Abstract: A repaired reinforced concrete structure is provided which includes one or more reinforcing steel bars of cross-sectional area Ax, the one or more reinforcing steel bars having one or more corroded sections of cross-sectional area Ay, wherein Ay is greater than or equal to approximately 0.6 Ax. A reinforced ordinary Portland cement-based repair mortar is positioned directly on the one or more corroded sections of the one or more reinforcing steel bars without the addition of a lapped reinforcing steel bar. The reinforced repair mortar includes at least approximately 1 percent by volume of reinforcing steel fibers such that the reinforced repair mortar restores a strength of a repaired region to greater than approximately 100% of an original strength of the concrete structure in an uncorroded state. The repaired reinforced concrete structure is highly durable, as the repair mortar exhibits an air permeability resistance of greater than 1000 seconds.

Abstract: The present application provides for water capsules, preparation methods of water capsules, a preparation method for lightweight concrete and a structure of lightweight concrete. Each of the water capsules comprises an alkali-sensitive shell and water inside; the water capsules are used to mix with a cementitious matrix, the water capsules can survive during concrete mixing and transportation processes but then gradually rupture in hardened concrete; the water released during the hardening of the concrete is beneficial for the hydration of the concrete. The water capsules and their preparation method, the preparation method for and structure of the lightweight concrete of the present application are of unique design and strong practicability.

Abstract: A polymer-modified hybrid-fibers cementitious composition has a one-day compressive strength of at least approximately 17 MPa, a 28-day tensile strength of at least approximately 3.8 MPa, an ultimate tensile strain of approximately 3% to approximately 9%, and a 7-day bond strength of at least approximately 2.3 MPa. A binder of ordinary Portland cement, fly ash, and silica fume is provided. Other components include limestone powder, sand, superplasticizer, and water. The composition further includes one or more of styrene butadiene rubber or ethylene-vinyl acetate copolymer in an amount ranging between approximately 2% and approximately 8% by mass of binder. Fiber additives include steel fibers in an amount ranging between approximately 0.3% and approximately 3.0% by volume of the cementitious composition and polymer fibers in an amount less than approximately 1.0% by volume of the cementitious composition. Chamfers made of the composition are positioned at beam-column joints.

Abstract: A polymer-modified hybrid-fibers cementitious composition has a one-day compressive strength of at least approximately 17 MPa, a 28-day tensile strength of at least approximately 3.8 MPa, an ultimate tensile strain of approximately 3% to approximately 9%, and a 7-day bond strength of at least approximately 2.3 MPa. A binder of ordinary Portland cement, fly ash, and silica fume is provided. Other components include limestone powder, sand, superplasticizer, and water. The composition further includes one or more of styrene butadiene rubber or ethylene-vinyl acetate copolymer in an amount ranging between approximately 2% and approximately 8% by mass of binder. Fiber additives include steel fibers in an amount ranging between approximately 0.3% and approximately 3.0% by volume of the cementitious composition and polymer fibers in an amount less than approximately 1.0% by volume of the cementitious composition. Chamfers made of the composition are positioned at beam-column joints.

Abstract: A repaired reinforced concrete structure is provided which includes one or more reinforcing steel bars of cross-sectional area Ax, the one or more reinforcing steel bars having one or more corroded sections of cross-sectional area Ay, wherein Ay is greater than or equal to approximately 0.6 Ax. A reinforced ordinary Portland cement-based repair mortar is positioned directly on the one or more corroded sections of the one or more reinforcing steel bars without the addition of a lapped reinforcing steel bar. The reinforced repair mortar includes at least approximately 1 percent by volume of reinforcing steel fibers such that the reinforced repair mortar restores a strength of a repaired region to greater than approximately 100% of an original strength of the concrete structure in an uncorroded state. The repaired reinforced concrete structure is highly durable, as the repair mortar exhibits an air permeability resistance of greater than 1000 seconds.

Abstract: The present application provides for water capsules, preparation methods of water capsules, a preparation method for lightweight concrete and a structure of lightweight concrete. Each of the water capsules comprises an alkali-sensitive shell and water inside; the water capsules are used to mix with a cementitious matrix, the water capsules can survive during concrete mixing and transportation processes but then gradually rupture in hardened concrete; the water released during the hardening of the concrete is beneficial for the hydration of the concrete. The water capsules and their preparation method, the preparation method for and structure of the lightweight concrete of the present application are of unique design and strong practicability.

Abstract: This disclosure provides an eco-friendly multi-layer fabric reinforced cementitious matrix (FRCM) enhanced by nanoparticles. The FRCM is developed for structural strengthening and/or repairing in reinforced concrete buildings. The FRCM consists of multi-layer fabrics as load-carrying and crack control components and a cementitious matrix as bedding for the fabric layers. The cementitious matrix is eco-friendly based on a main constituent of ground granulated blast-furnace slag (GGBS) and recycled glass cullets. Some additions, including nanoparticles, superplasticizer, hydroxy propyl methyl cellulose and/or starch ether, are added to achieve proper workability and rheology for application requirements, and to enhance fresh properties, mechanical properties and/or durability. Man-made fabric and natural fabric are embedded in the cementitious matrix with designated purposes of load carrying and crack control.