Disclosed are a crack self-healing agent for cement-based materials capable of binding corrosive ions in seawater, and a preparation method thereof. A core material of the agent is an active inorganic composite component capable of chemically binding Cl, Mg, and S, a wall layer is polymethyl methacrylate, and an interface improvement layer is a cement layer. A preparation method includes: (1) thoroughly mixing active components capable of binding corrosive ions, and filling a resulting mixture into a direct compression mold; (2) applying a pressure to the direct compression mold and holding the pressure on using a pressing machine, and demolding to obtain a core material body; (3) placing the core material body obtained in a solution of PMMA in acetone for coating, and taking out the core material body and drying; (4) coating a layer of cement before the acetone is completely volatilized to obtain the crack self-healing agent.

The present invention provides a concrete vacuum tube segment for a hyper-speed transportation system using ultra-high performance concrete (UHPC) and a manufacturing method thereof. A concrete vacuum tube segment for a hyper-speed transportation system can be easily manufactured using UHPC, in which shrinkage and structural cracking do not occur due to mixing a binder and a short fiber to secure airtightness on the basis of a maximum fill theory, and accordingly, shrinkage of the concrete vacuum tube segment can be reduced even in a partial-vacuum state in which the magnitude of drying shrinkage is very small and quick drying occurs; when mixing the UHPC, an antifoaming agent is mixed and a circular vacuum pump is used to remove generated entrapped air to minimize the entrapped air; and a capsule-type crack healing material, which is able to repair fine cracks, is compacted to secure airtightness of the concrete vacuum tube segment.

The present invention provides a concrete vacuum tube segment for a hyper-speed transportation system using ultra-high performance concrete (UHPC) and a manufacturing method thereof. A concrete vacuum tube segment for a hyper-speed transportation system can be easily manufactured using UHPC, in which shrinkage and structural cracking do not occur due to mixing a binder and a short fiber to secure airtightness on the basis of a maximum fill theory, and accordingly, shrinkage of the concrete vacuum tube segment can be reduced even in a partial-vacuum state in which the magnitude of drying shrinkage is very small and quick drying occurs; when mixing the UHPC, an antifoaming agent is mixed and a circular vacuum pump is used to remove generated entrapped air to minimize the entrapped air; and a capsule-type crack healing material, which is able to repair fine cracks, is compacted to secure airtightness of the concrete vacuum tube segment.

A cementitious composition including recycled superabsorbent polymer (RSAP) and a cementitious material. The RSAP has a purity level of at least 85 percent by weight of the RSAP. Also provided is a cementitious composition where the RSAP has substantially low levels of one or more residual drug entities. Also provided is a method for the construction of a self-sealing cement sheath, the method comprising: supplying a self-sealing slurry of a cementitious composition including cementitious material, an aqueous fluid, and RSAP into an underground geological formation, and allowing the self-sealing slurry of the cementitious composition to cure, thereby forming the self-sealing cement sheath. The RSAP is capable of swelling in the presence of fluid to seal any cracks formed in the self-sealing slurry during curing.

Provided is a method for altering properties of tension programmed fibrous shape memory polymer. The method can include applying a protective coating to the tension programmed shape memory polymer, then applying a supportive coating to the tension programmed shape memory polymer to form a coated fiber. The protective coating avoids contact between the shape memory polymer and chemicals used in the supportive coating that can decompensate the shape memory polymer.

Provided is a method for altering properties of tension programmed fibrous shape memory polymer. The method can include applying a protective coating to the tension programmed shape memory polymer, then applying a supportive coating to the tension programmed shape memory polymer to form a coated fiber. The protective coating avoids contact between the shape memory polymer and chemicals used in the supportive coating that can decompensate the shape memory polymer.

The invention discloses an environment-friendly cement self-repairing system, and its preparation method and application. The preparation method comprises the following steps: adding a shell curing agent into deionized water to prepare solution 1, adding an inorganic nano emulsifier into deionized water, ultrasonically dispersing, then adding polysaccharide-shell, and uniformly stirring to obtain emulsion polymerization aqueous phase; adding epoxy diluent into epoxy resin, and uniformly stirring; obtaining an emulsion polymerization oil phase; mixing the emulsion polymerization aqueous phase and emulsion polymerization oil phase, and stirring to obtain uniform emulsion; dropping the uniform emulsion into solution drop by drop by using pendant drop method, stirring until the droplets are shaped, then filtering, washing with deionized water, and drying to obtain self-repairing capsules; next, mixing with an environment-friendly curing agent to obtain an environment-friendly cement self-repairing system. The environment-friendly cement self-repairing system is green, nontoxic and harmless, has strong water absorption, can block tiny cracks by volume expansion when contacts with water, thus further enhances the cement self-repairing effect.

The present invention provides a concrete vacuum tube segment for a hyper-speed transportation system using ultra-high performance concrete (UHPC) and a manufacturing method thereof. A concrete vacuum tube segment for a hyper-speed transportation system can be easily manufactured using UHPC, in which shrinkage and structural cracking do not occur due to mixing a binder and a short fiber to secure airtightness on the basis of a maximum fill theory, and accordingly, shrinkage of the concrete vacuum tube segment can be reduced even in a partial-vacuum state in which the magnitude of drying shrinkage is very small and quick drying occurs; when mixing the UHPC, an antifoaming agent is mixed and a circular vacuum pump is used to remove generated entrapped air to minimize the entrapped air; and a capsule-type crack healing material, which is able to repair fine cracks, is compacted to secure airtightness of the concrete vacuum tube segment.

The present invention provides a concrete vacuum tube segment for a hyper-speed transportation system using ultra-high performance concrete (UHPC) and a manufacturing method thereof. A concrete vacuum tube segment for a hyper-speed transportation system can be easily manufactured using UHPC, in which shrinkage and structural cracking do not occur due to mixing a binder and a short fiber to secure airtightness on the basis of a maximum fill theory, and accordingly, shrinkage of the concrete vacuum tube segment can be reduced even in a partial-vacuum state in which the magnitude of drying shrinkage is very small and quick drying occurs; when mixing the UHPC, an antifoaming agent is mixed and a circular vacuum pump is used to remove generated entrapped air to minimize the entrapped air; and a capsule-type crack healing material, which is able to repair fine cracks, is compacted to secure airtightness of the concrete vacuum tube segment.

The invention discloses an environment-friendly cement self-repairing system, and its preparation method and application. The preparation method comprises the following steps: adding a shell curing agent into deionized water to prepare solution 1, adding an inorganic nano emulsifier into deionized water, ultrasonically dispersing, then adding polysaccharide-shell, and uniformly stirring to obtain emulsion polymerization aqueous phase; adding epoxy diluent into epoxy resin, and uniformly stirring; obtaining an emulsion polymerization oil phase; mixing the emulsion polymerization aqueous phase and emulsion polymerization oil phase, and stirring to obtain uniform emulsion; dropping the uniform emulsion into solution drop by drop by using pendant drop method, stirring until the droplets are shaped, then filtering, washing with deionized water, and drying to obtain self-repairing capsules; next, mixing with an environment-friendly curing agent to obtain an environment-friendly cement self-repairing system. The environment-friendly cement self-repairing system is green, nontoxic and harmless, has strong water absorption, can block tiny cracks by volume expansion when contacts with water, thus further enhances the cement self-repairing effect.