size of material should be slowed down. This will reduce or eliminate the amount of 9.5mm x 12.5mm aggregate being discharge from the overflow chute.
Asphalt Binder System -- Storage tanks are heated and insulated. Storage tanks are calibrated so the plant inspector can determine the quantity of asphalt binder being stored in each tank. Batch plants utilize a pump and a weigh pot to proportion the asphalt binder, a batch at a time. Continuous mix plants deliver the asphalt binder to the drum through an assortment of pump and meter combinations. The asphalt binder is delivered to the mixing chamber in a constant continuous flow.
Rubberized Asphalt Binder Storage – The components for rubberized asphalt binder,
allowed to tendency to
set in conventional asphalt storage tanks separate. Caltrans requires that storage tanks
ingredients would have a rubberized asphalt binder be
equipped with a heating system, temperature indicator, that will keep the binder in a homogeneous condition.
Hot Storage - 19 mm or 12.5 mm maximum sized aggregates that are mixed in batch type plants shall be stored, after being dried; 1) separated into three or more sizes, 2) and each size shall be stored in a separate bin. Storage bins must be equipped with chutes to prevent overflow into adjacent bins.
Proportioning - In simple terms, the amount of each material (aggregates and asphalt binder) that will be combined to produce asphalt concrete. One example might be, 25% of the 12.5 mm x 9.5 mm aggregate, 25% of the 9.5 mm x 4.75 mm aggregate and 50% of the 4.75 mm x 75- m aggregate. Note the combined aggregate portions total 100 percent. The asphalt binder percent is by dry weight of aggregate and is specified as a percentage. For example, 100 kg of aggregate and 6 kg of asphalt binder indicates an asphalt ratio of 6 percent.
Mass Flow, Coriolis Effect Asphalt Meter and Transmitter - Most continuous mixing AC plants use this type of asphalt meter. A mass flow meter will give the plant inspector a lot of useful information. A few of the features include, asphalt binder production rates (TPH, PPM, GPH, LPM, etc.), total amount of asphalt binder pumped through the meter using the resettable totalizer, specific gravity (pounds per gallon, etc.) of asphalt binder, temperature of the asphalt binder, and span number.
Volumetric Type of asphalt meter. controller by the
Asphalt Meter – Some continuous mixing AC plants still use this type
This meter is only as
as the specific gravity gravity is taken from
input into the the shipping
documents that should be taken controller. This
accompany each load of paving asphalt. Samples of paving asphalt on a daily basis to verify the specific gravity used by the asphalt meter type of asphalt meter must be equipped with a functioning temperature
correction factor (1.0000 @ 60°F) and the specific gravity to convert volume to mass.