Self-healing materials containing spores and oil-based protection of spores for concrete repair

Abstract

1. A self-healing material for repairing cracks in a cementitious material, the self-healing material comprising: a porous substrate having pores, the porous substrate comprising: a cementitious component disposed on at least a portion of a surface of the substrate, disposed within at least a portion of the pores of the substrate, or both; and fungal spores within at least a portion of the pores, the fungal spores being at least partially coated with a protective coating.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application No. 63 / 399,454, filed August 19, 2022, and U.S. Provisional Patent Application No. 63 / 401,869, filed August 29, 2022, each of which is incorporated herein by reference.

[0002] The present disclosure is directed to self-healing materials including spores for repairing cracks in cementitious materials such as concrete. The present disclosure is further directed to protecting the spores, such as by coating the spores with a protective coating. [Background technology]

[0003] Cementitious materials such as concrete can develop cracks for a variety of reasons. When such cracks are not adequately repaired, the concrete tends to have weakened strength, which can pose safety concerns. Unrepaired cracks also allow substances (e.g., water, air, salt) to penetrate the concrete. Additionally, unrepaired cracks can expose any reinforcing steel to corrosion and can create an undesirable appearance.

[0004] Some conventional techniques for repairing cracks, such as sealant injection, require frequent inspections to identify the cracks, making these and other conventional techniques difficult, time-consuming, and costly. Summary of the Invention [Problem to be solved by the invention]

[0005] There remains a need in the art for improvements to repair cracks in cementitious materials. [Means for solving the problem]

[0006] One aspect of the present disclosure provides a self-healing material for repairing cracks in a cementitious material, the self-healing material comprising: a porous substrate having pores, the porous substrate comprising a cementitious component disposed on at least a portion of a surface of the substrate, disposed within at least a portion of the pores of the substrate, or both; and fungal spores within at least a portion of the pores, the fungal spores being at least partially coated with a protective coating.

[0007] Another aspect of the present disclosure provides a method for self-repairing cementitious materials, the method comprising combining a porous substrate with a wet cement slurry; optionally removing a portion of the wet cement slurry, including excess water of the wet cement slurry; allowing the wet cement slurry to at least partially harden on the surface of the porous substrate, or at least partially harden within the porous substrate, or both; combining fungal spores at least partially coated with a protective coating with the porous substrate, thereby forming a spore-loaded porous substrate; and optionally further coating the spore-loaded porous substrate with a second protective coating.

[0008] Another aspect of the present disclosure provides a self-healing material for repairing cracks in cementitious materials, the self-healing material comprising: a porous substrate having pores, the porous substrate comprising a material selected from foam, expanded clay, celite, perlite, and foam glass; and fungal spores within at least a portion of the pores, the fungal spores being at least partially coated with a protective coating. DETAILED DESCRIPTION OF THE INVENTION

[0009] Cementitious materials such as concrete are prone to cracking, which can result in a variety of undesirable effects. Aspects of the present disclosure are directed to repairing such cracks. Aspects of the present disclosure are directed to self-healing materials for repairing cracks in cementitious materials such as concrete.

[0010] As further described herein, the term "self-healing material" generally refers to an assembly including a carrier material containing spores. As further described, the spores have the ability to enable the repair of cracks in cementitious materials. The carrier material of the self-healing material generally serves to physically protect the spores. The spores in the self-healing material can also be chemically protected by coating the spores with a protective coating before incorporating the coated spores into the carrier material.

[0011] As described further herein, the term cementitious material generally refers to a material that is a cement-based material, which may also be referred to as a cement-containing material or a material having the properties of cement, including self-repairing materials. Cementitious materials may also be referred to herein as cementitious compositions or composites. Exemplary cementitious materials include concrete, cementitious coatings, and mortar. Exemplary structures that can be made from concrete include tunnels, bridges, and slabs for roads, airports, and warehouses. While aspects of the present disclosure may refer specifically to concrete, it should be understood that these aspects can extend to other suitable cementitious materials.

[0012] Incorporation of spores into the cementitious material via the self-healing material should enable the spores to survive and remain dormant throughout the damaging conditions to which the cementitious material is subjected. These conditions can include conditions to which the cementitious material may be subjected throughout various stages of its formation and across a wide range of environments.

[0013] After one or more cracks appear in a cementitious material (e.g., a concrete structure) and the spores are exposed to suitable conditions, such as receiving oxygen and appropriate nutrients, the spores should then germinate to return to vegetative growth as vegetative cells. The vegetative cells, which may also be called microorganisms, should then form a solid deposit, which may also be called a mineral, to repair the one or more cracks. This process of producing a solid deposit by microorganisms is commonly known as biomineralization. The produced solid deposit should act to sufficiently fill the one or more cracks so that the self-healing material disclosed herein can repair the cracks in the cementitious material.

[0014] That is, the term self-repairing material, which may also be referred to as a self-healing material, generally refers to the ability of a material to repair itself, including the cementitious material, which may also be said to have an innate ability to repair damage. This repair ability may also include not requiring external diagnosis of the problem and not requiring further human intervention to repair the damage.

[0015] In other words, cementitious materials including self-repairing materials can compensate for cracks through biomineralization, particularly by initiating spore germination, followed by vegetative growth by cells resulting from the germination, and then filling the cracks with solid material resulting from the vegetative growth, which may include not needing to add additional materials such as sealants.

[0016] In one or more embodiments of the present disclosure, the self-repairing material can be mixed with an initial cementitious material, where the initial cementitious material refers to the composition that becomes the final cementitious material. For example, the initial wet cementitious material can become the final dry, hardened cementitious material (e.g., concrete is a cementitious material that includes cement and aggregate, and thus the final cementitious material may be hardened concrete). In these or other embodiments of the present disclosure, the self-repairing material may fill cracks in an already-existing final cementitious material. In these or other embodiments of the present disclosure, a coating including the self-repairing material and the cementitious material may be applied to an already-existing final cementitious material. Exemplary thicknesses for a coating including the self-repairing material and the cementitious material include about 5 mm to 20 mm, or about 5 mm to 15 mm, or about 5 mm to 10 mm, or about 10 mm to 15 mm.

[0017] As discussed above, attempts to repair cementitious materials (e.g., concrete) can be complicated due to the harsh conditions to which the cementitious material may be subjected, particularly during the formation of the cementitious material, which may also be referred to as cement hydration. Conditions during cement hydration may include a relatively high pH, ​​e.g., up to about pH 13, and a relatively high temperature, e.g., up to about 50°C to 60°C. Cement hydration generally involves the cementitious slurry changing from a liquid state to a hard or solid state. After the formation of the cementitious material, the formed cementitious material may be exposed to harsh environmental conditions.

[0018] Thus, the components of the self-healing materials disclosed herein generally need to withstand such conditions. As discussed further herein, aspects of the present disclosure are directed to protecting the spores from these conditions, such as by coating the spores with a protective coating and / or by including the spores in a carrier material.

[0019] In addition to the need for spores and microorganisms to withstand these harsh conditions, consideration of suitable spores and microorganisms should generally take into account certain other factors. Suitable species of spores and microorganisms, as well as aspects of cementitious materials, can be selected based on one or more of the following: the ability of the spores to remain dormant and viable for a relatively long period of time while trapped in the cementitious material (e.g., concrete); the ability of the spores to germinate and grow under the conditions (e.g., temperature, humidity, and salinity) when cracks appear in the cementitious material; the ability of the microorganisms to produce a sufficient amount of solid deposit to repair the crack when in a vegetative growth state; compatibility with the overall cementitious material, such as the self-repairing material, any corresponding components, and solid deposit; the ability of the components of the self-repairing material and any corresponding components to be available to the microorganisms to form solid deposits; and the ability of the microorganisms to generate or return to a dormant state after the crack has been repaired to provide subsequent re-germination to carry out repeated repair steps.

[0020] As mentioned above, aspects of the present disclosure relate to self-repairing materials that include spores produced by microorganisms, and corresponding cementitious materials that include the self-repairing materials. As is generally known to those skilled in the art, spores are small, single-celled structures that are mostly inactive and dormant. Spores are produced by microorganisms for dispersal and long-term survival, and therefore generally can withstand harsh environmental conditions.

[0021] Spores are distinguished from vegetative cells, which are actively growing cells. Spores in self-healing materials and corresponding cementitious materials must germinate within the original vegetative cells to produce a solid deposit. Because spores are initially dormant, their ability to germinate under conditions expected in cracks in cementitious materials should be considered. Dormancy is generally maintained in uncracked cementitious materials due to a relatively high pH (e.g., >12) and lack of oxygen in the uncracked cementitious material. Cracks in cementitious materials generally tend to reduce the pH (e.g., <10), allowing sufficient oxygen and water to reach the spores to end their dormancy. Ending dormancy generally also requires providing sufficient nutrients, also referred to as food, to the spores via the self-healing material and / or corresponding cementitious material. Aspects related to providing these appropriate nutrients are disclosed elsewhere herein.

[0022] Suitable microorganisms and spores can be screened and selected against the factors disclosed regarding the suitability of certain microorganisms and spores to be utilized in the self-healing materials and corresponding cementitious materials disclosed herein.

[0023] It has generally been found that fungal spores, which may also be called fungal aerial spores or conidia, perform better than bacterial spores in achieving the functions disclosed herein. For example, fungal spores have a relatively high survival rate in concrete. Fungal spores may also generally produce more solid deposits. As another example, some bacteria produce internal endospores, which may require difficult collection techniques. Thus, much of this disclosure focuses on suitable fungal spores. However, certain bacterial spores may be utilized in accordance with the functions disclosed herein.

[0024] In embodiments of the present disclosure, suitable species of fungal spores include those that have sufficient cell growth at a relatively high pH, ​​such as about 10 or about 11, for surface growth, such as on agar plates. In embodiments of the present disclosure, suitable species of fungal spores include those that do not produce harmful amounts of organic acids. Such organic acids are produced by some fungi and cause localized pH drops, and it is believed that these microbial organic acids can adversely affect the integrity of concrete and cause corrosion of any rebar. In embodiments of the present disclosure, suitable species of fungal spores include those that have the ability to grow submerged in liquid media with a relatively high pH, ​​such as about 10 or about 11. In embodiments of the present disclosure, suitable species of fungal spores include those that have the ability to germinate at a moderately high pH, ​​such as about 9.5, which is suitable for cementitious environments under ambient air carbonation, such as within cracks. In embodiments of the present disclosure, suitable species of fungal spores include those capable of spore germination at neutral to moderately high pH after exposure to high pH and / or temperature conditions associated with those encountered during the mixing, setting, and curing of cementitious materials (e.g., concrete), such as a pH of about 12.9 and temperatures of 45° C. to 55° C. In embodiments of the present disclosure, suitable species of fungal spores include those that meet many or all of these conditions.

[0025] Suitable species for fungal spores will be those that produce solid materials (e.g., calcium carbonate, such as calcite). This should include the ability to form continuous, large pieces of solid deposits. Additionally, the calcite formation morphology and its relationship to cellular biomass should be considered in selecting suitable species for fungal spores. Another consideration for solid materials may include the ability to produce coprecipitates (e.g., SrCO).

[0026] In aspects of the present disclosure, suitable species of fungal spores include alkaliphilic and / or alkali-tolerant fungi.

[0027] In embodiments of the present disclosure, suitable species of fungal spores include Scopulariopsis brevicaulis, Purpureocillium lilacinum, Myrothecium verrucaria, Aspergillus nidulans, and combinations thereof. With reference to the USDA-ARS Culture Collection (NRRL), examples include Aspergillus nidulans NRRL 187, Scopulariopsis brevicaulis NRRL 1100, Myrothecium verrucaria NRRL 2003, and Purpureocillium lilacinum NRRL 895.

[0028] As mentioned above, fungal spores can be protected from harsh conditions through a protective coating, which may also be referred to as chemical protection. In embodiments of the present disclosure, spores can be individually coated with a protective coating. Embodiments of the present disclosure also include multiple spores embedded in a single coating.

[0029] The protective coating can be applied to the spores by suspending them in the desired material for the protective coating, which can be one or more oils, which can also be referred to as a hydrophobic liquid or hydrophobic coating. In one or more embodiments, the protective coating includes one or more free fatty acids in addition to one or more oils. The one or more free fatty acids can be used to lower the local pH, such as when the spores are in a cementitious material. The spore coating can also be referred to as an oil-surrounded spore. The coated spores can be provided for subsequent use in the form of an oil suspension, which can also be referred to as a spore-containing oil phase.

[0030] As mentioned above, the protective coating should generally be hydrophobic, which may be referred to as a hydrophobic liquid. The hydrophobic surface of the fungal spore allows for easy coating with a layer of the hydrophobic coating. The hydrophobic coating generally serves to prevent or minimize contact between the spore and water. The hydrophobic coating is typically a hydroxide (OH - It is also believed that the hydrophobic coating protects the spores from higher pH environments because the ) ions are insoluble in oil and therefore the effects of high pH are inaccessible to the spores within the coating. The hydrophobic coating also serves as a carrier liquid, allowing spores to be placed within porous substrates, as described further herein. Additionally, the hydrophobic coating can also serve to be consumable by fungal cells, such as after spore germination in cracked cementitious materials (e.g., concrete, mortar), in support of fungal cell growth and biomineralization.

[0031] Many suitable substances and mixtures can be used in the protective coating. Exemplary materials for the protective coating include oils, free fatty acids, and melted fats, including solutions and mixtures thereof. Those skilled in the art will also understand that the term "oil" as used herein can refer to compositions having a variety of chemical components. Exemplary oils include soybean oil, palm oil, rapeseed oil, canola oil, olive oil, sunflower oil, coconut oil, corn oil, cottonseed oil, peanut oil, safflower oil, mineral oil, paraffin oil, liquid hydrocarbons, and mixtures thereof having a chain length of about C10 to about C25, and silicone oils. Exemplary free fatty acids include oleic acid, palmitic acid, stearic acid, linoleic acid, and linolenic acid. Exemplary free fatty acids may also be referred to as long-chain fatty acids, generally referring to chain lengths of about C10 to about C25. Other suitable hydrophobic liquids include animal-based, plant-based, petroleum-derived, and synthetic hydrophobic liquids. Still other suitable hydrophobic liquids include other lipids and oil-soluble or oil-compatible compounds, such as fatty alcohols, ethers, esters, glycolipids, and lipopeptides. Still other suitable materials include monoglycerides and diglycerides.

[0032] Other suitable materials for the protective coating include compounds with functional groups that provide sufficiently low water solubility. Exemplary functional groups include alcohols, aldehydes, esters, amines, and amides. Sufficiently low water solubility can generally be less than 1 g / L, such as at ambient conditions. Still other suitable materials for the protective coating include compounds with carboxylic acid functional groups (—COOH).

[0033] Materials for the protective coating can be selected depending on the desired end use. For example, an oily material may be selected based on its ability to be consumed by microorganisms or for its appropriate melting point. Furthermore, one or more fatty acids can form insoluble salts with alkali and alkaline to neutralize localized high pH and minimize damage to spores. Any formation of insoluble salts with alkali and alkaline, also referred to as saponification, should also be balanced with the properties of the cementitious material. This may include the use of certain additives, such as air release agents, to reduce the amount of unwanted or excessive air in order to reduce saponification and / or prevent any saponification-related issues. As mentioned above, a mixture of one or more oils, one or more fatty acids, and / or one or more melted fats may be utilized to achieve two or more of these specific benefits.

[0034] As described above, the fungal spores of the self-healing material are provided through impregnation or incorporation into a carrier material, which may also be referred to as a carrier substrate. The carrier material should be porous to allow the spores to be impregnated or incorporated therein. The porous carrier material containing the spores may also be referred to as a spore-loaded porous substrate. This inclusion of the spores within the carrier / substrate serves as a form of physical protection for the spores. In one or more embodiments, this impregnation or incorporation of the spores into the carrier material occurs after the spores have been coated with a protective coating. The carrier material should receive the spores within its internal pores and / or within the surface pores, and their presence within the surface pores may be referred to as being coated on the carrier material.

[0035] In one or more embodiments, the porous carrier material is a plurality of porous particles. That is, the plurality of porous particles can be dispersed in the cementitious material. Each of the plurality of porous particles generally contains spores for repairing cracks at various locations of the plurality of porous particles.

[0036] Exemplary porous carrier materials include foams. Suitable foams will generally contain open cells. Open cells are believed to allow for easier penetration, such as for spore impregnation. This may also be referred to as open-cell foam, which is more porous and absorbent than closed-cell foam. Furthermore, open-cell structures generally contain interconnected pores, thereby allowing for effective spore loading, even reaching the core of the pore-containing foam structure.

[0037] In an embodiment of the present disclosure, the foam can be made of polyurethane. As is generally known to those skilled in the art, polyurethane materials can be produced from the reaction of an A-side reactant with a B-side reactant. The A-side reactant typically includes an isocyanate compound (e.g., methylene diphenyl diisocyanate (MDI)), while the B-side reactant typically includes an isocyanate-reactive compound, such as a polyol. By mixing the A-side and B-side, the A-side and B-side reactants undergo a chemical reaction to form the polyurethane material via a chemical mechanism known to those skilled in the art.

[0038] Suitable isocyanate compounds include aliphatic, cycloaliphatic, araliphatic, and aromatic polyisocyanates. Suitable isocyanate-reactive compounds include polyesters, polyesteramides, polythioethers, polycarbonates, polyacetals, polyolefins, and polysiloxanes. Additives that may be included in one or both of the A and B sides include catalysts, surfactants, foam stabilizers, flame retardants, smoke suppressants, UV stabilizers, colorants, microbial inhibitors, and fillers. Other details of suitable polyurethane foams will generally be known to those skilled in the art.

[0039] Other exemplary materials for the foam include polyester and polyamide. Other exemplary materials for the foam include EPDM (ethylene propylene diene terpolymer), PVC / nitrile (polyvinyl chloride and nitrile rubber blend), ceramic, and metal (such as aluminum and nickel). Other suitable foams having sufficient absorption and strength may also be generally known to those skilled in the art.

[0040] Porous carrier materials such as foams offer a wide range of options with respect to properties such as compressive strength, hydrophilicity / hydrophobicity, pore size, surface energy, and porosity / density, etc. Those skilled in the art will generally know how to tailor these properties to achieve the functions described herein.

[0041] Exemplary pore sizes for foams include about 250 μm to about 750 μm, or about 300 μm to about 600 μm, or about 400 μm to about 700 μm, or about 400 μm to about 600 μm. These ranges generally refer to statistical distributions of pore sizes that will be commonly known to those skilled in the art. Exemplary median average pore sizes for foams include about 300 μm, or about 400 μm, or about 500 μm, or about 600 μm, or about 700 μm. Pore sizes can be determined from analyzing photomicrographs of the foam, which can be from a scanning electron microscope (SEM) or optical microscope.

[0042] Exemplary porosities for foams include at least 90%, at least 95%, at least 98%, and at least 99%. Exemplary porosities for foams include about 90%, about 95%, about 98%, and about 99%. Porosity can be measured by water absorption techniques.

[0043] As mentioned above, the hydrophilicity / hydrophobicity of the foam may be considered and adjusted. As discussed further herein, the hydrophilicity / hydrophobicity of the foam may be considered with respect to the properties and function of the wet cement slurry combined with the foam. That is, the foam may be immersed in a wet cement slurry to strengthen the foam. Thus, the hydrophilicity / hydrophobicity of the foam may be tailored to promote adhesion of the solids of the wet cement slurry along the fibers of the foam. It is generally desirable to achieve this adhesion rather than have the wet cement slurry form beads. If the foam is too hydrophobic, the wet aqueous cement slurry may attempt to form beads that can repel the foam. Therefore, if the beads are too large or the pores are too small, this beading can detrimentally reduce the space available for spores to fill the pores. In one or more embodiments, the foam may have a water contact angle of less than about 90 degrees, less than about 85 degrees, or less than about 80 degrees.

[0044] In addition to foams, other exemplary materials for the porous carrier material include expanded clay, celite, perlite, and foam glass. Still other materials may be suitable for the porous carrier material, which should generally provide sufficient strength as well as generally consistent porosity.

[0045] Exemplary compressive strengths for porous support materials include from about 90 psi to about 2,000 psi, or from about 150 psi to about 1,500 psi, or from about 200 psi to about 1,000 psi. Exemplary compressive strengths for porous support materials include at least 250 psi, or at least 500 psi, or at least 750 psi, or at least 1,000 psi. The desired compressive strength can be tailored based on the particular materials utilized for the porous support material.

[0046] When the porous carrier material is a composite of a foam and a cementitious component, as discussed further herein, exemplary compressive strengths for the composite material include from about 200 psi to about 900 psi, or from about 300 psi to about 800 psi, or from about 400 psi to about 700 psi, or from about 500 psi to about 600 psi. Exemplary compressive strengths for the composite material as a carrier material include at least 300 psi, or at least 400 psi, or at least 500 psi, or at least 600 psi, or at least 700 psi.

[0047] As mentioned above, the porous support material may be a plurality of porous particles. This refers to each porous particle, which generally has porosity, rather than the interparticle spaces that provide the porosity. The porous particles, which may also refer to length, may have a size of about 1 mm to about 10 mm, or about 1 mm to about 7 mm, or about 2 mm to about 6 mm, or about 3 mm to about 5 mm, or about 2 mm to about 5 mm, or about 2 mm to about 3 mm, or about 1 mm to about 5 mm, or about 1 mm to about 3 mm. In embodiments of the present disclosure, the porous particles may have a size of about 2 mm, or about 3 mm, or about 4 mm, or about 5 mm, or about 6 mm, or about 7 mm.

[0048] The plurality of porous particles may include porous particles of any suitable shape. Exemplary shapes for porous particles include those that are approximately cubic (or cubic-like), approximately spherical (or spherical-like), approximately rectangular (or prismatic), approximately cylindrical (or cylindrical-like), and combinations thereof. For shapes with two or more different dimensional measurements (i.e., different lengths, widths, and / or heights), the above dimensions may be utilized for each of the different dimensional measurements.

[0049] The shape of the porous particles may also be described in terms of aspect ratio. In one or more embodiments, the aspect ratio of the porous particles can be from about 1 to about 5, or from about 1 to about 4, or from about 1 to about 3, or from about 1 to about 2. In one or more embodiments, the aspect ratio of the porous particles can be about 1, or about 2, or about 3.

[0050] The shape of the porous particles may also be described in terms of sphericity. In one or more embodiments, the sphericity of the porous particles can be from about 0.6 to about 1, or from about 0.7 to about 1, or from about 0.75 to about 1, or from about 0.7 to about 0.95, or from about 0.75 to about 0.95, or from about 0.7 to about 0.9. In one or more embodiments, the sphericity of the porous particles can be greater than 0.6, or greater than 0.7, or greater than 0.8, or greater than 0.9, or greater than 0.95.

[0051] Some materials for the porous carrier material, such as polyurethane foam, may be easily compressible, especially those with high porosity and large pores. As such, these materials alone may not provide sufficient rigidity to protect the spores placed therein from physical damaging factors. Also, care should be taken to protect the impregnated spores as a whole from subsequent extrusion.

[0052] Thus, as described above, the self-healing materials of the present disclosure include a porous carrier material (i.e., a porous matrix) that includes a cementitious component for strength. The cement incorporated within and / or onto the porous carrier material may be referred to herein as the "cementitious component." Accordingly, aspects of the present disclosure include injecting, which may also be referred to as impregnation or incorporation, of a cementitious component in the form of a wet cement slurry into and / or onto a porous carrier material (e.g., a plurality of polyurethane foam particles). Impregnation will generally be achieved by immersing or soaking the porous carrier material in a cement slurry that includes at least cement and water. This incorporation of cement into the porous carrier material will generally serve to provide the porous carrier material with improved strength. A material that includes a porous matrix and a cementitious component, but does not include spores, may also be referred to herein as a "hybrid porous matrix and cement composite."

[0053] The incorporation of the wet cement slurry into and / or onto the porous carrier material can be assisted by mechanical forces. This can include mechanical devices that compress and then release the porous carrier material while it is in the cement slurry. These actions generally serve to rapidly flow the slurry, thereby transporting more cement particles into the porous carrier material. In one or more embodiments, this compression and release (i.e., decompression) technique is performed at least once, or at least twice, or at least three times, or at least four times. In one or more embodiments, this compression and release technique is performed 2 to 6 times, or 2 to 5 times, or 2 to 4 times, or 3 to 5 times. These repetitions of the compression and release technique can also be used to characterize the soaking time. That is, the soaking time can be sufficient to achieve the desired number of cycles of the compression and release technique. After the porous carrier material is removed from the cement slurry, additional compression and release techniques can be performed, which can be one, two, or three times. Compaction and release techniques can be utilized to remove some of the excess water during exit from the cement slurry.

[0054] The wet cement slurry utilized as the cementitious component for impregnating the porous substrate will generally comprise cement and water. In aspects of the present disclosure, the wet cement slurry utilized to impregnate the porous substrate can be adapted for compatibility with the subsequent composition for the cementitious material. For example, the wet cement slurry utilized to impregnate the porous substrate can be designed for compatibility with the concrete composition in which the hybrid porous substrate and cement composite that ultimately becomes the self-healing material will be utilized.

[0055] An exemplary weight ratio for the composition of a wet cement slurry for impregnating a porous substrate is about 0.5:1 water:cement. In other embodiments, the weight ratio for the composition of a wet cement slurry for impregnating a porous substrate can be about 0.25:1 to about 0.75:1 water:cement, or about 0.4:1 to about 0.6:1, or about 0.5:1 to about 0.6:1, or about 0.3:1 to about 0.5:1 water:cement.

[0056] Impregnation of the wet cement slurry into the porous carrier material is intended to deposit the wet cement along and / or between the pores in the foam structure, which may also be referred to as deposition on the surface foam or "fibers." The wet cement slurry may also provide at least a partial coating of the porous substrate.

[0057] The wet cement slurry within the pores and / or as a coating will then begin to harden, which may also be referred to as setting. This hardening or setting initiation is also referred to as being partially hardened or partially set. The porous carrier matrix will thus have partially set cement filled within and / or coated on its porous structure. The hardened cement will thus provide additional mechanical strength to the hybrid porous matrix and cement composite.

[0058] Hardening or setting of cement will involve at least partial hydration of the cement. At least partial hydration of the cement can involve the use of appropriate curing conditions, which generally involve maintaining the hardened cement under moist conditions and at a satisfactory temperature. This curing can include the application of additional water, which can be liquid water or steam.

[0059] Hardening or setting of the cement can include an air-drying or curing step, which can be the first step. In one or more embodiments, air-drying occurs for about 1 hour to about 6 hours, or about 2 hours to about 5 hours, or about 3 hours to about 4 hours.

[0060] Hardening or setting of the cement can include a steam curing step, which can follow an air drying step. Steam curing can include utilizing a steam curing chamber. In one or more embodiments, steam curing is performed for about 2 to about 8 hours, or about 3 to about 7 hours, or about 4 to about 6 hours.

[0061] The hardened cement does not completely fill most of the pores in the porous matrix. That is, the hardened cement reduces the initial pore size to a reduced pore size. The remaining pores are necessary for later impregnation of the hybrid porous matrix and cement composite with spores to form the self-healing material of the present disclosure. That is, the remaining pores should still be well connected and large enough for effective spore loading. Some pores, especially those on the surface, may be entirely covered by the hardened cement. Many pores should remain open, but the open pores should remain connected to other open pores.

[0062] As an example, the initial foam (e.g., polyurethane) can have a pore size of about 500 μm, and the open pores of the hybrid porous matrix and cement composite can remain about 200 μm after the wet cement slurry has hardened. In these or other embodiments, the initial foam can have a pore size of about 250 μm to 750 μm, or about 300 μm to 700 μm, or about 400 μm to 600 μm. In these or other embodiments, the open pores of the hybrid porous matrix and cement composite can remain about 50 μm to 350 μm, or about 100 μm to 300 μm, or about 150 μm to 250 μm after the wet cement slurry has hardened. These ranges generally refer to statistical distributions of pore sizes that will be commonly known to those skilled in the art. Pore sizes can be determined from analysis of photomicrographs of the foam, which can be from a scanning electron microscope (SEM) or optical microscope.

[0063] In other words, the porosity of the initial foam will be reduced after the incorporation of the hardened cement. In one or more embodiments, the hybrid porous matrix and cement composite can have a porosity of about 50% to about 90%, or about 55% to about 85%, or about 60% to about 80%, or about 60% to about 75%, or about 60% to about 70%, or about 65% to about 75%.

[0064] As described above, fungal spores can be protected through impregnation or incorporation into a carrier material. If the carrier material (e.g., foam) is reinforced with a cementitious component (e.g., cement slurry), this incorporation of spores into the carrier material should occur after the carrier material has been reinforced with the cementitious component. Incorporation of spores after the carrier material has been reinforced with the cementitious component generally serves to improve spore retention during the impregnation step. Impregnation or incorporation of spores into the carrier material can be achieved by dumping or immersing the spores into the carrier material. As described above, impregnation of spores into the carrier material can occur after the spores have been chemically protected with a protective coating. That is, one or more embodiments include providing the spores in a suspension of a protective coating material and then immersing the carrier material, which may include hardened cement, in the spore-containing suspension. This incorporation of spores into the carrier material thereby produces a self-healing material for subsequent incorporation by the cementitious material.

[0065] The self-healing material may be characterized by the amount of spores therein. As described herein, the spores are generally provided within a protective coating, which may include spores provided in a suspension in the material for the protective coating, which may be referred to as an oil-spore suspension or oil-spore solution. Thus, the amount of spores in the self-healing material may be referred to as the amount of oil-spore suspension retained by the self-healing material.

[0066] In other words, suitable porosities for the hybrid porous substrate and cement composite are provided above. With respect to these porosities, in one or more embodiments, about 70% to about 98%, or about 75% to about 95%, or about 80% to about 90%, or about 80% to about 95%, or about 85% to about 95% of the available void space can be filled with the oil-spore suspension. As an example, for a hybrid porous substrate and cement composite with an available porosity of about 60% to about 75%, and if about 75% to about 95% of the available void space is filled with the oil-spore suspension, multiplying these values ​​results in the self-healing material in these embodiments having a total volume of about 45% to about 71.25% of the oil-spore suspension.

[0067] To calculate the amount of oil-spore suspension in the self-healing material, the porosity in the hybrid porous matrix and cement composite (i.e., in the hardened state) can first be measured by water absorption. Once this porosity is determined, the hybrid porous matrix and cement composite can be measured before and after combining (e.g., soaking) with the oil-spore suspension to determine what percentage of the available porosity is filled by the oil-spore suspension.

[0068] Those skilled in the art will generally appreciate additional details for adapting and developing cementitious materials (e.g., concrete) that can utilize the self-repairing materials of the present disclosure. However, certain details are provided herein in this regard. As noted above, a cementitious material can refer to an initial composition having a self-repairing material incorporated therein, such that the incorporated self-repairing material can repair a final composition resulting from the initial composition. In other aspects, a cementitious material can refer to an already-existing final cementitious material into which the self-repairing material is incorporated, such as into existing cracks therein.

[0069] Compositions for cementitious materials generally include a binder (e.g., cement), aggregate, water, and, optionally, other desired additives generally known to those skilled in the art. Exemplary other additives include those that enhance the rheological properties and / or the speed of the curing process.

[0070] Aggregates are inert granular materials such as sand, gravel, stone, shells, and recycled concrete. The shape and surface texture of the particles can be considered for the properties of the freshly mixed concrete. The desired properties of the hardened concrete will also be considered. Aggregates can comprise about 60% to about 75% of the volume of the concrete.

[0071] Portland cement can be utilized as a binder, which may also be referred to as a binding material. Other exemplary binders include lime, hydraulic lime, and natural cement. Other exemplary binders include those commonly known as supplemental cementitious materials (SCM). Exemplary supplemental cementitious materials include industrial waste products such as granulated blast furnace slag and silica fume.

[0072] To provide effective spore-based self-healing protection to all or selected portions of objects and structures made of cementitious materials, the spores can be evenly distributed over the objects and structures or desired portions of the objects and structures. For example, if it is most desirable to self-heal the surface of a cementitious material, the spores can be evenly distributed within a surface layer of a desired thickness. That is, the core or center of the cementitious material cannot contain spores, and the surface layer will contain spores. Those skilled in the art will understand the use of a scaffold or casing to create a core without spores and a subsequent surface layer with spores. Exemplary thicknesses for a surface layer comprising a self-healing material and a cementitious material include about 5 mm to 20 mm, about 5 mm to 15 mm, about 5 mm to 10 mm, or about 10 mm to 15 mm. In other embodiments, the spores can be evenly distributed throughout the cementitious material, which may be desirable for certain newly constructed cementitious materials.

[0073] In other words, the cementitious material should contain the porous carrier matrix, and thus the spores, in a manner that results in a substantially uniform distribution throughout all or desired portions of the cementitious material. In this manner, the spores will be available in most or all desired spots where cracks may form. Thus, the size of the porous carrier particles may be considered, for example, in relation to achieving this function of substantially uniform distribution in relation to one or more other desired functions disclosed herein. That is, in embodiments of the present disclosure, relatively small sized porous particles may be used to achieve better distribution in the cementitious material, but this particle size should be balanced with other factors.

[0074] As mentioned above, in addition to concrete, other cementitious materials could potentially utilize self-repairing materials, including cementitious coatings and mortars.

[0075] Cementitious materials that include self-repairing materials can be characterized by the amount of self-repairing material therein. In embodiments of the present disclosure, the cementitious material includes 0.25% to about 5% by volume, 0.25% to about 2.5% by volume, or 0.5% to about 2% by volume, or 0.5% to about 1.5% by volume, or 1.0% to about 1.5% by volume, or 0.75% to about 1.5% by volume of the self-repairing material. In embodiments of the present disclosure, the cementitious material includes about 0.5% by volume, or about 1.0% by volume, or about 1.5% by volume, or about 2% by volume, or about 2.5% by volume of the self-repairing material.

[0076] In an embodiment of the present disclosure, the cementitious material comprises 0.05% to about 3% by weight, or 0.1% to about 2.5% by weight, or 0.2% to about 2% by weight, or 0.4% to about 1.5% by weight, or 0.25% to about 0.75% by weight, or 0.5% to about 1% by weight of the self-repairing material. In an embodiment of the present disclosure, the cementitious material comprises about 0.25% by weight, or about 0.5% by weight, or about 0.75% by weight, or about 1% by weight, or about 1.25% by weight of the self-repairing material.

[0077] The self-healing material (e.g., porous foam particles containing cementitious components and spores) can also be protected from harsh conditions through an additional protective coating, which may be referred to as a second protective coating, on the self-healing material. That is, the spore-containing porous foam particles can be coated with a protective coating. The protective coating can be applied to the self-healing material by suspending the self-healing material in the desired liquid composition of the second protective coating.

[0078] The second protective coating can include one or more free fatty acids. This can include a single type of free fatty acid or a mixture of various types of free fatty acids. The second protective coating can also include other suitable substances, such as one or more oils. These include solutions and mixtures thereof, such as one or more free fatty acids mixed with one or more oils. The one or more oils may be used to aid in the applicability of the second protective coating. The second protective coating can be applied in paste form. Exemplary free fatty acids include oleic acid, palmitic acid, stearic acid, linoleic acid, and linolenic acid. Exemplary oils include soybean oil, palm oil, rapeseed oil, canola oil, olive oil, sunflower oil, coconut oil, corn oil, cottonseed oil, peanut oil, safflower oil, mineral oil, paraffin oil, liquid hydrocarbons and mixtures thereof with chain lengths of C10 to C25, and silicone oils.

[0079] As noted above, the second protective coating can be a mixture of different types of free fatty acids or a single type of free fatty acid. A mixture of different types of free fatty acids may be utilized to achieve the desired consistency, although a single type of free fatty acid may also be suitable.

[0080] In one or more embodiments, the mixture of free fatty acids can comprise about 5% to about 50% by weight stearic acid, or about 10% to about 30% by weight stearic acid, or about 15% to about 20% by weight stearic acid. In one or more embodiments, the mixture of free fatty acids can comprise about 5% to about 50% by weight palmitic acid, or about 10% to about 30% by weight palmitic acid, or about 15% to about 20% by weight palmitic acid. In one or more embodiments, the mixture of free fatty acids can comprise about 25% to about 80% by weight oleic acid, or about 40% to about 75% by weight oleic acid, or about 60% to about 70% by weight oleic acid.

[0081] The protective coating on the self-healing material may be characterized by its thickness. In one or more embodiments, the protective coating on the self-healing material can have a thickness of about 50 μm to about 500 μm, or about 50 μm to about 250 μm, or about 75 μm to about 200 μm, or about 100 μm to about 150 μm, or about 100 μm to about 500 μm, or about 200 μm to about 500 μm.

[0082] As described above, self-repairing materials and cementitious materials initially contain dormant spores. The spores should be able to survive and remain dormant until one or more cracks appear in the cementitious material. After one or more cracks appear in the cementitious material and after being subjected to appropriate conditions, such as receiving oxygen and appropriate nutrients, the spores should germinate to return to vegetative growth as vegetative cells. Aspects of nutrients that can be provided by the protective coating and / or in the composition for the cementitious material are provided below. Sufficient oxygen provided by the cracks will support the respiratory needs of vegetative fungal cells.

[0083] After spore activation, vegetative cells from the spores of the self-healing material will produce a newly formed solid material, which may also be referred to as a residue from the self-healing material, a biomineralization product, or a bio-based composite. The newly formed solid material may be a mixture of biomass (i.e., cells and reformed spores), calcite, and other components. The production of the newly formed material should then repair the crack, and the newly formed material is deposited inside the crack.

[0084] One or more of the self-repairing material and the cementitious material should be provided with sufficient nutrients to support cells (e.g., fungal cells). As described above, the protective coating material (e.g., oil, fatty acid) may be selected based on its ability to be consumed by fungal cells as nutrients. In addition to the protective coating material, other nutrients can be added to the composition for the cementitious material. In one or more embodiments, nutrients can be provided in the self-repairing material. Thus, the self-healing material of the present disclosure may further include exemplary nutrients disclosed below instead of or in addition to any nutrients that may be provided by the protective coating. The amount of nutrients should be such that adequate repeatability of crack repair is provided, but too much nutrients may result in a cementitious material with relatively low strength. Those skilled in the art will be able to apply nutrients in accordance with the present disclosure.

[0085] Exemplary nutrients, which may also be referred to as growth nutrients, include calcium, urea, molasses / syrup obtained from processing soybeans, corn, and / or other agricultural crops, flour / meal obtained from processing soybeans, corn, and / or other agricultural and animal (including poultry) products, hull / husk powder obtained from processing soybeans, corn, and / or other agricultural crops, starch, cellulose, pectin, xylan, or other polysaccharides obtained from processing soybeans, corn, and / or other agricultural crops, and / or sources of certain essential micronutrients such as manganese, cobalt, copper, and zinc. The type and amount of nutrients can depend on the desired end use, particularly the intended number of self-repair cycles, the lifespan of the cementitious material / structure, the intended crack size, and the extent of repair. Calcium can be provided to support the formation of a desired amount of biomass and calcite. Urea can be provided to support the formation of even more calcite using fungal urease.

[0086] Although aspects of the present disclosure are discussed above, certain exemplary aspects are now provided.

[0087] Aspect 1. A self-healing material for repairing cracks in a cementitious material, the self-healing material comprising: a porous substrate comprising pores, the porous substrate comprising a cementitious component disposed on at least a portion of a surface of the substrate, disposed within at least a portion of the pores of the substrate, or both; and fungal spores within at least a portion of the pores, the fungal spores being at least partially coated with a protective coating.

[0088] Aspect 2. The self-repairing material of Aspect 1, wherein the cementitious component is cement.

[0089] Aspect 3. The self-repairing material of Aspect 2, wherein the cement is selected from Portland cement and natural cement.

[0090] Aspect 4. The self-repairing material of any of the above aspects, wherein the cementitious component is an at least partially hardened cement obtained from a cement slurry.

[0091] Aspect 5. The self-repairing material of any of the above aspects, wherein the cementitious component is a fully hardened cement obtained from a cement slurry.

[0092] Aspect 6. The self-healing material of any of the preceding aspects, wherein the fungal spores are of a species selected from Scopulariopsis brevicaulis, Purpureoscillium lilacinum, Myrothecium verrucaria, Aspergillus nidulans, and combinations thereof.

[0093] Embodiment 7. The self-healing material of any of the above embodiments, wherein the porous matrix comprises a plurality of porous particles.

[0094] Embodiment 8. The self-healing material of any of the above embodiments, wherein the porous substrate comprises foam.

[0095] Embodiment 9. The self-healing material of embodiment 8, wherein the foam comprises polyurethane.

[0096] Embodiment 10. The self-healing material of any of embodiments 7 to 9, wherein the plurality of porous particles have a length of about 2 mm to about 5 mm.

[0097] Embodiment 11. The self-healing material of any of the preceding embodiments, wherein the protective coating comprises an oil selected from soybean oil, palm oil, rapeseed oil, canola oil, olive oil, sunflower oil, coconut oil, corn oil, cottonseed oil, peanut oil, safflower oil, mineral oil, paraffin oil, silicone oil, and mixtures thereof, and wherein the protective coating is obtained from an oil-spore suspension comprising the oil and fungal spores.

[0098] Embodiment 12. The self-healing material of any of the above embodiments, wherein the protective coating comprises a free fatty acid.

[0099] Embodiment 13. The self-healing material of any of the above embodiments, wherein the porous substrate comprises a second protective coating on a surface thereof, the second protective coating comprising a mixture of free fatty acids.

[0100] Aspect 14. A cementitious material comprising the self-repairing material of any of the above aspects.

[0101] Aspect 15. The cementitious material of Aspect 14, wherein the cementitious material is selected from concrete, cementitious coatings, and mortars.

[0102] Aspect 16. The cementitious material of Aspect 15, further comprising a binder and an aggregate.

[0103] Aspect 17. A method for self-repairing a cementitious material, the method comprising combining a porous substrate with a wet cement slurry; optionally removing a portion of the wet cement slurry, including excess water therefrom; allowing the wet cement slurry to at least partially harden on the surface of the porous substrate, or at least partially harden within the porous substrate, or both; combining fungal spores at least partially coated with a protective coating with the porous substrate, thereby forming a spore-loaded porous substrate; and optionally further coating the spore-loaded porous substrate with a second protective coating.

[0104] Embodiment 18 The method of embodiment 17, further comprising combining the spore-loaded porous substrate with a cementitious material.

[0105] Embodiment 19. The method of any of Embodiments 17-18, wherein there is a step of removing a portion of the wet cement slurry.

[0106] Embodiment 20 The method of any of embodiments 17 to 19, wherein there is a step of further coating the spore-loaded porous substrate with a second protective coating.

[0107] Aspect 21. The method of any of Aspects 17 to 20, wherein the fungal spores are of a species selected from Scopulariopsis brevicaulis, Purpureoscillium lilacinum, Myrothecium verrucaria, Aspergillus nidulans, and combinations thereof.

[0108] Embodiment 22 The method of any of embodiments 17 to 21, wherein the wet cement slurry is allowed to fully harden before combining the fungal spores with the porous substrate.

[0109] Embodiment 23. The method of any of embodiments 17 to 22, wherein the allowing step comprises air drying the wet cement slurry.

[0110] Aspect 24. The method of Aspect 23, wherein the allowing step includes an air drying step followed by a steam curing step, and the fully set wet cement is defined by the air drying step occurring for about 3 to about 4 hours and the steam curing step occurring for about 4 to about 6 hours.

[0111] Embodiment 25. The method of any of embodiments 17 to 24, wherein the protective coating comprises an oil selected from soybean oil, palm oil, rapeseed oil, canola oil, olive oil, sunflower oil, coconut oil, corn oil, cottonseed oil, peanut oil, safflower oil, mineral oil, paraffin oil, silicone oil, and mixtures thereof, and the protective coating is applied to the fungal spores by incorporating the spores in the oil, thereby forming an oil-spore suspension.

[0112] Embodiment 26 The method of any of embodiments 17 to 25, wherein there is a step of further coating the spore-loaded porous substrate with a second protective coating, wherein the second protective coating comprises a mixture of free fatty acids.

[0113] Embodiment 27 The method of embodiment 26, wherein the mixture of free fatty acids comprises oleic acid, stearic acid, and palmitic acid.

[0114] Embodiment 28 The method of any of embodiments 17 to 27, wherein there is a step of further coating the spore-loaded porous substrate with a second protective coating, wherein the second protective coating has a thickness of about 100 μm to about 150 μm.

[0115] Aspect 29. A self-healing material for repairing cracks in a cementitious material, the self-healing material comprising: a porous substrate having pores, the porous substrate comprising a material selected from foam, expanded clay, celite, perlite, and foam glass; and fungal spores within at least a portion of the pores, the fungal spores being at least partially coated with a protective coating.

[0116] In light of the foregoing, it should be appreciated that the present invention advances the art by providing improved materials and compositions for repairing cracks in cementitious materials. While particular aspects of the invention have been disclosed in detail herein, it should be understood that the invention is not limited thereto or thereby, so long as variations thereon will be readily apparent to those skilled in the art. The scope of the invention is to be understood from the claims that follow. [Example]

[0117] screening Fungal strains were tested based on four screening tests, as further detailed below. A literature review was first performed to understand the distribution of fungi in high pH environments and to establish a list of potential alkaliphilic and alkali-tolerant fungi with a reported ability to grow at pH ≥ 8.5. Fungi documented as pathogens of plants, animals, and humans were avoided. Eighteen strains were then selected and obtained from the NRRL culture collection (Agricultural Research Service, US Department of Agriculture). The 18 strains were: Aspergillus glaucus NRRL 66587, Aspergillus thermomutatus NRRL 180, Aspergillus nidulans NRRL 187, A. nidulans NRRL 194, Paecilomyces variotii NRRL 1115, Scopulariopsis brevicaulis NRRL 1100, Trichoderma reesei NRRL 3652, T. reesei NRRL 6156, Myrothecium verrucaria NRRL 2003, Gliomastix murorum NRRL 62986, and Purpureoscillium lilacinum NRRL 1100. The isolates were Gliocladium virens NRRL 2308, Gliocladium sp. NRRL 22971, Cladosporium cladosporioides NRRL 3182, Penicillium expansum NRRL 62431, Penicillium citrinum NRRL 756, Chrysosporium sp. NRRL 22978, and Aspergillus niger NRRL 341.None of these strains required a USDA APHIS (Animal and Plant Health Inspection Service) Plant Protection and Quarantine (PPQ) 526 permit or a Veterinary Services (VS) 16-3 permit. Fungal cultures were maintained on potato dextrose agar (PDA, 40 g / L, pH 7) (Sigma Aldrich 70139).

[0118] Four screening tests were utilized. After each test, strains that met the test conditions were tested for subsequent conditions. The first test involved determining which strains had sufficient cell growth capacity at a relatively high pH, ​​such as about 10 or about 11. The second test involved determining which strains did not produce harmful amounts of organic acids. The third test involved determining which strains had the ability to germinate at a moderately high pH, ​​such as about 9.5, relative to a cementitious environment under ambient air carbonation, such as inside a crack. The fourth test involved determining which strains had the ability for spore germination at neutral to moderately high pH after exposure to high pH and / or temperature conditions relative to those encountered during mixing, setting, and curing of cementitious and cementitious compositions, such as a pH of about 12.9 and temperatures of 45°C to 55°C.

[0119] Based on these four screening tests, the most suitable species for fungal spores were found to be Scopulariopsis brevicaulis, Purpureoscillium lilacinum, Myrothecium verrucaria, and Aspergillus nidulans.

[0120] Screening Test 1 Potato dextrose agar (PDA, 40 g / L) plates at three pH values ​​were used: pH 7 was used as a control, and pH 10 and 11 were used for growth at high pH. pH 10 and 11 plates were prepared with 10 mM (for pH 10) and 20 mM (for pH 11) sodium carbonate-bicarbonate buffer. Cells were inoculated into the center of PDA plates and grown at room temperature (21 ± 2°C). Expanding colony diameters were measured with slide calipers on days 2, 4, and 6 for four plates of each fungal strain, and the mean and standard deviation were determined.

[0121] Screening Test 2 Growth was monitored in 100 mL of potato dextrose broth (PDB, 40 g / L) (Sigma Aldrich P6685) prepared in a 250 mL Erlenmeyer flask. The initial pH was adjusted to 10 using 0.1 M NaOH. No buffer solution was used because the study was also intended to investigate pH drop due to acid production by the fungus during growth in high-pH liquid medium. The flasks were covered with cotton wrapped in cheesecloth. After inoculation, the flasks were placed on a shaker (Innova 4080 Digital Incubator Shaker, New Brunswick Scientific Co., Inc.) at 125 RPM, and pH change was monitored every 8 hours for 4 days. A control without fungal inoculation was also prepared to measure the abiotic pH drop of the medium. Cell growth was observed (but not quantified) with the naked eye and confirmed by light microscopy.

[0122] Screening Test 3 A small amount of spores was generated for each strain tested. The inoculated PDA plates were grown at room temperature for 14 days. Mycelium covered the plates and was assumed to have sporulated. 30 mL of 1 g / L sterile aqueous Tween 80 (Fisher Scientific T164) solution was added to the plates, and spores were gently scraped from the culture with a sterile wire loop. 1 mL of the collected spore suspension was inoculated into a 250 mL Erlenmeyer flask containing 100 mL of PDB buffered to pH 12 with 0.025 M NaHPO and 0.027 M NaOH. The flask was covered with cotton wrapped in cheesecloth and shaken at 125 RPM. Samples were then taken every 8 hours and examined microscopically for spore germination. The time required for spores to germinate was recorded. A control with PDB at an initial pH of 6.5 was also prepared and inoculated with spores in the same manner to compare spore germination in neutral and high pH media.

[0123] Screening Test 4 PDB was prepared to have an initial pH of 12 or 12.9. pH 12 medium was buffered with 0.05 M NaHPO and 0.054 M NaOH, and pH 12.9 medium was buffered with 0.064 M KCl and 0.136 M NaOH. Spore suspensions were generated as described in Test 3. 1 mL of spore suspension was added to 9 mL of PDB in a 20 mL glass scintillation vial (Kimble 74504-20). A strip of Teflon tape (Anti-Seize 26135, low-density PTFE-thread seal tape) was wrapped around the vial neck, and the cap was tightly closed. Tightly capped vials were used to minimize pH drop due to carbonation. The evaluation tests showed that the pH dropped to 9.5-9.9 in 4 days for the cheesecloth-wrapped, cotton-covered shake flasks used in Test 3, but after 28 days it was only 11.2±0.6 for the closed-cap vials.

[0124] To simulate the high pH-temperature conditions in concrete preparations, the spore-loaded vials were placed in water baths at 45 and 55°C, respectively, or at room temperature (control) for 2 hours. The vials were then kept at room temperature and observed for spore germination under these high pH conditions for up to 21 days (simulating the concrete curing period). These vials are hereafter referred to as "storage" vials. For storage vials without spore germination, the vials were sacrificed weekly to collect the spores and washed once with deionized water (17,672 g) at 12,000 RPM for 10 minutes in a Thermo Scientific Sorvall Legend X1R. The washed spores were re-inoculated in PDBs at pH 6.5 (control) and 9.5 (simulating carbonated pH conditions in concrete cracks), respectively, and observed for spore germination. These latter sets of vials are referred to as "germination" vials. Two storage vials and two germination vials were prepared for each germination test time in PDB at each pH (6.5 or 9.5) and for each strain stored in PDB at each pH (12 or 12.9) and subjected to each heat treatment condition (room temperature, 45°C, or 55°C). [Example]

[0125] Viability test for S. brevicaulis spores Ordinary Portland cement and sand were dry-heat sterilized in a furnace at 150°C for 4 hours and then mixed with autoclaved deionized water in a cement:sand:water ratio of 1:2.75:0.5 by weight. A thin layer (approximately 45 mL) of this wet mortar mixture was added to two sterile Petri dishes. Five mL of S. brevicaulis spore suspension was then carefully added to the top of the mortar layer using a pipette. The system thus consisted of a layer of aqueous spore suspension on top of a layer of wet mortar that had undergone cement hydration. Samples were taken from the spore suspension with a sterile wire loop on days 3, 6, 9, 14, 21, and 28 and inoculated onto PDA to observe spore germination. pH was also measured / estimated for the sampled spore suspension using pH paper (Hydrion, Micro Essential Lab).

[0126] In another viability test on S. brevicaulis spores, it was found that exposure to a pH of up to 12 did not significantly add further damage to S. brevicaulis spores exposed to 55° C., but exposure to a pH of 12.9 caused substantial damage to S. brevicaulis spores exposed to 55° C. These results support aspects of the present disclosure in which a protective coating is utilized as a spore protection mechanism to slightly lower the local pH around the spores, as disclosed herein above. [Example]

[0127] Stability of spores in contact with oils and fatty acids. Several specific examples provided evidence for the long-term stability of spores in contact with protective coatings (e.g., oil, fatty acids, and oil-fatty acid mixtures). In one example, S. brevicaulis spores were stored in soybean oil at room temperature for three months and then inoculated onto potato dextrose agar plates. Spores in all inocula germinated, demonstrating the stability of spores in soybean oil suspension.

[0128] In another example, S. brevicaulis spores were incubated for two months in a mixture of soybean oil and fatty acids: 9 g oleic acid, 3 g stearic acid, and 2 g palmitic acid mixed with 3 mL of soybean oil. All spores germinated when inoculated onto potato dextrose agar plates. [Example]

[0129] Spores in polyurethane foam cubes Small pieces of open-cell, porous polyurethane foam were cut into cubes approximately 5 mm in size. These polyurethane cubes were then immersed in a water-cement mixture / slurry containing water and cement in a weight ratio of approximately 0.5:1 water:cement. The immersed cubes were subjected to a compression and release technique to aid in the addition of cement to the cubes and to aid in the removal of excess water / slurry. The cement-impregnated polyurethane cubes were allowed to stand in ambient air for one day to allow cement hydration to occur, then cured in water for three weeks, and then dried in ambient air for two weeks.

[0130] S. brevicaulis spores in a soybean oil suspension were then loaded into cured cement-reinforced polyurethane cubes by immersion. The spore-loaded cubes were then mixed with a mixture of fatty acids (66.7% oleic acid, 16.65% stearic acid, and 16.65% palmitic acid; by weight) to form a relatively thin oil-fatty acid coating of 100–150 μm around the cubes. These cubes were then immersed in multiple Petri dishes containing freshly prepared wet cement mortar (water:cement:sand = 0.5:1:2.75; by weight). The cubes were embedded in the wet cement mortar. Sacrificed mortar pieces were crushed after various setting and curing durations, and the recovered spore-containing polyurethane cubes / fragments were placed on potato dextrose agar plates to observe spore germination. Tests were carried out in mortar for periods up to 19 months and spore germination occurred from all polyurethane cubes / pieces tested.

[0131] Various modifications and alterations that do not depart from the scope and spirit of this invention will be apparent to those skilled in the art. This invention is not to be duly limited to the illustrative embodiments set forth herein.

Claims

1. 1. A self-healing material for repairing cracks in cementitious materials, comprising: a porous substrate having pores, a cementitious component disposed on at least a portion of a surface of the porous matrix, disposed within at least a portion of the pores of the porous matrix, or both; fungal spores within at least a portion of said pores, at least partially coated with a protective coating; the porous substrate comprising Self-healing materials, including:

2. The self-repairing material of claim 1 , wherein the cementitious component is cement.

3. 3. The self-repairing material of claim 2, wherein the cement is selected from Portland cement and natural cement.

4. 10. A self-repairing material according to any of the preceding claims, wherein the cementitious component is an at least partially hardened cement obtained from a cement slurry.

5. 10. A self-repairing material according to any of the preceding claims, wherein the cementitious component is a fully hardened cement obtained from a cement slurry.

6. 10. The self-healing material of any of the preceding claims, wherein the fungal spores are of a species selected from Scopulariopsis brevicaulis, Purpureocillium lilacinum, Myrothecium verrucaria, Aspergillus nidulans, and combinations thereof.

7. 10. The self-healing material of any of the preceding claims, wherein the porous matrix comprises a plurality of porous particles.

8. 10. The self-healing material of any preceding claim, wherein the porous matrix comprises a foam.

9. The self-healing material of claim 8 , wherein the foam comprises polyurethane.

10. 10. The self-healing material of claim 7, wherein the plurality of porous particles have a length of about 2 mm to about 5 mm.

11. 10. The self-healing material of any of the preceding claims, wherein the protective coating comprises an oil selected from soybean oil, palm oil, rapeseed oil, canola oil, olive oil, sunflower oil, coconut oil, corn oil, cottonseed oil, peanut oil, safflower oil, mineral oil, paraffin oil, silicone oil, and mixtures thereof, and wherein the protective coating is obtained from an oil-spore suspension comprising the oil and the fungal spores.

12. 10. The self-healing material of any of the preceding claims, wherein the protective coating comprises a free fatty acid.

13. 10. The self-healing material of any of the preceding claims, wherein the porous substrate comprises a second protective coating on a surface thereof, the second protective coating comprising a mixture of free fatty acids.

14. 10. A cementitious material comprising a self-repairing material according to any of the preceding claims.

15. 15. The cementitious material of claim 14, wherein the cementitious material is selected from concrete, cementitious coatings, and mortars.

16. 16. The cementitious material of claim 15, further comprising a binder and an aggregate.

17. 1. A method for self-repairing a cementitious material, comprising: combining the porous matrix with a wet cement slurry; Optionally, removing a portion of the wet cement slurry, including excess water of the wet cement slurry; allowing the wet cement slurry to at least partially harden on the surface of the porous matrix, or at least partially harden within the porous matrix, or both; combining fungal spores at least partially coated with a protective coating with said porous substrate, thereby forming a spore-loaded porous substrate; and Optionally, further coating the spore-loaded porous substrate with a second protective coating. A method comprising:

18. 18. The method of claim 17, further comprising combining the spore-loaded porous matrix with a cementitious material.

19. 19. The method of claim 17 or 18, wherein there is the step of removing a portion of the wet cement slurry.

20. 20. The method of any of claims 17-19, wherein there is a step of further coating the spore-loaded porous substrate with the second protective coating.

21. 21. The method of any of claims 17 to 20, wherein the fungal spores are of a species selected from Scopulariopsis brevicaulis, Purpureoscillium lilacinum, Myrothecium verrucaria, Aspergillus nidulans, and combinations thereof.

22. 22. The method of any of claims 17 to 21, wherein the wet cement slurry is allowed to fully harden prior to the step of combining the fungal spores with the porous matrix.

23. 23. The method of any of claims 17 to 22, wherein the allowing step comprises air drying the wet cement slurry.

24. 24. The method of claim 23, wherein the allowing step includes the air drying step followed by steam curing, and wherein the fully set wet cement is defined by the air drying step occurring for about 3 to about 4 hours and the steam curing step occurring for about 4 to about 6 hours.

25. 25. The method of any of claims 17 to 24, wherein the protective coating comprises an oil selected from soybean oil, palm oil, rapeseed oil, canola oil, olive oil, sunflower oil, coconut oil, corn oil, cottonseed oil, peanut oil, safflower oil, mineral oil, paraffin oil, silicone oil, and mixtures thereof, and wherein the protective coating is applied to the fungal spores by placing them in the oil, thereby forming an oil-spore suspension.

26. 26. The method of any of claims 17-25, wherein there is a step of further coating the spore-loaded porous substrate with a second protective coating, and wherein the second protective coating comprises a mixture of free fatty acids.

27. 27. The method of claim 26, wherein the mixture of free fatty acids comprises oleic acid, stearic acid, and palmitic acid.

28. 28. The method of any of claims 17-27, wherein the step of further coating the spore-loaded porous substrate with the second protective coating is present, and the second protective coating has a thickness of about 100 μm to about 150 μm.

29. 1. A self-healing material for repairing cracks in cementitious materials, comprising: a porous substrate having pores, the porous substrate comprising a material selected from foam, expanded clay, celite, perlite, and foam glass; fungal spores within at least a portion of said pores, at least partially coated with a protective coating; Self-healing materials, including:

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