Microcapsules and concrete containing the same

Abstract

Microcapsules, for inclusion in concrete, adapted to reduce the area of a defect by at least 45% in said concrete once a quantity of said microcapsules has ruptured, said micro-capsules each comprising: a polymeric shell encapsulating a liquid core, wherein the polymeric shell comprises a substantially impermeable polymer layer and the liquid core comprises carbonatogenic bacterial spores, and optionally bacterial nutrients, dispersed in a liquid medium. Also disclosed is a concrete composition comprising a quantity of such microcapsules, and a method of reducing the area of a defect in concrete.

1 .- 39 . (canceled) 
     
     
         40 . Microparticles, for inclusion in a concrete, concrete-based, or concrete-like material, said microparticles each comprising:
 a core, in the form of a porous solid and/or a liquid;   carbonatogenic bacterial spores dissolved and/or dispersed in the core,   wherein said microparticles are adapted to reduce, or to assist in the reduction of, the area of a defect in said material by carbonatogenesis by the carbonatogenic bacteria once a quantity of said microparticles has fractured or is exposed at an interface of the defect.   
     
     
         41 . Microparticles as claimed in  claim 40 , further comprising:
 a shell surrounding the core.   
     
     
         42 . Microparticles as claimed in  claim 41  wherein the core of each of the microparticles comprises the porous solid. 
     
     
         43 . Microparticles as claimed in  claim 42 , wherein liquid is present in substantially all of the pores of the porous solid, and the carbonatogenic bacterial spores are dispersed in the liquid and bacterial nutrients are dispersed or dissolved in the liquid. 
     
     
         44 . Microparticles as claimed in 41, wherein the shell further comprises a polymer layer, the polymer further comprising melamine formaldehyde resin, the polymer having reactive functional groups, extending outwardly of the microparticle, whereby the microparticle is chemically bondable within the material. 
     
     
         45 . Microparticles as claimed in  claim 42  wherein the porous solid of each of the microparticles comprises a silica-based material or a carbohydrate-based material. 
     
     
         46 . Microparticles according to  claim 40 , wherein the microparticles are microcapsules, for inclusion in concrete, adapted to reduce the area of a defect in said concrete once a quantity of said microcapsules has ruptured or is exposed at an interface of the defect, said microcapsules each comprising:
 a polymeric shell encapsulating a liquid core,   wherein the polymeric shell comprises a substantially impermeable polymer layer and the liquid core comprises carbonatogenic bacterial spores dispersed in a liquid, and   wherein, in each microcapsule, the concentration of the bacterial spores is at least 109 spores per gram (dry weight) of microcapsule, such that, when a quantity of said microcapsules is present in concrete, the area of the defect therein is reducible by at least 45% as compared to an initial area of the defect once at least some of said quantity of microcapsules have been ruptured.   
     
     
         47 . A concrete, concrete-based, or concrete-like composition, comprising:
 a cementitious material;   one or more aggregate materials;   a liquid binder; and   a quantity of microparticles as claimed in  claim 40 .   
     
     
         48 . The composition of  claim 47 , wherein the core of each the microparticles is provided with a surrounding shell. 
     
     
         49 . The composition of  claim 48 , wherein the core of each of the microparticles comprises the porous solid. 
     
     
         50 . The composition of  claim 49 , wherein liquid is present in substantially all of the pores of the porous solid, and the carbonatogenic bacterial spores are dispersed in the liquid and bacterial nutrients are dispersed or dissolved in the liquid. 
     
     
         51 . The composition of  claim 48 , wherein the shell further comprises a polymer layer, the polymer further comprising melamine formaldehyde resin, the polymer having reactive functional groups, extending outwardly of the microparticles, whereby the microparticles are chemically bonded to the cementitious material. 
     
     
         52 . The composition as claimed in  claim 49  wherein the porous solid of each of the microparticles comprises a silica-based material or a carbohydrate-based material. 
     
     
         53 . The composition as claimed in  claim 49  wherein the microparticles are microcapsules adapted to reduce the area of a defect in the composition once a quantity of said microcapsules has ruptured or is exposed at an interface of the defect, said microcapsules each comprising:
 a polymeric shell encapsulating a liquid core, 
 wherein the polymeric shell comprises a substantially impermeable polymer layer and the liquid core comprises carbonatogenic bacterial spores dispersed in a liquid, and 
 wherein, in each microcapsule, the concentration of the bacterial spores is at least 109 spores per gram (dry weight) of microcapsule, such that the area of the defect in the composition is reducible by at least 45% as compared to an initial area of the defect once at least some of said quantity of microcapsules have been ruptured. 
 
     
     
         54 . A method of reducing the area of a defect in a concrete, concrete-based, or concrete-like material, the method comprising:
 providing a composition as claimed in  claim 47 ;   setting the composition; and   causing at least some of said quantity of microparticles to fracture in response to the creation and/or worsening of a defect in said set composition;   effecting defect reduction in said set composition by release of the contents of the quantity of microparticles followed by carbonatogenesis by the carbonatogenic bacteria.   
     
     
         55 . The method of  claim 54 , wherein each of the microparticles is provided with a surrounding shell. 
     
     
         56 . The method of  claim 55 , wherein
 the core of each of the microparticles comprises the porous solid.   
     
     
         57 . The method of  claim 56 , wherein liquid is present in substantially all of the pores of the porous solid, and the carbonatogenic bacterial spores are dispersed in the liquid and bacterial nutrients are dispersed or dissolved in the liquid. 
     
     
         58 . The method as claimed in  claim 54  wherein the porous solid of each of the microparticles comprises a silica-based material. 
     
     
         59 . The method as claimed in  claim 54  wherein the porous solid of each of the microparticles comprises a carbohydrate-based material.