A cementitious blend composition and a concrete mix composition preferable for making concrete resistant to high temperatures and alkaline conditions, particularly for making durable concrete for constructing an alumina digester tank in an aluminum smelter. The cementitious blend composition includes at least one hydraulic cement, silica fume (SF), and natural pozzolan (NP), wherein a weight percent ratio of at least one hydraulic cement:SF:NP in the cementitious blend composition lies in the range of (24-63):(5-44):(32-40) with the sum of the weight percentages of the at least one hydraulic cement, the SF, and the NP not exceeding 100%. The concrete mix composition comprises water and the cementitious blend composition, wherein a weight ratio of the water to the cementitious blend composition is 0.2-0.5, and wherein the concrete mix composition has a content of the cementitious blend composition of 400-550 kg/m.sup.3.

A cementitious blend composition and a concrete mix composition preferable for making concrete resistant to high temperatures and alkaline conditions, particularly for making durable concrete for constructing an alumina digester tank in an aluminum smelter. The cementitious blend composition includes at least one hydraulic cement, silica fume (SF), and natural pozzolan (NP), wherein a weight percent ratio of at least one hydraulic cement:SF:NP in the cementitious blend composition lies in the range of (24-63):(5-44):(32-40) with the sum of the weight percentages of the at least one hydraulic cement, the SF, and the NP not exceeding 100%. The concrete mix composition comprises water and the cementitious blend composition, wherein a weight ratio of the water to the cementitious blend composition is 0.2-0.5, and wherein the concrete mix composition has a content of the cementitious blend composition of 400-550 kg/m.sup.3.

A method for controlling the volume expansion of a hydraulically setting composition including steel making slag, the method including a step of adding a silica source to the composition. Furthermore, hydraulically setting compositions obtained by such methods and their uses.

A method for controlling the volume expansion of a hydraulically setting composition including steel making slag, the method including a step of adding a silica source to the composition. Furthermore, hydraulically setting compositions obtained by such methods and their uses.

A tubing string may include a swellable metal material for providing a seal downhole. The swellable metal material may react with a silica material and a water-based fluid to cause the swellable metal material to swell and form a seal within a flow path defined in part by the tubing string.

A tubing string may include a swellable metal material for providing a seal downhole. The swellable metal material may react with a silica material and a water-based fluid to cause the swellable metal material to swell and form a seal within a flow path defined in part by the tubing string.

A composite including a polymeric material or emulsion and biochar. The composite includes 1 wt % to 20 wt % of the biochar. Making the composite includes combining biochar with a polymeric material or emulsion to yield a modified polymeric material or emulsion, and homogenizing the modified polymeric material or emulsion to yield the composite. Functionalizing biochar includes removing contaminants from the biochar to yield decontaminated biochar, oxidizing the decontaminated biochar to yield oxidized biochar, and functionalizing the oxidized biochar. Making nitrogen-doped biochar includes combining urea and wood residue to form a mixture, and heating the mixture in an oxygen-free environment to form the nitrogen-doped biochar.

A composite including a polymeric material or emulsion and biochar. The composite includes 1 wt % to 20 wt % of the biochar. Making the composite includes combining biochar with a polymeric material or emulsion to yield a modified polymeric material or emulsion, and homogenizing the modified polymeric material or emulsion to yield the composite. Functionalizing biochar includes removing contaminants from the biochar to yield decontaminated biochar, oxidizing the decontaminated biochar to yield oxidized biochar, and functionalizing the oxidized biochar. Making nitrogen-doped biochar includes combining urea and wood residue to form a mixture, and heating the mixture in an oxygen-free environment to form the nitrogen-doped biochar.

A method for reducing lost circulation in a subterranean formation. The method includes providing a treatment fluid comprising a base fluid and a lost circulation material comprising cane ash. The treatment fluid is introduced into a wellbore within the subterranean formation such that at least a portion of the cane ash bridges openings in the subterranean formation to reduce loss of fluid circulation into the subterranean formation.

A method for reducing lost circulation in a subterranean formation. The method includes providing a treatment fluid comprising a base fluid and a lost circulation material comprising cane ash. The treatment fluid is introduced into a wellbore within the subterranean formation such that at least a portion of the cane ash bridges openings in the subterranean formation to reduce loss of fluid circulation into the subterranean formation.