DRUM PLANTS

The solid binder material shall be accurately metered into the mixing portion of the drum within one foot of the asphalt oil injection point or into the after-mixer with an approved proportioning apparatus suitable of ICC certification for custody transfer of materials. (i.e.; belt scale, metering auger, or similar).

The solid binder shall be added to heated aggregate which shall provide a minimum mix temperature of 265 ° Fahrenheit. The maximum mix temperature shall not exceed 290 ° Fahrenheit at the discharge point of the drum. Mix above or below these temperatures shall be rejected.

* The above mentioned addition point shall also include RAP collars if they are "newer generation" collars which do not have direct flame contact with the RAP and/or solid binder.  (i.e.; CMI or Astec double drum or similar). This method shall utilize the above mentioned metering devices and at no time will the solid binder be directly exposed to open flame. An appropriate H2S audible detector shall be installed within two feet of the discharge of all plants being used and be capable of registering a min. of 10 ppm. At no time shall the reading exceed the amount required in accordance with O.S.H.A. standards.

BATCH PLANTS

The solid binder material shall be accurately metered into the mixing portion of the pug mill during the period of the batching process where the addition of the asphalt oil normally occurs. This can be accomplished on a weight basis by a certified scale or with an approved volumetric device that has an approved proportioning apparatus suitable of ICC certification for custody transfer of materials.  The minimum mix time shall be 20 seconds with 30 seconds preferred. The solid binder shall be added to heated aggregate which shall provide a minimum mix temperature of 265 ° Fahrenheit. The maximum mix temperature shall not exceed 290 ° Fahrenheit at the discharge point of the plant. An appropriate H2S audible detector (such as a Dreager or other) shall be installed within two feet above the discharge of the plant and be capable of registering a min. of 0.5 ppm. At no time shall the reading from this unit exceed 50 ppm or the amount required in accordance with O.S.H.A. standards.

* IMPORTANT NOTE;