SECTION 401
3.6 Mixing Temperature.
3.6.1 Method Requirements.
3.6.1.1. The Engineer may adjust the job mix formula temperature within the limits of 260° and 350°F according to the
existing conditions. Material with a temperature at discharge outside the job mix formula tolerance may be rejected. In no case
will a mixture be accepted with a discharge temperature in excess of 375°F.
3.6.1.2 During hot weather, the temperature of the mixture when discharged shall be as low as is consistent with proper
mixing and placing. During cold weather, a temperature approaching the upper limit is desirable
3.6.2 Performance Requirements (QC/QA).
3.6.2.1 The job mix formula temperature may be adjusted within the limits of 260 °F and 350 °F according to the existing
conditions. Material with a temperature at discharge outside the job mix formula tolerance may be rejected. In no case will a
mixture be accepted with a discharge temperature in excess of 375 °F.
3.7 Hot Storage System — General.
3.7.1. Material may be placed in a storage silo for a period not to exceed 24 hours from the time of mixing. The upper and
lower gates when closed shall create an airtight seal. The silo shall be filled to capacity. 24 hour storage will not be allowed if
there is reason to believe there is a problem with the gate seals or excessive heat loss.
3.7.2 The hot storage system shall be capable of conveying the hot mix from the plant to insulated and enclosed storage
bins and storing the hot mix without appreciable loss in temperature, asphalt migration, segregation, or oxidation.
3.7.3. The conveyer system may be a continuous type or skip bucket type. If the continuous type is used, it shall be enclosed
to prevent a drop in mix temperature. Ifthe skip bucket type is used, the bucket must be of sufficient capacity to transport an
entire batch and mass dump it into the bins.
3.7.4 The storage bins shall be designed in such a manner as to prevent segregation of the hot mix during discharge from
the conveyor into the bins and shall be equipped with discharge gates that do not cause segregation of the hot mix while loading
the mix into the trucks. The storage bin heating system shall be capable of maintaining the mix temperature without localized
heating (hot spots).
3.7.5 The bin shall be equipped with a light or indicator to show when the level of material reaches the top of the discharge
cone. The bin shall not be emptied below the top of the discharge cone until the use of the bin is completed each day. The
material remaining in the discharge cone may be rejected if there is evidence of segregation.
3.8 Weighing and Hauling — General.
3.8.1 The Contractor shall provide an approved automatic printer system that prints the weights of the material delivered,
provided the system is used in conjunction with an approved automatic batching and mixing control system. Such weights shall
be evidenced by a weight slip for each load.
3.8.2 Weight slips shall include requirements as shown in 109.01 and the following for batch plants with automatic
proportioning equipment:
(a) Tare weight of aggregate weigh box.
(b) Tare weight of asphalt binder weigh bucket.
(c) Accumulative weights as batched for cach aggregate (total of last aggregate will be aggregate total).
(d) Weight of asphalt binder.
(e) Accumulated total weight of batch.
3.8.3 Each weight slip will show a consecutive load number and shall include an accumulative total of material delivered
for each day.
3.9 Vehicles — General.
3.9.1 The inside surfaces of vehicles may be lightly lubricated with a soap solution or non-petroleum release agent that
will not be detrimental to the mix. Equipment that leaks oil, diesel fuel, gasoline, or any other substance detrimental to the
pavement will not be allowed on the project.
3.9.2. The mixture shall be transported from the paving plant to the project in trucks having tight, smooth, metal beds
previously cleaned of all foreign materials. Truck beds may be lined with a polyethylene type material designed and installed
for hauling hot bituminous mixes. Each load shall be covered with canvas or other suitable material of sufficient size and
2016 NHDOT
Go To= TOC Division 190 Division 200 Division 300 Division 400 Standard
Division 500 = Division 600 Division 700 Specifications
