropriate for an overnight stay. This will add some cost to the utility bill, but it is vital to keep material from solidifying overnight.
The mix can be 10ºC colder than normal, as the stack effect will heat the material. The opening and discharge gates must be closed and sealed. Otherwise, the stack effect will be higher and the bitumen will be burned by morning.
Be careful that overnight moisture doesn’t impact the materials. Don’t stock the materials for too long in the loadout bin, and be sure to take preventive steps such as using dedicated long-term storage silos.
Following the shutdown procedures at the end of the day will help streamline plant start-up the next morning.