Abstract:
A high-speed turbine mixer combines water and cement into a pre-mixed cement paste that is added to aggregates to create a concrete mix. The turbine mixer includes a housing that cooperates with an auger to move dry cement into a mixing chamber where water is added. A mixing plate rotates at high speed to break up water and cement into small particles that enhances the hydration of the cement and increases the air content in the resultant cement paste. The cement paste is then conveyed to a mixing auger to be combined with aggregates to create a concrete mix. The mixing plate divides the mixing chamber to force the mixing water and cement particles to pass through a circumferential annular opening past agitating fins. Admixtures can be added to the cement as a powder or to the water as a liquid for incorporation into the cement paste.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is a division of U.S. patent application Ser. No. 10/786,183, filed Feb. 25, 2004, now U.S. Pat. No. 7,281,839, granted Oct. 16, 2007, and claims domestic priority of U.S. Provisional Patent Application Ser. No. 60/450,570, filed Feb. 28, 2003, the contents of which are incorporated herein by reference. 

   BACKGROUND OF THE INVENTION 
   The present invention relates generally to an apparatus to mix concrete and, more particularly, to a turbine cement/water mixing apparatus for premixing a cement slurry for use in the production of concrete. 
   Concrete trucks, such as is described in U.S. Pat. No. 3,310,293, issued to Harold M. Zimmerman on Mar. 21, 1967, and U.S. Pat. No. 4,406,548, issued to Paul M. Haws on Sep. 27, 1983, carry supplies, such as aggregate, cement and water, in discrete hoppers from which the supplies are drawn in predetermined ratios to be deposited in a mixing auger apparatus where the combined supplies are mixed and turned into concrete to be discharged from the mixing auger externally of the concrete truck. This mixing auger apparatus is formed from a generally semi-circular flexible housing against which a standard pitch, spiral flighted auger works to not only mix the combined supplies, but to convey the combined supplies, and ultimately the created concrete, to the remote discharge end of the auger. 
   Conventional ready-mix concrete production has utilized a rotatable drum mounted on a truck frame to deliver mixed concrete to a delivery site by discharging the mixed concrete from the elevated, rearwardly directed, central discharge opening of the drum. More recent variations of the conventional concrete mixers have reoriented the drum to position the discharge opening toward the front of the truck, which enables the operator to control the discharge and delivery of the mixed concrete through a front-mounted discharge chute mechanism without leaving the cab of the truck. 
   Concrete trucks, as described in the aforementioned U.S. Pat. Nos. 3,310,293 and 4,406,548, located the mixing auger apparatus at the rear of the truck to receive the respective supplies fed downwardly and rearwardly thereto. The upward incline of the mixing auger allowed the mixed concrete to be discharged from a slightly elevated position to be delivered through a cooperative discharge chute mechanism. A mere repositioning of the mixing auger apparatus to the front of the truck to enable the forward discharge of the mixed concrete forwardly thereof is not a simple design choice as the operator&#39;s cab of the truck prevents the relocation of the mixing auger apparatus to the opposing front position. The forwardly delivering concrete truck must be capable of delivering mixed concrete at a forward position above the cab of the truck so that a discharge chute mechanism, which must be storable in a transport position above the truck cab out of the line of sight of the operator, can deliver the mixed concrete to the ground forwardly of the truck. 
   The mobile concrete production system includes a storage tank mounted on the chassis bed which has two longitudinally extending hoppers separated by a common wall. One hopper contains sand, and the other contains gravel or stone. A central, longitudinal conveyor operatively mounted along a bottom trough common to both hoppers receives sand and stone and delivers the materials to a rear discharge end. Also, the system includes a separate cement hopper as well as a separate water tank mounted on the chassis. Cement is dispensed in the desired proportion by a metering mechanism from the cement storage hopper into the discharging sand and stone and all three ingredients are then delivered into a elongated mixing trough mounted on the rear of the chassis. Water is added with the materials at the entrance and the ingredients are mixed into concrete in the trough before being discharged from the trough at the job site. 
   Many advantages and benefits are enjoyed by persons who employ the mobile concrete system in their concrete production business. An important one is that the system permits the formulation and delivery of relatively continuous amounts of concrete which can be used to fulfill orders where only small quantities of concrete are needed, thus obviating the need for taking such quantities from a single large pre-mixed batch. Since only a small portion of the system, the mixing trough, is utilized for mixing the concrete, it can be quickly and easily cleaned after completion of a “mixing” or production operation. Equally important, since the mixing of the concrete is performed “on site”, selective variation of the ingredients of the mixture can be readily accomplished and the water content of the mixed concrete can be easily controlled. Finally, in the mixing trough, a positive mechanical mixing action at a desired rate is performed to assure a uniform dispersal of all the ingredients of the concrete mix. 
   The incorporation of cement into a concrete production system, whether a ready-mix batch system or a mobile system, typically involves the mixing of dry cement with the aggregate and water until the mixture is homogenous. Admixtures are often added to the mixture to accomplish desired functions, such as changing the set time, increasing temperature, adding color to the concrete mixture, incorporating air into the mixture, etc. In both batch and mobile concrete production systems, a certain percentage of individual cement particles remain unhydrated despite an aggressive mixing action and despite the incorporation of additives to improve the hydration of the cement. A more thorough hydration of the individual cement particles can lead to increase strength and reduce concrete set times. 
   Some concretes produced by the mobile production system encounters a phenomenon commonly referred to as “false set”, which can be described to as a premature stiffening of the concrete. This phenomenon is typically solved through the use of a specially formulated cement product that is more expensive than the cement used in batch production systems. Accordingly, the unit cost of mobile production concrete is higher than conventional batch production concrete. It would be desirable to provide a process that would improve the mobile production of concrete to permit the use of a conventional cement formulation without incurring the false set problems. 
   The production of concrete, whether via a mobile concrete system or a ready mix system, typically involves the placement of dry cement, dry aggregate and dry sand into a mixing apparatus where water is added to hydrate the cement and create concrete. Admixtures to entrain air, to increase strength, to increase hydration, to die the concrete, etc. are added to the mixture during the mixing operation. Full hydration of the cement is such operations is not possible, thus chemical additives for the produced concrete is normal. 
   It would, therefore, be desirable to provide an apparatus and an improved process for producing concrete by effecting a substantially complete hydration of the cement particles. 
   SUMMARY OF THE INVENTION 
   It is an object of this invention to overcome the disadvantages of the prior art by providing a turbine mixer to pre-mix water and cement before delivery to the mixing auger of a mobile concrete production machine. 
   It is another object of this invention to improve the hydration of cement particles in the production of concrete. 
   It is an advantage of this invention that the improved hydration of cement particles increases the compressive strength of concrete. 
   It is a feature of this invention that a high speed, rotating turbine blade breaks up cement and water particles into small sizes for improved mixing and hydration of the cement particles. 
   It is another advantage of this invention that the pre-mixing of water and cement with a high speed turbine mixing apparatus reduces bleed water in concrete. 
   It is another feature of this invention that the mixing action induced by the high speed turbine mixer increases air content in the resultant cement paste. 
   It is still another advantage of this invention that the increased air content in the resultant cement paste will reduce and possibly eliminate the need for air entrainment admixtures normally added to concrete mixes. 
   It is yet another advantage of this invention that the improved mixing action to create a pre-mixed cement paste from water and cement before being added to aggregates may eliminate false sets in concrete. 
   It is still another feature of this invention that the turbine mixing apparatus permits a more efficient addition of admixtures by permitting the incorporation of the admixture, whether powder or liquid, into the mixing process in the turbine mixer. 
   It is still another object of this invention to provide a method of producing concrete that will provide a higher quality concrete product. 
   It is yet another feature of this invention that the method of producing concrete includes the pre-mixing of water and cement by a high-speed turbine mixer to create a cement paste before being added to aggregates to create a concrete mix. 
   It is a further advantage of this invention that the pre-mixing of cement and water before being added to aggregates will eliminate the dispersion of cement dust into the atmosphere. 
   It is still a further advantage of this invention that the increased air content incorporated into the pre-mixed water and cement by the high-speed turbine mixer enhances the ability of the resultant concrete mix to be pumped and placed on site. 
   It is yet another object of this invention to provide a method of creating a more homogeneous and fluid concrete mix through the high speed pre-mixing of water and cement before being added to aggregates. 
   It is a further object of this invention to provide a turbine mixer for the pre-mixing of water and cement that is durable in construction, inexpensive of manufacture, carefree of maintenance, facile in assemblage, and simple and effective in use. 
   It is still a further object of this invention to provide an improved method of making concrete that provides a higher quality finished concrete product that can be incorporated into any type of configuration of concrete mixer or mixing apparatus. 
   These and other objects, features and advantages are accomplished according to the instant invention by providing a high-speed turbine mixer that combines water and cement into a pre-mixed cement paste that is added to aggregates to create a concrete mix. The turbine mixer includes a housing that cooperates with an auger to move dry cement into a mixing chamber where water is added. A mixing plate rotates at high speed to break up water and cement into small particles that enhances the hydration of the cement and increases the air content in the resultant cement paste. The cement paste is then conveyed to a mixing auger to be combined with aggregates to create a concrete mix. The mixing plate divides the mixing chamber to force the mixing water and cement particles to pass through a circumferential annular opening past agitating fins. Admixtures can be added to the cement as a powder or to the water as a liquid for incorporation into the cement paste. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The advantages of this invention will be apparent upon consideration of the following detailed disclosure of the invention, especially when taken in conjunction with the accompanying drawings wherein: 
       FIG. 1  is a schematic partial side elevational view of a representative mobile concrete production machine; 
       FIG. 2  is a schematic top plan view of the representative mobile concrete production machine shown in  FIG. 1  with portions broken away to depict the drag conveyors within the respective hoppers, the movement of the mixing auger being shown in phantom; 
       FIG. 3  is an enlarged schematic elevational view of the rear of the mobile concrete production machine shown in  FIG. 1  to depict the location of the turbine mixer incorporating the principles of the instant invention; 
       FIG. 4  is a top plan view of the turbine mixer incorporating the principles of the instant invention; 
       FIG. 5  is a right side elevational view of the turbine mixer depicted in  FIG. 4 ; 
       FIG. 6  is a bottom plan view of the turbine mixer depicted in  FIGS. 4 and 5 ; 
       FIG. 7  is an end view of the discharge end of the turbine mixer depicted in  FIGS. 4-6 ; 
       FIG. 8  is a left side elevational view of the turbine mixer depicted in  FIGS. 4-7 ; 
       FIG. 9  is a cross-sectional view of the turbine mixer corresponding to lines  9 - 9  of  FIG. 7 ; 
       FIG. 10  is an exploded perspective view of the turbine mixer shown in  FIGS. 4-9 ; 
       FIG. 11  is an elevational view of the rearward side of the mixing plate; and 
       FIG. 12  is an enlarged detail view of the adjustable discharge plate mounted on the cover of the turbine mixer. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring now to  FIGS. 1-3 , a representative mobile concrete mixer can best be seen. Left and right references are used as a matter of convenience and are determined by standing at the rear of the concrete mixer and facing the forward end, where the operator&#39;s cab is positioned, in the normal direction of travel. While the mobile concrete production system is shown and described in the drawings to explain the nature of the invention, one of ordinary skill in the art will readily understand that the principles of the instant invention are not limited to the mobile concrete production system and will be readily applicable to conventional ready mix, or batch operations as well. The turbine mixer shown in the drawings and described below will be applicable to any form of concrete production. Accordingly, a representative mobile concrete production system is shown in the drawings. 
   The mobile concrete production mixer  10  is provided with a chassis  12 , made mobile by tandemly arranged pairs of rear wheels  14  and a pair of front wheels (not shown). The chassis  12  has a bed  16  formed by longitudinally extending channels  18 , suitably interconnected by spaced transverse channels (not shown), and a cab  20  mounted at the forward end of the bed. A source of power, such as an engine (not shown) is suitably mounted on the chassis  12  at the front of the cab  20  for driving, preferably, the rear pairs of wheels  14 . 
   The representative concrete production system  10  includes a storage tank  22  mounted on the chassis bed  16  which has two longitudinally-extending hoppers  24 , 26  separated by a common wall  28  and having a common bottom trough  30 . One hopper  24  contains fine aggregates, such as sand, and the other hopper  26  contains coarse aggregates, such as gravel or stone. Mounted along the common bottom trough  30  of the hoppers is the aggregate conveying apparatus  32 . The conveying apparatus  32  receives sand and stone and delivers these materials to a rear discharge end  34  where a rearward cross-conveyor  43  receives the aggregates. Also, this representative concrete production system  10  includes a separate cement hopper  36  mounted transversely across the rear of the chassis bed  16  as well as a separate water tank  38  mounted on the bed  16  between the forward end of the storage tank  22  and rear side of the cab  20 . Cement is dispensed in the desired proportion from the hopper  36  by a metering apparatus  40  in the form of a drag conveyor  41 . In this representative prior art arrangement for a mobile concrete production system, the dispensed cement is delivered into the sand and stone aggregates being conveyed on a cross conveyor  43  by a delivery conveyor  37  receiving the dry cement from the metering mechanism  40  for delivery into an elongated mixing auger  42 . 
   The conventional mixing auger  42  mixes the ingredients into a concrete mixture after water is added thereto from the water tank  38 . Therefore, the concrete is mixed by the auger mechanism  44  at the job site just prior to being discharged from a terminal end  48  of a trough  45  of the mixing auger  42 . The mixing auger  42  can be mounted at a rear corner of the chassis bed  16  or at a central part of the chassis bed, depending on the arrangement of the components. The mixing auger  42  can be pivoted into a storage position out of the way during transport (shown in solid lines in  FIGS. 1 and 2 ) and a range of dispensing positions (shown in phantom in  FIG. 2 ) through a hydraulic mechanism  49 . 
   A batch, or ready-mix, concrete production system is accomplished in generally the same manner as that described above, except that the components of sand and stone aggregates, cement and water are weighed and combined in a large batch, whether pre-mixed at the batch plant or mixed in the delivery vehicle, instead of being metered into a mixing auger and discharged therefrom, as is described above with respect to the mobile concrete production system. Irrespective of the manner in which concrete is produced, the hydration of the cement particles is accomplished through the mixing action when combining the cement and water with the aggregates. 
   Referring now to  FIGS. 3-11 , the details of a turbine mixing apparatus  50  incorporating the principles of the instant invention can best be seen. The utilization of a turbine mixer  50  in the representative mobile concrete production system  10  revises the above description of the conventional mobile concrete production mixer  10  in that the metering mechanism  40  will not dispense cement onto the cross conveyor  43 , but instead directly into the turbine mixer  50 , as will be described in greater detail below. In the embodiment of the mobile concrete mixer  10  shown in  FIGS. 1-3 , the mixing auger  42  is positioned at the rear of the mixer  10  and is preferably of the flexible configuration described in greater detail in U.S. Pat. No. 5,486,047, issued on Jan. 23, 1996, to Harold M. Zimmerman, the description of which is incorporated herein by reference. 
   For batch or ready-mix concrete production operations, the turbine mixer  50  will be positioned to receive the dry cement from a hopper in a metered manner, instead of simply weighing a batch lot of cement for addition to the batch of concrete being mixed. Nevertheless, the operation of the turbine mixer  50  will be generally the same as that described below with respect to the representative mobile concrete production system  10 . 
   The turbine mixer  50  includes a housing  52  having a generally tubular portion  53  and a cylindrical mixing housing  54 , which could be cast to be integral with the tubular portion  53  or formed as assembled components as reflected in  FIG. 10 . The mixing housing  54  will have a larger diameter defined by the cylindrical shell  61 , than the tubular portion  53 . The tubular portion  53  has an inlet opening  53   a  in the top of the housing  52  positioned to be in flow communication with the metering mechanism  40 , which is in the form of a drag conveyor  41 , to receive the discharge of dry cement therefrom. The turbine mixer  50  also incorporates a mixing assembly  60  that includes an auger  63  mounted on a shaft  62  that is concentrically received within the tubular portion  53  and rotatably supported therein. The mixing assembly  60  further includes a mixing plate  65  affixed to the shaft  62  adjacent the terminus of the auger  63  to be rotatable therewith. 
   The housing  52  is formed in an elongated configuration with the inlet opening  53   a  at a forward portion in a manner that is open upwardly for receipt of the metered cement from the drag conveyor  41  into the tubular portion  53 . Immediately rearward of the inlet opening  53   a  is a panel  53   b  that has the same dimensions as the inlet opening  53   a . The housing  52  can be mounted on a slide carriage (not shown) that permits the fore-and-aft movement of the housing  52  relative to the metering mechanism  40 . Whenever the housing is positioned such that the inlet opening  53   a  is in flow communication with the metering mechanism  40 , the dry cement is conveyed into the turbine mixer  50 . 
   On the other hand, when the housing  52  is shifted so that the panel  53   b  is located where the inlet opening  53   a  would otherwise be positioned to receive dry cement, the panel  53   b  closes off the opening in the metering mechanism  40  so that the cement continues on its conventional path into the delivery conveyor  37  and into the mixing auger  42 , thus bypassing the turbine mixer  50 . Conversely, when the housing  52  is shifted to place the inlet opening  53   a  in flow communication with the conveyor  41 , the solid panel  53   b  closes off the opening (not shown) for the discharge of cement to the delivery conveyor  37 , thus bypassing the delivery conveyor  37  such that no dry cement will be delivered onto the cross conveyor  43 . 
   The shaft  62  is rotatably supported by spaced-apart bearings  71  that are mounted in the housing  52  at the distal end of the shaft  62  from the mixing plate  65 , as is best seen in  FIGS. 6 and 9 . The remote end  62   a  of the shaft  62  projects rearwardly from the end of the housing  52  for operable connection to a drive mechanism, preferably in the form of a hydraulic motor (not shown) supported form the end of the tubular portion  53  of the housing  52 . 
   A water inlet port  57  is connected to a conduit (not shown) to deliver water to the mixing housing  54  from the water tank  38  in discrete metered amounts. The water inlet port  57  is preferably located at the end of the tubular portion  53  near the junction between the tubular portion  53  and the mixing housing  54 . The water inlet port  57  supplies a flow of water into a water chamber  58  that is generally concentric around the auger  63  so that the water and cement do not become mixed until being introduced into the mixing housing  54 . 
   The mixing assembly  60  is operable to convey the metered cement from the metering mechanism  40  through the tubular portion  53  of the housing  52  by the rotation of the auger  63  working against the confines of the tubular portion  53 . Water is introduced into the mixing housing  54  through inlet openings  58   a  through the back wall  55  of the mixing housing, dividing the mixing housing  54  from the tubular housing  53 . Dry cement is carried into the mixing housing  54  by the auger  63  where the dry cement is mixed with the water in the manner described below. In an alternative embodiment, the water could be introduced into the end of the tubular housing  53  immediately next to the mixing housing  54 ; however, this procedure has presented more difficult problems with respect to cleaning of the turbine mixer  50  at the end of day. 
   The vertical back wall  55  of the mixing housing  54  is formed with a plurality of pegs  56  projecting generally perpendicularly from the back wall  55  into the mixing housing  54 . As is best seen in  FIG. 11 , the posterior or rearward face  66  of the mixing plate  65  is formed with radially oriented fins  67  at the outer circumference of the mixing plate  65  located to rotate with the mixing plate  65  around the periphery of the mixing housing  54  radially outwardly from and immediately adjacent to the pegs  56 . 
   As best seen in  FIG. 10 , the exterior or front face  68  of the mixing plate  65  is also formed with a plurality of radially oriented fins  69  mounted on the outer circumference of the mixing plate  65  in register with the fins  67 . Alignment of the fins  67 ,  69  is not critical to the operation of the mixing plate  65 , but provides a convenient configuration for manufacturing the mixing plate  65  and maintains balance for the rotation of the mixing plate  65 . The cover plate  70  is also formed with radially oriented blades  74  that are positioned radially inwardly of the rotating fins  69  and immediately adjacent to the path of movement of the fins  69 . The proximity of the fins  67 ,  69  to the corresponding pegs  56  and blades  74  provides for an agitation of the cement and water being conveyed into the mixing housing  54 , as will be described in greater detail below. 
   The mixing plate  65  is also formed with arcuate blades  64  spaced around the circumference of the shaft  62  on the posterior face  66 , and optionally on the exterior face  68 , to convey, upon rotation of the mixing plate  65 , any cement/water mixture radially outwardly toward the outer circumference of the mixing plate  65 . The arcuate blades  64  prevent cement mixture from accumulating at the center of the mixing housing  54  without being conveyed out of the mixing housing  54 . The arcuate blades  64  are positioned radially inwardly, respectively, of the corresponding pegs  56  on the back wall  55  of the mixing housing  54  and, if positioned on the exterior face  68  of the mixing plate  65 , radially inwardly of the blades  74  on the inside of the cover plate  70  to cause a greater agitated mixing of the cement and water before being discharged from the mixing housing  54 . 
   The mixing plate  65  has a smaller diameter than the outer cylindrical shell  61  of the mixing housing  54  to permit the fins  67 ,  69  to be rotated in close proximity to the outer shell  61  and to provide an annular gap  75  between the mixing plate  65  and the outer shell  61  for the passage of mixed, or partially mixed, cement and water from the posterior side  66  of the mixing plate  65  to the exterior side  69 . Thus, the mixing plate  65  divides the mixing housing  54  into an inner chamber and an outer chamber with the mixing plate  65  forming a barrier to the passage of cement and water from the inner chamber to the outer chamber. The annular gap  75  provides the only passageway for the agitated cement and water mixture to reach the outer chamber. 
   As best seen in  FIG. 10 , the discharge opening  59  is preferably positioned in the cover plate  70 , at a radially outwardly located position, in flow communication with the outer chamber to extract the agitated cement paste (cement/water mixture) from the outer chamber of the mixing housing  54 . Preferably, the discharge opening  59  will be an elongated oval to provide some adjustability in the operation of the turbine mixer  50 , as will be described in greater detail below. As seen in  FIGS. 10 and 12 , a slide adjustment plate  80  is mounted on the cover plate  70  in flow communication with the discharge opening  59 . The slide adjustment plate  80  is formed with a generally circular discharge opening  82  and slotted mounting holes  84  which are positioned to register with pins  88  fixed to the exterior surface of the cover plate  70 . 
   Thus, the slide adjustment plate  80  is adjustably positionable in a generally vertical manner relative to the discharge opening  59 . A seal, such as a rubber gasket (not shown) will be utilized between the slide adjustment plate  80  and the cover plate  70  to prevent the discharged cement slurry from leaking past the slide adjustment plate  80 . A discharge nozzle  86  can be connected to the discharge opening  82  for connection to a conduit (not shown) that would convey the ejected cement paste from the turbine mixer  50  to the mixing auger  42  for combining with the aggregates conveyed thereto via the cross conveyor  43  as described above. Preferably, the housing  52  will be mounted at a slightly inclined orientation to facilitate a draining of the mixing housing  54  toward the discharge port  59 . 
   The extent of hydration of the cement particles in the turbine mixer  50  can be controlled through the positional adjustment of the slide adjustment plate  80 . Moving the adjustment plate  80  to a position where the discharge opening  82  is in alignment with the radially outward extreme circumference of the discharge opening  59  in the cover plate  70  will retain a minimal amount of cement paste within the periphery of the shell  61  of the housing  54 . While the mixing action of the mixing plate  65  at the radially outward alignment position provides hydration results heretofore unknown in the concrete production industry, moving the adjustment plate  80  radially inwardly along the elongated discharge opening  59  such that the discharge opening  82  in the adjustment plate  80  is aligned with the inwardmost circumference of the discharge opening  59  substantially increases the power requirements and the mixing action of the turbine mixer  50 . 
   For a 13-inch diameter mixing housing  54  and a two-inch discharge opening  82  alignable with a three-inch long discharge opening  59 , the turbine mixer will require about 15-20 HP to operate. Moving the adjustment plate  80  to align the discharge opening  82  with the radially inwardmost diameter of the discharge opening  59  increases the power requirements by about 50%. Accordingly, the adjustment plate  80  will preferably have an indicator  85  associated therewith to indicate the position of the discharge opening  82  relative to the discharge port  59  to reflect the mixing effect that has been selected by the positioning of the slide adjustment plate  80 . 
   The assembled turbine mixer  50  will have the cover plate  70  bolted to the lugs  51  on the back wall  55  of the mixing housing  54  with the outer cylindrical shell  61  clamped therebetween. The auger  63  is rotatably driven by the hydraulic motor at high speeds, such as about 3000 RPM&#39;s, within the tubular portion  53  of the mixing housing  52  to convey dry cement received from the metering mechanism  40  in flow communication with the tubular portion  53  toward the mixing housing  54 . The mixing plate  65  is oriented internally of the mixing housing  54  and divides the mixing housing  54  into inner and outer chambers with the discharge port  59  in flow communication with the outer chamber such that the cement/water mixture has to pass through the annular gap  75  between the mixing plate  65  and the cylindrical outer shell  61  to be discharged from the mixing housing  54 . 
   The fins  67 ,  69  on the opposing faces  66 ,  68  of the mixing plate  65  cooperate in high speed rotation with the pegs  56  on the back wall  55  of the mixing housing  54  and, respectively, with the blades  74  on the posterior surface of the cover plate  70  to agitate the cement and water being conveyed into the mixing housing  54  into a fluid, homogeneous mixture that is conveyed from the housing  52  through the conduit (not shown) to the mixing auger  42 . As a result, a greater proportion of the individual cement particles become hydrated and air becomes mixed into the cement water slurry mixture before being conveyed to the mixing auger  42 . By breaking up the cement and water particles through the agitating action of the turbine mixer  50 , the chemical reaction between the cement and the water has an increased efficiency. Since a greater proportion of the cement particles are hydrated, the compressive strength of the finished concrete product from the mixing auger  42  will be higher. Furthermore, the bleed water in concrete as the concrete mixture is setting is reduced due to the higher proportion of hydration of the individual cement particles. 
   The operation of the turbine mixer  50  breaks up the dry cement into particles that are smaller in size than the water droplets that are created by the insertion of the water through the inlet openings  58   a  and the engagement thereof by the mixing plate  65 . As a result, the atomized cement particles become infused into the water droplets to create a greatly hydrated mixture of cement and water, a hydration action heretofore unknown in the concrete production industry. 
   One skilled in the art will recognize that the location of the turbine mixer  50  is not limited to being at the rear of the mobile concrete mixer  10 , as is depicted in  FIG. 3 , but may be located anywhere that dry cement can be conveyed into the tubular portion  53  of the housing  52  and the final cement and water slurry mixture can be conveyed to the mixing auger  42 . 
   The broad aspects of the instant invention relate to the high speed mixing of cement and water, as well as the pressure caused by the mixing, before being introduced into the mixing operation for combining the cement/water slurry with coarse and fine aggregate to produce a final concrete mixture. Such high speed agitated mixing action breaks the cement particles into a fine condition to be mixed with substantially atomized water to effect hydration of a high proportion of the cement particles heretofore unknown in the art of concrete production. 
   The dropping of the dry cement into the tubular portion  53  of the mixing housing  52  keeps the dry cement product from being exposed to the atmosphere, thus eliminating, or at least substantially reducing, the amount of cement dust that is released to the atmosphere during the production of concrete in a mobile concrete production system. Since the mixing action of the cement and water within the turbine mixer  50  entrains air into the cement/water slurry mixture, fewer requirements for air entrainment admixtures would likely be needed. The highly agitated mixing action created by the turbine mixer  50  should reduce or eliminate the false set phenomenon by increasing the mixing time and the hydration of the individual cement particles in the cement/water slurry. Accordingly, substantially any type of cement can be used in the operation of a mobile concrete production system. 
   The provision of the turbine mixer  50  allows for a more efficient use of admixtures for concrete. Adding a port  57   a  in communication with the water chamber  58  for the introduction of liquid admixtures into the housing  52  will permit the complete mixing of the admixture with the cement/water slurry mixture before being introduced into the mixing auger  42 . The addition of a color dye into the concrete mixture through an additional port  57   b  can also be introduced into the turbine mixer  50  to provide a uniform homogeneous mixing of the color dye throughout the cement/water slurry before being discharged into the mixing auger  42 . Since the high speed agitation of the cement and water causes a substantial dispersion of the agglomerated cement particles and an infusion of the cement particles into the water particles to create a more homogeneous slurry mixture than heretofore known, some admixtures will be activated more completely than heretofore known and may be reduced or even eliminated completely, particularly those admixtures used to decrease set time and increase compressive strength. 
   The utilization of a turbine mixer  50  to pre-mix the cement and water components for the production of concrete, particularly in mobile concrete production systems may require a change in the current standards by which concrete is now made. One skilled in the art will recognize that the principles of the instant invention are not limited in scope to only mobile concrete production systems, although the use of the turbine mixer  50  is highly advantageous in such an environment, the turbine mixer  50  can also be utilized in conventional batch production operations to increase the hydration of individual cement particles and to provide the advantages identified above. In fact, the utilization of the turbine mixer  50  in batch, or ready-mix, concrete production operations can completely revolutionize the entire concrete production industry. Tests have shown that concrete made with the cement and water pre-mixed by a turbine mixer  50  has approximately 15-20% greater compressive strength than corresponding conventionally prepared concrete. As a result, less cement would be required to provide concrete with the same strength specifications, providing a production cost savings. 
   The utilization of the turbine mixer for the batch or ready-mix concrete industry will require a larger turbine mixer structure than the representative structure shown and described above in conjunction with a mobile concrete production system. The principles of operation will be essentially identical for all types of concrete production except that the larger the size of the turbine mixer, the more power will be required to operate it. 
   It will be understood that changes in the details, materials, steps and arrangements of parts which have been described and illustrated to explain the nature of the invention will occur to and may be made by those skilled in the art upon a reading of this disclosure within the principles and scope of the invention. The foregoing description illustrates the preferred embodiment of the invention; however, concepts, as based upon the description, may be employed in other embodiments without departing from the scope of the invention.