Multi-layer concrete block for a surface covering laid in bond and surface covering

Abstract

A concrete block is described in the form of a surface covering element. The concrete block is made of at least one multi-layer concrete block body. The multi-layer concrete block body has a concrete block layer arranged on the concrete block top side, at least one second concrete block layer adjoining the first concrete block layer and a third concrete block layer adjoining the second concrete block layer. The third concrete block layer forms the concrete block underside. The second concrete block layer is a non-fines porous core layer. The first concrete block layer has a first porosity, the second concrete block layer has a second porosity, and the third concrete block layer has a third porosity, wherein a mean pore size of the pores in the third concrete block layer is smaller than the mean pore size of the pores in the second concrete block layer.

What is claimed is: 
     
         1 . A concrete block in a form of a surface covering element which can be laid in bond for producing a surface covering, comprising at least a multi-layer concrete block body with at least one concrete block underside and a concrete block top side opposite thereto, wherein the multi-layer concrete block body comprises at least one first concrete block layer arranged on the concrete block top side, at least one second concrete block layer adjoining the first concrete block layer and, a third concrete block layer adjoining the second concrete block layer, wherein the third concrete block layer forms the at least one concrete block underside, which is for laying on a bedding layer of a substrate, and wherein the second concrete block layer arranged between the first concrete block layer and the third concrete block layer is a non-fines porous core layer, wherein the first concrete block layer has a first porosity and comprises pores with a first pore size distribution, and the second concrete block layer has a second porosity and comprises pores with a second pore size distribution, and in that the third concrete block layer has a third porosity and comprises pores with a third pore size distribution, wherein a mean pore size of pores in the third concrete block layer is smaller than a mean pore size of pores in the second concrete block layer. 
     
     
         2 . The concrete block according to  claim 1 , wherein the mean pore size of the pores in the third concrete block layer corresponds to at most 0.3 times to 0.6 times of the mean pore size of the pores in the second concrete block layer. 
     
     
         3 . The concrete block according to  claim 1 , wherein the mean pore size of the pores in the first concrete block layer is smaller than the mean pore size of the pores in the second concrete block layer and the third concrete block layer. 
     
     
         4 . The concrete block according to  claim 1 , wherein the mean pore size of the pores in the first concrete block layer ( 2   a ) corresponds to at most 0.1 times to 0.3 times of the mean pore size of the pores in the second concrete block layer. 
     
     
         5 . The concrete block according to  claim 1 , wherein the mean pore size of the pores in the third concrete block layer corresponds to at least 3 to 4 times the mean pore size of the pores in the first concrete block layer. 
     
     
         6 . The concrete block according to  claim 1 , wherein the first concrete block layer, the second concrete block layer and the third concrete block layer comprises in each case a number of pores which exceed a minimum pore size, wherein the number of pores with at least the minimum pore size in the second concrete block layer and the third concrete block layer is the same, or substantially the same, or differs from one another by at most 10%. 
     
     
         7 . The concrete block according to  claim 6 , wherein the number of pores with the minimum pore size in the first concrete block layer is higher than in the second concrete block layer and the third concrete block layer. 
     
     
         8 . The concrete block according to  claim 1 , wherein the first concrete block layer, the second concrete block layer and the third concrete block layer in a totality of their respective pores in each case comprises pores with a maximum pore size, wherein the maximum pore size of the pores of the first concrete block layer is smaller than the maximum pore size of the pores of the second concrete block layer and the third concrete block layer, and/or in that the maximum pore size of the pores of the third concrete block layer is smaller than the maximum pore size of the pores of the second concrete block layer. 
     
     
         9 . The concrete block according to  claim 1 , wherein the second concrete block layer arranged between the first concrete block layer and the third concrete block layer is produced from a non-fines porous core concrete and the concrete block is designed to absorb and store water in the second concrete block layer. 
     
     
         10 . The concrete block according to  claim 1 , wherein the first concrete block layer, formed as a face concrete layer, is a dense-structure concrete block layer which is produced from an earth-moist concrete. 
     
     
         11 . The concrete block according to  claim 1 , wherein the third concrete block layer comprises a capillary suction effect for sucking water from the concrete block underside through the third concrete block layer into the second concrete block layer. 
     
     
         12 . The concrete block according to  claim 1 , wherein the third concrete block layer comprises a lower water permeability than the second concrete block layer and is designed in such a way that a gravity-induced water flow through the third concrete block layer is reduced in volume, in particular throttled. 
     
     
         13 . The concrete block according to  claim 1 , wherein the non-fines porous core layer comprises a water permeability of less than 1×10−5 m/s or a water permeability on average of less than 1.5×10−4 m/s and/or a compressive strength of at least 50 N/mm2. 
     
     
         14 . A surface covering comprising a plurality of multi-layer concrete blocks laid in bond on a bedding layer of a substrate according to any one of  claim 1 , wherein joints are formed between adjacent concrete blocks of the surface covering, and wherein the joints are filled with a substantially grit join material and/or sand joint material and form a seepage path for draining rainwater from a surface of the surface covering, and wherein the surface covering is equipped to absorb and store water in order to provide water for evaporation via the surface of the surface covering. 
     
     
         15 . A method for producing a concrete block according to  claim 1  comprising the steps of:
 providing a formwork: 
 introducing a concrete into the formwork in a first step to produce the third concrete block layer: 
 producing, in a second step, the second concrete block layer, wherein additionally non-fines porous core concrete is introduced into the formwork, and 
 producing, in a third step, the first concrete block layer, wherein a face concrete is introduced into the formwork, and wherein the concrete material introduced is subsequently compacted and cured.