Method and device for filling a cavity with mortar

Abstract

The invention concerns a method which consists in mixing the mortar and a setting and hardening accelerator in a screw conveyor ( 13 ) and in pouring into the cavity ( 8 ) by gravity the resulting mixture through a chute ( 14, 28, 30).

1 . A method for filling a cavity ( 8 ) with a mortar capable of setting, at least one setting and hardening accelerator having to be added to said mortar, and said mortar being available at the unloading orifice of a transport vehicle ( 39 ) delivering it in the vicinity of said cavity ( 8 ), characterized in that 
 a first flux is formed, consisting of said mortar and being displaced in the direction of said cavity ( 8 );    a second flux is formed, consisting of said setting and hardening accelerator and being displaced in the direction of said first flux;    said second flux is added to said first flux, and said fluxes are mixed in order to amalgamate them into a third flux; and    said third flux is introduced by gravity into said cavity ( 8 ).    
   
   
       2 . The method as claimed in  claim 1 , characterized in that the flow rate of said second flux is adjusted as a function of the flow rate of said first flux in order to fix the proportion of setting and hardening accelerator in said third flux.  
   
   
       3 . The method as claimed in either  claim 1 , characterized in that said mortar is based on Portland cement, while the setting and hardening accelerator is based on calcium aluminates.  
   
   
       4 . The method as claimed in  claim 3 , characterized in that said Portland cement does not comprise mineral additives, such as fly ash or filler.  
   
   
       5 . The method as claimed in  claim 3 , characterized in that said setting and hardening accelerator has a C 12 A 7  content at most equal to 1%.  
   
   
       6 . The method as claimed in  claim 1 , characterized in that said setting and hardening accelerator takes the form of a powder.  
   
   
       7 . The method as claimed in  claim 1 , characterized in that said setting and hardening accelerator takes the liquid form of a slurry comprising setting inhibitors of said accelerator and, if appropriate, dispersants.  
   
   
       8 . The method as claimed in  claim 3 , characterized in that said mortar comprises approximately 100 kg/m 3  of cement, a water/cement ratio in the order of 2, only sand with a granulometry at most to 4 mm, and an air entrainer additive making it possible to obtain an air content in the order of 15% to 25% of the total volume.  
   
   
       9 . The method as claimed in  claim 1 , characterized in that the fluidity of said third flux is sufficiently high to ensure that the mixture of mortar and of setting and hardening accelerator of which it consists is self-placing, that is to say it flows freely into said cavity, at the same time coating the walls of the latter completely, and filling the entire volume of said cavity, without leaving any appreciable voids.  
   
   
       10 . A device for carrying out the method specified under  claim 1 , characterized in that it comprises: 
 a first receptacle ( 11 ) for receiving the mortar emerging from said unloading orifice of said transport vehicle ( 39 );    first means of advance ( 13 ) fed with mortar from said first receptacle ( 11 ) and forming said first flux;    a second receptacle ( 25 ) for receiving said setting and hardening accelerator;    second means of advance ( 13 ) fed with setting and hardening accelerator from said second receptacle ( 25 ) and forming said second flux;    means ( 13 ) for adding said second flux to said first flux and for mixing said fluxes, at the same time amalgamating them; and    third means of advance ( 13 ) fed from said amalgamation and mixing means ( 13 ) and forming said third flux of mortar and of setting and hardening accelerator, resulting from the amalgamation and mixing of said first and second fluxes.    
   
   
       11 . The device as claimed in  claim 10 , characterized in that said first and second means of advance, said amalgamation and mixing means and said third means of advance consist of a single endless screw conveyor ( 13 ).  
   
   
       12 . The device as claimed in  claim 11 , characterized in that said endless screw conveyor ( 13 ) is inclined relative to the horizontal, in that its lower end is fed with mortar from said first receptacle ( 11 ), in that its intermediate part is fed with setting and hardening accelerator from said second receptacle ( 25 ), and in that said third flux of mortar and of setting and hardening accelerator emerges from the side of the upper part of said endless screw conveyor ( 13 ).  
   
   
       13 . The device as claimed in  claim 12 , characterized in that it comprises a third receptacle ( 14 ) arranged under the upper part of said endless screw conveyor ( 13 ) and intended for receiving said third flux of mortar and of setting and hardening accelerator, and in that the lower part of said third receptacle is shaped as a chute ( 28 ,  29 ,  30 ) capable of introducing said third flux of mortar and of setting and hardening accelerator into said cavity ( 8 ).  
   
   
       14 . The device as claimed in  claim 10 , characterized in that the first, second and, if appropriate, third receptacles and also said first, second, third means of advance and said amalgamation and mixing means are carried by a chassis ( 2 ) provided with wheels ( 3 ,  4 ).  
   
   
       15 . The device as claimed in  claim 14 , intended for filling a trench ( 8 ) made in the ground ( 9 ), characterized in that said wheels ( 3 ,  4 ) are capable of coming to bear on the ground on either side of said trench ( 8 ).  
   
   
       16 . The device as claimed in  claim 15 , characterized in that it comprises means ( 34 ) for guidance along said trench.  
   
   
       17 . The device as claimed in  claim 15 , characterized in that it comprises a plate ( 35 ) integral with said chassis ( 2 ) and capable of functioning as a float.  
   
   
       18 . The method as claimed in  claim 1  for filling a cavity taking the form of a trench ( 8 ) made in the ground ( 9 ), said filling being carried out by means of the device ( 1 ) of one of  claims 14  to  17 , characterized in that said device ( 1 ) is displaced along said trench ( 8 ), and in that said first receptacle ( 11 ) is fed continuously with mortar by said transport vehicle ( 39 ) following a road parallel to said trench.  
   
   
       19 . The method as claimed in  claim 18 , characterized in that said device ( 1 ) and said transport vehicle ( 39 ) are coupled to a common tractor ( 37 ).