The invention relates to fiber-containing concrete compositions containing hydraulically setting binders, fillers, one or more fibers, and possibly other additives or admixtures, characterized in that one or more vinylester-ethylene copolymers are contained as additional components.

The invention relates to fiber-containing concrete compositions containing hydraulically setting binders, fillers, one or more fibers, and possibly other additives or admixtures, characterized in that one or more vinylester-ethylene copolymers are contained as additional components.

A lost circulation material (LCM) is provided having an alkaline nanosilica dispersion and an ester activator. The alkaline nanosilica dispersion and the ester activator may form a gelled solid after interaction over a contact period. Methods of lost circulation control using the LCM are also provided.

A lost circulation material (LCM) is provided having an alkaline nanosilica dispersion and an ester activator. The alkaline nanosilica dispersion and the ester activator may form a gelled solid after interaction over a contact period. Methods of lost circulation control using the LCM are also provided.

A lost circulation material (LCM) is provided having an alkaline nanosilica dispersion and a polyester activator. The alkaline nanosilica dispersion and the polyester activator may form a gelled solid after interaction over a contact period. Methods of lost circulation control using the LCM are also provided.

A lost circulation material (LCM) is provided having an alkaline nanosilica dispersion and a polyester activator. The alkaline nanosilica dispersion and the polyester activator may form a gelled solid after interaction over a contact period. Methods of lost circulation control using the LCM are also provided.

A method of forming a cement composition. The method comprises adding to a hydraulic cementitious material a first strength-enhancing agent and a second strength-enhancing agent, wherein the content of total alkali (Na.sub.2O equivalent) in the hydraulic cementitious material is less than or equal to 0.7% by weight of the cementitious material. The first strength-enhancing agent includes a compound represented by structural formula (I):

##STR00001##

and
the second strength-enhancing agent is sodium sulfate, potassium sulfate, or a mixture thereof. The example values of the variables in structural formula (I) and the example amounts of the first and second strength-enhancing agents being added are defined herein.

Composite material, where the matrix material and the additive are held together by covalently or non-covalently bound ligands. The linker unit between matrix and additive has the structure Ligand1-LinkerL-Ligand 2, wherein Ligand1 and Ligand2 are a bond or a chemical entity that is capable of binding covalently or non-covalently to a structural entity, such as a polymer matrix or the additive (ex. CNT, graphene, carbon nanofiber, etc), and LinkerL is a chemical bond or entity that links Ligand1 and Ligand2.

A fiber reinforced concrete composition which cures to a cured fiber reinforced concrete composite following addition of water, the cured fiber reinforced concrete composite having a density from about 700 to 1000 kg/m.sup.3 and a compressive strength from about 5 to 15 MPa. A fiber reinforced concrete composition includes a brittle inorganic matrix precursor, a plurality of reinforcing fibers present in a range from 0.5 volume percent to less than 4 volume percent based on the total volume of the cured fiber reinforced concrete composite, and lightweight aggregate having a mean particle size in the range of 10 m to 1000 m, in an amount effective to achieve a target density in the cured composite not more than 1000 kg/m.sup.3. The reinforcing fibers include polypropylene fibers. The lightweight aggregate can include hollow fly ash spheres and glass microspheres. An acrylic admixture can be added to the composition.

A fiber reinforced concrete composition which cures to a cured fiber reinforced concrete composite following addition of water, the cured fiber reinforced concrete composite having a density from about 700 to 1000 kg/m.sup.3 and a compressive strength from about 5 to 15 MPa. A fiber reinforced concrete composition includes a brittle inorganic matrix precursor, a plurality of reinforcing fibers present in a range from 0.5 volume percent to less than 4 volume percent based on the total volume of the cured fiber reinforced concrete composite, and lightweight aggregate having a mean particle size in the range of 10 m to 1000 m, in an amount effective to achieve a target density in the cured composite not more than 1000 kg/m.sup.3. The reinforcing fibers include polypropylene fibers. The lightweight aggregate can include hollow fly ash spheres and glass microspheres. An acrylic admixture can be added to the composition.