Acid-resistant composite materials and methods of forming acid resistant composite materials are disclosed. The acid resistant composite materials can include one or more monovalent, divalent, or polyvalent cationic metals. The acid resistant composite materials can be used, for example, in the formation of concreate or as a coating for concrete.

Methods of preparing engineered cementitious composite precursors include carbonating a fly ash comprising >about 25% by weight of calcium oxide (CaO) and having a water content of >about 12% to <about 18% by weight of water by exposing the fly ash to a first gas stream comprising carbon dioxide to form a carbonated fly ash. A steel slag is also carbonated that comprises>about 40% by weight of calcium oxide (CaO) and having a water content of >about 12% to <about 18% by weight of water by exposing the steel slag to a second gas stream comprising carbon dioxide to form a carbonated steel slag. The carbonated fly ash and the carbonated steel slag are suitable for use as engineered cementitious composite precursors in a bendable engineered cementitious composite composition that further comprises Portland cement, a polymeric fiber, and a superplasticizer.

Disclosed is a magnesium-based cementitious material, preparation method and application thereof. The magnesium-based cementitious material, comprising magnesite, sandstone, and water, wherein: the magnesite is provided with CaO, SiO.sub.2, Al.sub.2O.sub.3, Fe.sub.2O.sub.3, and MgO, a mass percentage of the CaO is less than 5%, a mass percentage of SiO.sub.2 is less than 5%, a mass percentage of Al.sub.2O.sub.3 is less than 5%, a mass percentage of Fe.sub.2O.sub.3 is less than 7%, a mass percentage of MgO is between 37% and 50%; the sandstone is provided with SiO.sub.2, CaO, Al.sub.2O.sub.3, and Fe.sub.2O.sub.3, a mass percentage of SiO.sub.2 is greater than 70%. The beneficial effects of this disclosure are: the cementitious material does not contain MgCl.sub.2, which avoids the reduction of the strength of the cementitious material due to the dissolution of MgCl.sub.2 in water; the magnesium-based cementitious material of this disclosure is immiscible with water and has strong water resistance.

The invention relates to a mineral binder suitable for use in binding aggregate in a mineral mortar or concrete mixture, said binder comprising the following components:

a) at least 40 wt % of calcined kaolinitic clay and ultrafine crushed CDW,
wherein the ratio between calcined clay and ultrafine crushed CDW is between 3:7 and 1:1 (w/w),
b) optionally 2-50 wt. % of a chemical activator; and
wherein the calcined kaolinitic clay, the ultrafine crushed CDW and the optionally present chemical activator are present in a combined amount of at least 90 wt. %, based on the total weight of the binder. The invention further relates to mineral mortar or concrete mixtures based on this mineral binder, as well as building units made from these mixtures.

A method of reducing lost circulation includes introducing a lost circulation solution comprising Saudi Arabian volcanic ash, a curing agent, and a resin into a subsurface formation through a wellbore, wherein the Saudi Arabian volcanic ash comprises SO.sub.3, CaO, SiO.sub.2, Al.sub.2O.sub.3, Fe.sub.2O.sub.3, MgO, and K.sub.2O; and allowing the lost circulation solution to thicken within the subsurface formation, thereby forming a barrier between the subsurface formation and the wellbore to reduce lost circulation.

An insulating material, in particular a permeable fire-proof insulating material comprising water glass and polystyrene, consisting of a hardening mixture which contains 1 to 32.4 wt % of expanded polystyrene, 57.5 to 96.0 wt % of aqueous sodium silicate solution, 2 to 6 wt % of aluminium hydroxide, 0.8 to 2.6 wt % water glass hardener and 0.1 to 0.5 wt % of water glass stabilizer, while the surface of the expanded polystyrene is provided with carbon black, the carbon black making up 0.1 to 1 wt % of total weight. A method for the production of insulating material, in particular a method for the production of permeable fire-proof insulating material comprising water glass and polystyrene, according to which firstly the polystyrene beads are mixed with an aqueous solution of carbon black so as to coat their entire surface, then is added to the aqueous sodium silicate solution aluminium hydroxide and the whole is mixed so as to form an insulating mixture, and then a water glass stabilizer is added to the aqueous sodium silicate solution, and then to this solution is mixed water glass hardener, with this solution being further stirred for 1 to 10 minutes to form a binder solution, and the insulating mixture is added to the binder solution with constant stirring, and the whole is mixed, and the resulting mixture is then poured into the application site.

A lime-based cement extender composition, and associated systems and methods are disclosed herein. In some embodiments, the lime-based cement extender composition includes 5-20% by weight lime particles, 40-50% by weight limestone particles, and 40-50% by weight pozzolan particles. Additionally or alternatively, the lime-based cement extender composition can comprise a calcium oxide concentration of 45-65%, a magnesium oxide concentration of 0.5-2%, an iron oxide concentration of 0.5-2.0%, an aluminum oxide concentration of 2-8%, a silicon dioxide concentration of 20-40%, a potassium oxide concentration of 20,000-30,000 ppm, and a sodium oxide concentration of 10,000-20,000 ppm. In some embodiments, the lime-based cement extender composition, or product, is combined with cement to produce a cement blend for use in the mining industry as mine backfill.

A geopolymeric ink formulation for direct 3D printing containing a geopolymeric formulation whose components are present in such proportions as to be subjected to a geopolymerization reaction and to provide, at the end of the reaction, a solid geopolymer and wherein the formulation, before and during at least a part of the geopolymerization reaction, wherein three-dimensional chemical bonds have not yet been formed, forms a reversible-gel, non-Newtonian, viscoelastic fluid. The formulation is extruded through a 3D printing tool equipped with nozzle into strands according to a geometry such as to create a three-dimensional structure on one or more layers. The extrusion preferably takes place within a hydrophobic liquid, such as oil.

Disclosed is a magnesium-based cementitious material, preparation method and application thereof. The magnesium-based cementitious material, comprising magnesite, sandstone, and water, wherein: the magnesite is provided with CaO, SiO.sub.2, Al.sub.2O.sub.3, Fe.sub.2 O.sub.3, and MgO, a mass percentage of the CaO is less than 5%, a mass percentage of SiO.sub.2 is less than 5%, a mass percentage of Al.sub.2 O.sub.3 is less than 5%, a mass percentage of Fe.sub.2 O.sub.3 is less than 7%, a mass percentage of MgO is between 37% and 50%; the sandstone is provided with SiO.sub.2, CaO, Al.sub.2 O.sub.3, and Fe.sub.2O.sub.3, a mass percentage of SiO.sub.2 is greater than 70%. The beneficial effects of this disclosure are: the cementitious material does not contain MgCl.sub.2, which avoids the reduction of the strength of the cementitious material due to the dissolution of MgCl.sub.2 in water; the magnesium-based cementitious material of this disclosure is immiscible with water and has strong water resistance.

Portland cement compositions for use in high-temperature, high pressure wells are designed such that the lime-to-silica molar ratio is between 0.5 and 1.0, and the alumina-to-silica molar ratio is between 0.05 and 0.10. After curing and setting at temperatures between 85° C. and 300° C., the cement compositions form tobermorite as an initial and permanent calcium silicate hydrate phase.