An inner drum for use in a dryer/mixer in connection with the production of an aggregate-binder mix includes a plurality of mixing paddles disposed on the outer surface of the inner drum and arranged in a plurality of rows. The mixing paddles are configured to rotate through a mixing chamber as the inner drum rotates within an outer drum of the dryer/mixer to mix aggregate and binder together. Interstitial spaces are formed between rows of mixing paddles and material leads, where aggregate material preferentially travels as the inner drum is rotated, extend along the mixing chamber. At least one interstitial mixing paddle is located on the outer surface of the inner drum and in one of the interstitial spaces at one of the material leads. The interstitial mixing paddle rotates through the mixing chamber as the inner drum rotates to also mix the aggregate and binder together.

A system for producing hot mix asphalt includes a generator having an exhaust port; a dryer drum having an inlet; a duct connecting the exhaust port to the inlet, the duct conveying a first flow of hot gas from the exhaust port; an exhaust bypass vent conveying a second flow of hot gas diverging from the first flow of hot gas; and a valve disposed at a junction between the duct and the exhaust bypass vent for adjusting a flow rate of the second flow of hot gas. The dryer drum produces hot mix asphalt from asphalt materials using a third flow of hot gas diverging from the first flow of hot gas and entering the dryer drum through the inlet.

An inner drum for use in a dryer/mixer in connection with the production of an aggregate-binder mix includes a plurality of mixing paddles disposed on the outer surface of the inner drum and arranged in a plurality of rows. The mixing paddles are configured to rotate through a mixing chamber as the inner drum rotates within an outer drum of the dryer/mixer to mix aggregate and binder together. Interstitial spaces are formed between rows of mixing paddles and material leads, where aggregate material preferentially travels as the inner drum is rotated, extend along the mixing chamber. At least one interstitial mixing paddle is located on the outer surface of the inner drum and in one of the interstitial spaces at one of the material leads. The interstitial mixing paddle rotates through the mixing chamber as the inner drum rotates to also mix the aggregate and binder together.

An improved geometry for flights used in rotary drums of aggregate dryers in the manufacture of asphalt causes the aggregate to shower in an even veil across the full width of the drum under all loading conditions. An opening in the flight having a narrow bottom and wider top allows more aggregate to shower early, especially when flights are lightly loaded, on the uplift side of the drum to complete the aggregate veil and prevent hot gases from bypassing. The opening is oriented with its narrow bottom nearest the inner surface of the drum and its wider top farthest therefrom. The opening does not extend through the full height of the flight, which would form an undesired gap allowing an excessive volume of aggregate to flood out of fully loaded flights on the uplift side of rotation. Such flooding discharge causes a similar imbalance of drying to that caused by too little discharge from light loaded flights. The size and shape of the opening can be varied to adjust the amount of aggregate discharged from each flight to form the veil and to adjust the shape of the veil.

A device for manufacturing hot-mix coated materials includes an oven (1) having an enclosure (2) provided towards its two opposite ends with a main inlet (3) designed to receive granular materials and with a main outlet; and a heater (10) defining a combustion section (5) inside the enclosure (2). The enclosure (2) starting with the combustion section (5) and continuing with a drying section (6), and then with a mixing section (7). The device is further provided with a bypass outlet (11) and with an external mixer (12) that is connected to the bypass outlet (11), which outlet is fitted with a blocking system (15) allowing granular materials to pass towards the inlet (13) of the external mixer (12) and a closed position allowing granular materials to pass towards the mixing section (7).

An asphalt processing system is formed from a heating drum and an induction heating system. Flights move asphalt through the heating drum, which concurrently heat the asphalt along with the heating drum wall. A mixing drum can be connected to the heating drum, and include paddles or flights to move the asphalt, while concurrently mixing the material to ensure consistent temperatures through the asphalt cement. The asphalt is heating using one or more induction heating systems to quickly heat the asphalt to between 275 F. and 750 F., followed by moving the asphalt to between 275 F. and 350 F. The system can include a convection system that heats recirculated air through the heating drum. A water condenser can be employed to remove moisture during air recirculation, and reduce asphalt moisture content. The asphalt cement is optionally modified by addition of one or more rejuvenation oils. This system is particularly useful for recycled asphalt pavement, but can be used for all asphalt products.

An asphalt processing system is formed from a heating drum and an induction heating system. Flights move asphalt through the heating drum, which concurrently heat the asphalt along with the heating drum wall. A mixing drum can be connected to the heating drum, and include paddles or flights to move the asphalt, while concurrently mixing the material to ensure consistent temperatures through the asphalt cement. The asphalt is heating using one or more induction heating systems to quickly heat the asphalt to between 275 F. and 750 F., followed by moving the asphalt to between 275 F. and 350 F. The system can include a convection system that heats recirculated air through the heating drum. A water condenser can be employed to remove moisture during air recirculation, and reduce asphalt moisture content. The asphalt cement is optionally modified by addition of one or more rejuvenation oils. This system is particularly useful for recycled asphalt pavement, but can be used for all asphalt products.

A system and process for detecting dynamic segregation in concrete rotated within a mixer drum, such as mounted on a delivery truck. A system processor is programmed to monitor an instantaneous and averaged rheology parameter and to deploy protocols for detecting segregation. A first protocol comprises monitoring the averaged slump during and immediately after a jump in drum speed of at least plus or minus four rotations per minute and detecting when a change in the averaged slump value meets or exceeds a threshold; and a second protocol comprises monitoring the instantaneous slump when the mixer drum is rotating at a constant speed for at least three successive rotations and detecting when the instantaneous slump value meets or exceeds a threshold limit. Once segregation is detected, one or more operations can be initiated, such as initiating an alarm or adjusting the mix.

A system for metering reinforcing aramid fibers into an asphalt mixer includes a vertical feed chute with straight walls that spans substantially a full diameter and a full length of a horizontal feed auger to feed bulk fibrous material by gravity from the feed chute in a radial direction along the length of the feed auger. The feed auger is rotated at a controlled rate proportionally to the rate of production of an asphalt and mineral aggregate mixture. A pneumatic conveying line conveys the reinforcing fibers from an outlet end of the feed auger to an asphalt mixer for mixing with the asphalt and mineral aggregate to produce a fiber reinforced asphalt concrete with an accurately proportioned amount of fiber dispersed therein.

A system and process for detecting dynamic segregation in concrete rotated within a mixer drum, such as mounted on a delivery truck. A system processor is programmed to monitor an instantaneous and averaged rheology parameter (e.g., instantaneous and averaged slump values) and to deploy one or more protocols for detecting the occurrence of segregation. A first protocol comprises monitoring the averaged slump or other rheology value of concrete during and immediately after a jump in drum speed of at least plus or minus four rotations per minute and detecting when a change in the averaged slump value meets or exceeds a threshold limit pre-selected by the user or the system processor; and an optional second protocol comprises monitoring the instantaneous slump or other rheology value of the concrete when the mixer drum is rotating at a constant speed for at least three (and more preferably for at least five) successive rotations and detecting when the instantaneous slump value meets or exceeds a threshold limit pre-selected by the user or processor. Preferably, both protocols are used, in any sequence, to confirm segregation within the rotating drum. Once segregation is detected, one or more operations can be initiated, such as sending an alarm or signal to the operator to confirm dynamic segregation is detected, introducing an admixture to mitigate the segregation, sending data to the batch plant for adjusting the mix design for subsequent deliveries, or other operations.