In the present disclosure, a cement board is disclosed. The cement board comprises a core having a first surface and a second surface opposite the first surface and a binder including a pozzolan material and a water-resistant additive, wherein the water-resistant additive is present in an amount of less than 5 wt. % based on the weight of the pozzolan material.

A method for producing a composite insulating mineral construction element includes filling the cavity of a construction element including at least one cavity delimited by at least one inner wall at least partially having a water absorption rate of more than 5 g/(m.sup.2.Math.s) at 10 minutes according to standard NF EN 772-11 of August 2011 with a foamed cement slurry including a cement being an hydraulic binder including a proportion of at least 50% by weight of calcium oxide CaO and silicone dioxide SiO.sub.2, a metal salt selected from an aluminium, magnesium or iron salt and mixtures thereof, and a cellulose ether; and leaving the foamed cement slurry to set within the cavity resulting in the formation of a mineral foam, wherein the foamed cement slurry includes from 0.01 to 0.2% by weight of cellulose ether, relative to the weight of cement.

A method for producing a composite insulating mineral construction element includes filling the cavity of a construction element including at least one cavity delimited by at least one inner wall at least partially having a water absorption rate of more than 5 g/(m.sup.2.Math.s) at 10 minutes according to standard NF EN 772-11 of August 2011 with a foamed cement slurry including a cement being an hydraulic binder including a proportion of at least 50% by weight of calcium oxide CaO and silicone dioxide SiO.sub.2, a metal salt selected from an aluminium, magnesium or iron salt and mixtures thereof, and a cellulose ether; and leaving the foamed cement slurry to set within the cavity resulting in the formation of a mineral foam, wherein the foamed cement slurry includes from 0.01 to 0.2% by weight of cellulose ether, relative to the weight of cement.

Composite cellulosic products and processes for making same. In some embodiments, the composite cellulosic product can include a plurality of cellulosic substrates and an at least partially cured binder. Prior to curing, the binder can include a mixture formed by combining magnesium oxide, water, and magnesium chloride. A weight ratio of the magnesium oxide to the magnesium chloride in the binder can be at least 2.2:1 to 8.5:1.

Composite cellulosic products and processes for making same. In some embodiments, the composite cellulosic product can include a plurality of cellulosic substrates and an at least partially cured binder. Prior to curing, the binder can include a mixture formed by combining magnesium oxide, water, and magnesium chloride. A weight ratio of the magnesium oxide to the magnesium chloride in the binder can be at least 2.2:1 to 8.5:1.

A retarder mixture for oil and gas well cementing includes a lignosulfonate compound and at least one hydrolyzed carbohydrate. A method includes blending the retarder mixture and a cement precursor to form a cement precursor mixture and introducing water into the cement precursor mixture to form a cement mixture. The cement mixture is pumped down a well and cures to form a cement sheath containing the cement precursor and the retarder mixture.

A retarder mixture for oil and gas well cementing includes a lignosulfonate compound and at least one hydrolyzed carbohydrate. A method includes blending the retarder mixture and a cement precursor to form a cement precursor mixture and introducing water into the cement precursor mixture to form a cement mixture. The cement mixture is pumped down a well and cures to form a cement sheath containing the cement precursor and the retarder mixture.

A retarder mixture for oil and gas well cementing includes a lignosulfonate compound and at least one hydrolyzed carbohydrate. A method includes blending the retarder mixture and a cement precursor to form a cement precursor mixture and introducing water into the cement precursor mixture to form a cement mixture. The cement mixture is pumped down a well and cures to form a cement sheath containing the cement precursor and the retarder mixture.

Disclosed are a fireproof material, a fireproof plate, a fireproof wall structure for tunnels and a construction method. The fireproof material includes the following components in weight ratio: 20-35 parts of aluminosilicate; 10-25 parts of calcium carbonate; 5-15 parts of magnesium oxide; 5-15 parts of silica; 20-40 parts of a binder; and 5-10 parts of a curing agent, the binder includes at least one of lithium silicate, potassium silicate and sodium silicate in combination with at least one of quartz sand and industrial sugar; and the curing agent is at least one of lithium oxide and magnesium oxide. In the preparation, firstly forming the mixture of aluminosilicate, magnesium oxide and silica into particles at 900° C.-1250° C., and then mixing the particles with calcium carbonate, the binder and the curing agent, and then pouring same into a forming mold and heating and pressing to form the fireproof material.

Disclosed are a fireproof material, a fireproof plate, a fireproof wall structure for tunnels and a construction method. The fireproof material includes the following components in weight ratio: 20-35 parts of aluminosilicate; 10-25 parts of calcium carbonate; 5-15 parts of magnesium oxide; 5-15 parts of silica; 20-40 parts of a binder; and 5-10 parts of a curing agent, the binder includes at least one of lithium silicate, potassium silicate and sodium silicate in combination with at least one of quartz sand and industrial sugar; and the curing agent is at least one of lithium oxide and magnesium oxide. In the preparation, firstly forming the mixture of aluminosilicate, magnesium oxide and silica into particles at 900° C.-1250° C., and then mixing the particles with calcium carbonate, the binder and the curing agent, and then pouring same into a forming mold and heating and pressing to form the fireproof material.