A high-thermal conductivity grout composition is provided. The composition includes a grout mixture including a cementitious material, a retarder, and a high-thermal k material that advantageously can form a pumpable slurry upon admixture with water. The retarder is present in an amount effective that delays setting of the grout mixture at a target location having a geostatic target temperature of at least 300 F. for at least two hours. The high-thermal k material is present in an amount effective such that the grout mixture has, upon setting at the target location, a thermal conductivity of at least 1 W/m K.

A material composition for a bio-composite plaster material for use in construction is disclosed. The composition includes a binder, a filler, a polymer, and an additive. The binder includes calcium sulphate hemihydrate, the filler includes cork, the polymer includes vinyl acetate, and the additive includes modified amino acid. The filler is an agro-based bio fiber. The composition provides high thermal insulation. A method of preparing and using the composition includes preparing the composition, mixing the composition with water for a first predetermined amount of time to produce the bio-composite plaster material having a predetermined consistency, and applying a coat of the bio-composite plaster material on a surface during the construction activity.

A new class of multi-component rare earth multi-silicate materials has been created for use in harsh environments such as gas turbine engines. Moreover, by combining two-or-more rare earth disilicates the properties (for example, thermal expansion, thermal conductivity, etc.) can be tailored to fit specific applications, such as having a matching thermal expansion with that of silicon-based composites and a low thermal conductivity close to that of 1 W/m K. Applications can be extended for use with other material classes such as MCrAlY, MAX-phase, and refractory metal alloys, utilizing a thermal expansion of up to about 1510.sup.6/ C. By mixing of specific sets of rare earth disilicates it is possible to obtain a high entropy or entropy stabilized mixture, and utilize features such as sluggish diffusion, and more.

A method of cementing a geothermal wellbore includes pumping a first volume of cement slurry down a wellbore. The first volume of cement slurry has a first water to cement ratio. A second volume of cement slurry is pumped down the wellbore. The second volume of cement slurry has a second water to cement ratio that is less than the first water to cement ratio. The first volume of cement slurry hardens at a vertical portion of the wellbore, and the second volume of cement slurry hardens at a horizontal portion of the wellbore.

A method for preparing heat-conductive cement slurry for well cementation includes the following steps: S1, uniformly mixing sodium 1-butanesulfonate, sodium dodecyl diphenyl ether disulfonate and polyvinylpyrrolidone to obtain an admixture; S2, dissolving the admixture in deionized water and stirring to obtain a dispersant solution; S3, adding graphite to the dispersant solution and stirring to obtain a graphite dispersion; S4, stirring cement and deionized water in a slurry cup to obtain cement slurry; and S5, mixing and stirring the graphite dispersion and the cement slurry to obtain the heat-conductive cement slurry. The heat-conductive cement slurry can effectively improve the heat conductivity coefficient of set cement, and significantly improve the heat conductivity of the set cement, and has a broad market application prospect.

Concrete materials and thermal energy storage devices employing such concrete materials are disclosed herein. The concrete material may include fibers in an amount ranging from about 1 to about 2 vol. %; an aggregate in an amount ranging from about 50 to about 80 vol. %, wherein the aggregates comprises siliceous aggregate and optionally carbonate aggregate; and a cementitious material in an amount from about 12 to about 20 vol. %, wherein the cementitious material comprises a combination of about 70 to about 85 vol. % of Portland cement and about 15 to about vol. % of silica fume, wherein all volume percentages unless otherwise indicated are based on the total volume of the concrete material.

A high-thermal conductivity grout composition is provided. The composition includes a grout mixture including a cementitious material, a retarder, and a high-thermal k material that advantageously can form a pumpable slurry upon admixture with water. The retarder is present in an amount effective that delays setting of the grout mixture at a target location having a geostatic target temperature of at least 300 F. for at least two hours. The high-thermal k material is present in an amount effective such that the grout mixture has, upon setting at the target location, a thermal conductivity of at least 1 W/m K.

Compositions and methods for thermal reach enhancement (TRE) are presented in which a TRE material comprises at least two functionally distinct solid components that enable high thermal conductivity with minimal flowback during and after placement, even where the TRE is placed into a low permeability formation. The first component is characterized by low kinetic friction and deformability upon compression, the second component is characterized by high internal and external kinetic friction and interlocking upon compression, and the first and second components form a compacted hybrid high thermal k material with minimal void space.

Cementing compositions contain water, a cement and an additive for adjusting thermal conductivity. The additive for adjusting thermal conductivity may be graphite, graphene, aluminum oxide, hematite, copper metal, copper oxide, aluminum, amorphous carbon, gallium metal, iron metal, magnesium oxide, nickel metal, nickel oxide, tin metal, tin oxide, zinc metal or zinc oxide, or combinations thereof. Such compositions may have thermal conductivities exceeding 2 W/mK. Such compositions may be useful in closed loop geothermal completions or for encasing electrical cables.

Sub-ambient daytime radiative cooling (SDRC) coating comprising: an alkali activated metakaolin, BaSO.sub.4, and silica nanospheres, wherein the alkali activated metakaolin is prepared by reaction of metakaolin with an alkali activator comprising waterglass and a strong base selected from the group consisting of LiOH, NaOH, KOH, Ca(OH).sub.2, Li.sub.2O Na.sub.2O, K.sub.2O, CaO, and a mixture thereof, a coating formulation comprising the same, and a method of preparation and use thereof.