Healing agent for self-healing cementious material

Abstract

The invention provides a process for the production of a cementious material. The process comprises mixing cement starting materials and a particulate healing agent to provide the cementious material. The healing agent comprises coated particles, wherein the coated particles comprise bacterial material and additive. The bacterial material is selected from the group consisting of a bacterium, a lyophilized bacterium and a bacterial spore of a bacterium. The present invention solves these problems, as (substantially leakage-proof) tablets containing the actual healing agent may neither interfere with either the workability of the liquid mixture (“cementious material”) nor negatively affect properties of either mixture or final material (hardened concrete), even when applied in large quantities. During crack formation in cementious based constructions, the particles also crack, and healing agent is released.

1 . A particulate healing agent for a cementious material, comprising coated particles having a mean diameter in the range of 0.2-4 mm and a coating thickness in the range of 5 μm-2 mm and comprising:
 (a) a bacterial material selected from the group consisting of bacterium, lyophilized bacterium and bacterial spore of bacterium; and 
 (b) an additive; 
 wherein the coated particles comprise at least 50 wt. % bacterial material and additive, relative to total weight of the coated particles, and 
 wherein the coating is configured to protect the particles during production of the cementious material comprising the particulate healing agent, but the particles are configured to break when cracks are formed during hardening of the cementious material to release the particulate healing agent into the cracks to at least partially heal the cracks. 
 
     
     
         2 . The particulate healing agent according to  claim 1 , wherein the additive comprises one or more compounds selected from the group consisting of calcium compounds, calcium formate, calcium acetate, calcium lactate, calcium gluconate, a carbohydrate, a fatty acid, an amino acid, a lactate, a maleate, a formate, a sugar, a pyruvate, a phytate, a yeast extract, a peptone, a carbohydrate, a fatty acid, an amino acid, a lactate, a glutamate, an aspartate, a maleate, a formate, a pyruvate, a sugar a phytate, and trace elements. 
     
     
         3 . The particulate healing agent according to  claim 1 , wherein the additive comprises:
 (1) one or more compounds selected from the group consisting of calcium formate, calcium acetate, calcium lactate, calcium gluconate, a carbohydrate, a fatty acid, an amino acid, a lactate, a maleate, a formate, a sugar, a pyruvate and a phytate, and   (2) a bacterial growth factor selected from the group consisting of a yeast extract, a peptone, an aspartate, a glutamate, and trace elements.   
     
     
         4 . The particulate healing agent according to  claim 1 , wherein the bacterium is selected from the group consisting of aerobic bacteria, and/or bacteria that can form a phosphate or a carbonate precipitate in an alkaline medium. 
     
     
         5 . The particulate healing agent according to  claim 1 , wherein the bacterium is selected from the group of genera consisting of  Planococcus, Bacillus  and  Sporosarcina.    
     
     
         6 . The particulate healing agent according to  claim 1 , wherein the weight ratio bacterial material:additive of the particulate healing agent is in the range of 1:10,000-1:1,000,000. 
     
     
         7 . (canceled) 
     
     
         8 . The particulate healing agent according to  claim 1 , wherein the coating comprises a (co)polymer based on one or more monomers selected from the group comprising glycolide, lactide, ε-caprolactone, δ-valerolactone, N-vinylcaprolactam, 3,6-dimethyl-1,4-dioxane-2,5-dione, glycosyloxyethyl methacrylate, 1,6-bis(p-acetoxycarbonylphenoxy)hexane and (3S)-cis-3,6-dimethyl-1,4-dioxane-2,5-dione. 
     
     
         9 . The particulate healing agent according to  claim 1 , wherein the coating comprises an epoxy based (co)polymer. 
     
     
         10 . The particulate healing agent according to  claim 1 , wherein the coated particles have a mean particle hardness in the range of 3-9 according to Mohs scale. 
     
     
         11 . (canceled) 
     
     
         12 . A particulate healing agent for a cementious material, comprising coated particles having a mean diameter in the range of 0.2-4 mm and a coating thickness in the range of 5 μm-2 mm and comprising:
 (a) a bacterial material selected from the group consisting of bacterium, lyophilized bacterium and bacterial spore of bacterium; and 
 (b) an additive, 
 wherein coating comprise a (co)polymer-based coating, and wherein the coated particles comprise at least 50 wt. % bacterial material and additive, relative to total weight of the coated particles, and 
 wherein the coating is configured to protect the particles during production of the cementious material comprising the particulate healing agent, but the particles are configured to break when cracks are formed during hardening of the cementious material to release the particulate healing agent into the cracks to at least partially heal the cracks. 
 
     
     
         13 . The particulate healing agent according to  claim 12 , wherein the additive comprises one or more compounds selected from the group consisting of calcium compounds, calcium formate, calcium acetate, calcium lactate, calcium gluconate, a carbohydrate, a fatty acid, an amino acid, a lactate, a maleate, a formate, a sugar, a pyruvate, a phytate, a yeast extract, a peptone, a carbohydrate, a fatty acid, an amino acid, a lactate, a glutamate, an aspartate, a maleate, a formate, a pyruvate, a sugar a phytate, and trace elements. 
     
     
         14 . The particulate healing agent according to  claim 12 , wherein the additive comprises:
 (1) one or more compounds selected from the group consisting of calcium formate, calcium acetate, calcium lactate, calcium gluconate, a carbohydrate, a fatty acid, an amino acid, a lactate, a maleate, a formate, a sugar, a pyruvate and a phytate and   (2) a bacterial growth factor selected from the group consisting of a yeast extract, a peptone, an aspartate, a glutamate, and trace elements.   
     
     
         15 . The particulate healing agent according to  claim 12 , wherein the bacterium is selected from the group of genera consisting of  Planococcus, Bacillus  and  Sporosarcina.    
     
     
         16 . The particulate healing agent according to  claim 12 , wherein the weight ratio bacterial material:additive of the particulate healing agent is in the range of 1:10,000-1:1,000,000. 
     
     
         17 . (canceled) 
     
     
         18 . The particulate healing agent according to  claim 12 , wherein the (co)polymer is based on one or more monomers selected from the group comprising glycolide, lactide, ε-caprolactone, δ-valerolactone, N-vinylcaprolactam, 3,6-dimethyl-1,4-dioxane-2,5-dione, glycosyloxyethyl methacrylate, 1,6-bis(p-acetoxycarbonylphenoxy)hexane and (3S)-cis-3,6-dimethyl-1,4-dioxane-2,5-dione. 
     
     
         19 . The particulate healing agent according to  claim 12 , wherein the coating comprises an epoxy based (co)polymer. 
     
     
         20 . (canceled) 
     
     
         21 . A cementious-based construction comprising hardened cementious material, the hardened cementious material further comprising bacterial material, wherein the bacterial material is selected from the group consisting of a bacterium, a lyophilized bacterium and a bacterial spore of a bacterium, wherein the bacterium is selected from the group of genera consisting of  Planococcus, Bacillus  and  Sporosarcina  and wherein the weight ratio hardened cementious material and bacterium is in the range of 1.10 6 :1-1.10 8 :1. 
     
     
         22 . The cementious-based construction according to  claim 21 , wherein the hardened cementious material is obtainable by a process comprising mixing cement starting materials and a particulate healing agent comprising:
 (a) a bacterial material selected from the group consisting of bacterium, lyophilized bacterium and bacterial spore of bacterium; and   (b) an additive,   wherein the healing agent comprises coated particles having a coating thickness in the range of 5 μm-2 mm.   
     
     
         23 . The cementious-based construction according to  claim 21 , wherein the hardened cementious material is obtainable by a process comprising mixing cement starting materials and a particulate healing agent comprising:
 (a) a bacterial material selected from the group consisting of bacterium, lyophilized bacterium and bacterial spore of bacterium; and   (b) an additive,   wherein the coated particles comprise a (co)polymer-based coating.   
     
     
         24 . The particulate healing agent according to  claim 22 , wherein the weight ratio cement starting materials and particulate healing agent is in the range of 2,000:1-20:1 (including water) and/or the weight ratio cement starting materials and bacterium is in the range of 1.10 6 :1-1.10 8 :1. 
     
     
         25 . A cementious material, comprising cement and the particulate healing agent of  claim 1  embedded in the cement. 
     
     
         26 . A hardened cementious material, comprising cement and the particulate healing agent of  claim 1  embedded in the cement.