A composition of a cement additive material to improve durability of cementitious structures, was disclosed. The cement additive composition includes an admixture of one or more of divalent magnesium metal silicates with capacity to act as a latent hydraulic binder in said composition activated by a hydration process under aqueous conditions, and in particular the divalent metal silicate is magnesium-dominated silicate, preferably comprising mineral groups of olivines, orthopyroxenes, amphiboles, and serpentines or mixtures thereof. The composition also includes chloride ions or brine.

Examples of novel self-repairing cement-polymer composites and processes of making and using are detailed that address various problems in prior art cements. These matrices, compositions and materials that are more mechanically robust, thermally stable and chemically resistant and demonstrate better bonding to various structures and materials, than other self-healing cements known in the prior art. When in place under preselected conditions (the formulation of the slurry can be modified for optimal effectiveness under various conditions) the organic, cross linking and cement forming portions within the slurry form interconnecting chemical bonds and cures to form a self-repairing and self-re-adhering cement polymer composite matrix in the receiving location.

Cement slurries, cured cements, and methods of making cured cement and methods of using cement slurries are provided. The cement slurries have, among other attributes, improved elasticity and self-healing properties and may be used, for instance, in the oil and gas drilling industry. The cement slurry comprises water, a cement precursor material, and a block copolymer composition. The block copolymer composition has at least one copolymer backbone, with each copolymer backbone comprising at least two hard segments. Furthermore, a soft segment is disposed between the at least two hard segments. The copolymer backbone has at least one anhydride group grafted onto the soft segment, and the anhydride group is crosslinked by an aminosilane crosslinker.

A railway tie being constructed of an engineered cementitious composite (ECC) material having: (1) a minimum of 2% tensile ductility of ECC, (2) complete absence of alkali-silica reaction (ASR), (3) high fatigue resistance of ECC at least five times that of normal concrete, (4) self-healing ability of ECC requiring only water and air, and (5) customization of ECC for lower stiffness in the tie (60% that of normal concrete) and higher abrasion resistance in the seat (three times that of normal concrete).

A composition of a cement additive material to improve durability of cementitious structures, was disclosed. The cement additive composition includes an admixture of one or more of divalent magnesium metal silicates with capacity to act as a latent hydraulic binder in said composition activated by a hydration process under aqueous conditions, and in particular the divalent metal silicate is magnesium-dominated silicate, preferably comprising mineral groups of olivines, orthopyroxenes, amphiboles, talc and serpentines or mixtures thereof. The composition also includes chloride ions or brine. Applications of the compositions are also disclosed, in particular to utilize a property of hydration as a major trigger for the latent hydraulic reaction of magnesium silicates, particularly for said olivines, when exposed to water and brines, in order to obtain a cementitious material becoming self healing.

A composition of matter has cement particles and resin structures having: a first functional group bonded directly to a surface of each cement particle; and a second functional group that bonds to calcium silicate hydrate upon hydration, wherein the second functional group is bondable with second functional groups of others of the cement particles to form a polymer network; and a backbone that connects the first functional group with the second functional group. A method of forming cement particles includes mixing cement particles with reactive molecules, the reactive molecules having a first functional group bonded directly to a surface of each cement particle, a second functional group that is bondable to calcium silicate hydrate upon hydration, wherein the second functional group is bondable with second function groups of others of the cement particles to form a polymer network, and a backbone that connects the first functional group with the second functional group. A composition of matter has cement particles, and a cured resin structure resulting from a reaction between two or more reactive molecules having functional groups that react with each other onto the surfaces of the cement particle, wherein one of the reactive molecules is used in less than a stoichiometric amount, leaving unreacted functional groups, and wherein the unreacted functional groups are bondable to calcium silicate hydrate upon hydration.

A composition comprising thermoset polymer, shape memory polymer to facilitate macro scale damage closure, and a means for molecular scale healing is disclosed; the composition has the ability to resolve structural defects by a bio-mimetic close-then heal process. In use, the shape memory polymer serves to bring surfaces of a structural defect into approximation, whereafter use of the means for molecular scale healing allowed for movement of the healing means into the defect and thus obtain molecular scale healing. The means for molecular scale healing can be a thermoplastic such as fibers, particles or spheres which are used by heating to a level at or above the thermoplastic's melting point, then cooling of the composition below the melting temperature of the thermoplastic. Compositions of the invention have the ability to not only close macroscopic defects, but also to do so repeatedly even if another wound/damage occurs in a previously healed/repaired area.

A composition comprising thermoset polymer, shape memory polymer to facilitate macro scale damage closure, and a means for molecular scale healing is disclosed; the composition has the ability to resolve structural defects by a bio-mimetic close-then heal process. In use, the shape memory polymer serves to bring surfaces of a structural defect into approximation, whereafter use of the means for molecular scale healing allowed for movement of the healing means into the defect and thus obtain molecular scale healing. The means for molecular scale healing can be a thermoplastic such as fibers, particles or spheres which are used by heating to a level at or above the thermoplastic's melting point, then cooling of the composition below the melting temperature of the thermoplastic. Compositions of the invention have the ability to not only close macroscopic defects, but also to do so repeatedly even if another wound/damage occurs in a previously healed/repaired area.

Provided is an amphoteric composite hydrogel, including: a polymer having a structure of formula I,

##STR00001##

wherein m, n, p and q are each an integer of 0 to 1000, m+n>100, p+q>100, R is

##STR00002##

R.sub.1 is H or an alkali metal element, and R.sub.2 is H or CH.sub.3; and a pozzolanic material incorporated into the structure of formula 1. Also provided are a cement mortar composition and a concrete composition each comprising the amphoteric composite hydrogel and a method of preparing the amphoteric composite hydrogel.

Provided is an amphoteric composite hydrogel, including: a polymer having a structure of formula I,

##STR00001##

wherein m, n, p and q are each an integer of 0 to 1000, m+n>100, p+q>100, R is

##STR00002##

R.sub.1 is H or an alkali metal element, and R.sub.2 is H or CH.sub.3; and a pozzolanic material incorporated into the structure of formula 1. Also provided are a cement mortar composition and a concrete composition each comprising the amphoteric composite hydrogel and a method of preparing the amphoteric composite hydrogel.