Provided herein are methods and compositions utilizing one or more cementitious replacement materials, one or more alkaline activating materials, and, optionally one or more bonding materials and/or one or more setting time enhancer materials. The one or more cement precursors comprises one or more of calcareous sludge; paper pulp, biomass flyash; bag house dust; biomass sludge; filter cakes from bio industry's and wastewater treatment; bio ash; biomedical ash; agricultural ash; sugar cane bagasse; rice husk ash; palm oil fuel ash; oxygen furnace slags; plant stalks; bio char; starch; pyrophyllite; or a combination thereof. The one or more alkaline activating agents comprises potassium silicate, potassium hydroxide, sodium hydroxide, sodium silicate, calcium hydroxide, magnesium hydroxide, reactive magnesium oxide, calcium chloride, sodium carbonate, silicone dioxide, sodium aluminate, calcium sulfate, sodium sulfate, or dolomite, or a combination thereof. The system comprises a vertical impact mixer.

Class C fly ash-based cementitious materials, concretes, and related techniques are disclosed. In accordance with some embodiments, an activated class C fly ash-based cementitious material may be produced by intergrinding class C fly ash (e.g., classified to remove quartz and/or other contaminants and, thus, increase the reactive materials present), an activator, sodium citrate, borax, and a polycarboxylate material. The class C fly ash may have an amorphous glass content of about 60 wt % or more, a calcium oxide (CaO.sub.2) content of about 20 wt % or more, and a quartz content of about 10 wt % or less. The activator may be a chemical which reacts with class C fly ash to form str?tlingite structures therein when introduced with water. In some cases, the cementitious material may be provided as an all-in-one powder blend. In some cases, techniques disclosed herein may be utilized in providing a fast-setting flowable fill material.

A cement paste composition includes a curable component including a cementitious material and a zeolitic imidazolate framework-67 (ZIF-67) present in an amount of 0.01 to 3% by weight based on a total weight of the cementitious material. The composition further includes water in an amount of 30 to 50% by weight based on a total weight of the cement paste composition. A cured specimen made from the cement paste composition has a compressive strength of 30 to 80 megapascal (MPa) according to ASTM C109/C109M-21 standard test method, and a direct tensile strength of 1.2 to 2.2 MPa according to ASTM C307-18 standard test method. The ZIF-67 particles are uniformly distributed throughout the cured specimen. A method of producing the cement paste specimen.

In various embodiments, a process is described for the preparation of a concrete mixture in a Ready-mix or for an installation. A quantity of amorphous silica is added with an average particle size in the range of from about 1 to about 55 nanometers and/or wherein the surface area of the particles of the amorphous silica is in the range of from about 50 to about 900 m2/g. The amorphous silica may be added in colloidal form or otherwise, and is added at a particular stage to ensure efficacy.

The invention provides methods and compositions that prevent, mitigate or delay the onset of corrosion of iron or steel (e.g., plain carbon steel) components used as reinforcement or otherwise at least partially embedded in carbonated concrete composite materials and objects based on carbonatable calcium silicate cement.

Calcium silicate-based cements and concretes are disclosed, which result in concrete compositions that have an improved strength development. A cement product includes a plurality of particles of a carbonatable calcium silicate cement and a first additive; wherein, the first additive is an organic molecule with at least one primary, secondary or tertiary amine group.

A macro-cement and associated methods useful for preparing pastes, mortars, concretes and other cement-based materials having high workability, high density, and high strength are disclosed. A method of producing a macro-cement includes cement, supplemental cementitious materials (SCM's), including siliceous submicron-sized particles and nano-sized particles, and polymers in the form of liquid or dry chemical admixtures for concrete. The cement mixture may be used for making ultra-high performance concrete (UHPC).

Cementitious mixtures, compositions for use in cementitious mixtures, and methods of producing cementitious mixtures wherein the compositions are suitable for modifying or improving certain properties of the cementitious mixtures. The compositions include a superabsorbent polymer (SAP) hydrogel having a macromolecular network structure, and at least one pozzolanic material that is chemically incorporated into the macromolecular network structure of the SAP hydrogel.

A composition for backfilling a void. The composition may include between 40% and 65% air by volume, between 20% and 50% water by weight, between 5% and 50% calcium sulfoaluminate cement by weight, and between 20% and 55% filler by weight. The composition may have a compressive strength between 10 psi and 170 psi at four hours, a compressive strength between 20 psi and 310 psi at one day, and a compressive strength between 30 psi and 520 psi at twenty-eight days.

There is described a high-strength concrete generally having: about 100 parts by weight of cement; about 60 to about 360 parts by weight of fine aggregates; about 90 to about 230 parts by weight of mineral powder having a diameter D50 below 150 ?m; about 0.1 to about 25 parts by weight of superplasticizer; and about 20 to about 65 parts by weight of water, the high-strength concrete has a cement content less than about 500 kg/m.sup.3 and having a compressive strength after 28 curing days of about 55 MPa or greater.