Continuous methods of making fiber reinforced concrete panels

A continuous method for preparing a fiber reinforced concrete panel comprising:

• mixing water and dry cementitous powder to form a cementitous slurry, wherein the dry cementitious powder comprises at least one of Portland cement, calcium aluminate cements (CAC), calcium sulfoaluminate cements (CSA), geopolymers, magnesium oxychloride cements (sorel cements), and magnesium phosphate cements;
• mixing the cementitous slurry and reinforcement fibers in a single pass horizontal continuous mixer to form a fiber-slurry mixture of fiber reinforced cementitous slurry mixture,
• the single pass horizontal continuous mixer comprising:
• an elongated mixing chamber defined by a horizontal housing having an interior cylindrical side wall,
• at least one reinforcement fiber inlet port to introduce the reinforcement fibers through the interior cylindrical side wall directly into the mixing chamber, said reinforcement fibers comprises at least one of fiberglass, polymeric materials, polypropylene, polyethylene, polyvinyl alcohol, carbon, graphite, aramid, ceramic, steel or a combination thereof, and
• upstream of the at least one fiber inlet port is (a) at least one inlet port to introduce the water and the dry cementitous powder together as one stream through the interior cylindrical side wall directly into the mixing chamber or (b) at least two inlet ports to introduce the water and the dry cementitous powder separately as separate streams through the interior cylindrical side wall directly into the chamber,
• a fiber-slurry mixture outlet port at a downstream discharge end section of the horizontal housing to discharge the fiber reinforced cementitous slurry mixture, produced by the horizontal continuous mixer, laterally relative to the horizontal housing through an opening in the side wall of the horizontal housing into and through the fiber-slurry mixture outlet port on the horizontal housing,
• a venting port to remove any air introduced into the mixing chamber from raw material feed, and
• a rotating centrally horizontally oriented shaft mounted within the elongated mixing chamber traversing from one end of the horizontal continuous mixer to another end of the horizontal continuous mixer,
• wherein the cementitous slurry and reinforcement fibers are mixed in a part of the mixing chamber for mixing the reinforcement fibers and cementitous slurry and moving the cementitous slurry and reinforcement fibers being mixed to the fiber-slurry mixture outlet;
• wherein the centrally horizontally oriented shaft in the part of the mixing chamber for mixing the reinforcement fibers and cementitous slurry and moving the cementitous slurry and reinforcement fibers being mixed to the fiber-slurry mixture outlet comprises at least one mixing element selected from the group consisting of (1) an auger and (2) a plurality of mixing paddles mounted on the centrally horizontally oriented shaft at regular intervals and different circumferential locations to extend from the centrally horizontally oriented shaft, wherein the at least one mixing element rotates with the centrally horizontally oriented shaft within the housing;
• wherein the cementitous slurry and reinforcement fibers are mixed in the mixing chamber of the horizontal fiber-slurry mixer for an average mixing residence time of about 5 to about 240 seconds while the at least one mixing element applies shear force, wherein the centrally horizontally oriented shaft rotates at 30 to 450 RPM;
• discharging the fiber-slurry mixture laterally from the horizontal mixer through the opening in the side wall of the horizontal housing into and through the fiber-slurry mixture outlet port;
• wherein, simultaneous with the discharging of the water, the dry cementitous powder, and the reinforcement fibers forming the fiber-slurry mixture from the single pass horizontal continuous mixer, further water, cementitous powder which is dry or combined with the further water, and reinforcement fibers forming further fiber-slurry mixture are fed to the single pass horizontal continuous mixer;
• feeding the discharged fiber-slurry mixture to a forming assembly which deposits the fiber-slurry mixture on a moving surface of a panel production line uniformly as a layer 0.25 to 2 inches thick;
• leveling the fiber-slurry mixture on the moving surface;
• allowing the fiber-slurry mixture to set on the moving surface;
• cutting the set fiber-slurry mixture into panels and removing the panels from the moving surface, wherein an additional layer of fiber-slurry mixture is not deposited on the deposited layer of fiber-slurry mixture.