Processes are disclosed for producing gypsum-based products from a gypsum slurry. Additives or combinations of additives for improving compressive strength, fluidity and/or set time of the gypsum product are mixed in intimate contact with raw gypsum prior to or during grinding and/or flash calcination to form stucco. The stucco is used to prepare a gypsum slurry which is shaped and sets to form the gypsum product.

A method of cementing a wellbore penetrating a subterranean formation comprises injecting into the wellbore a settable slurry comprising: an aqueous carrier; an aggregate; urea; a calcium source; and a calcium carbonate producing agent comprising a microbe, an enzyme, or a combination comprising at least one of the foregoing; and allowing the slurry to set.

A method of cementing a wellbore penetrating a subterranean formation comprises injecting into the wellbore a settable slurry comprising: an aqueous carrier; an aggregate; urea; a calcium source; and a calcium carbonate producing agent comprising a microbe, an enzyme, or a combination comprising at least one of the foregoing; and allowing the slurry to set.

Compositions and methods are disclosed for sealing subterranean spaces such as natural or induced fractures, vugs or annular spaces. The composition is composed of a base fluid consisting of a soluble alkali silicate, a gas generating additive, water, solids, and a setting agent. The gas generating additive may be coated or uncoated. The gas generating additive may also be in the form of a slurry. In the case of coated additives, the coating may act as a retarder or an accelerator to the expansion and setting agent of the soluble alkali silica. Similarly, the choice of carrier fluid in a slurry may retard or accelerate the expansion and setting of the alkali silicate-based plug.

Compositions and methods are disclosed for sealing subterranean spaces such as natural or induced fractures, vugs or annular spaces. The composition is composed of a base fluid consisting of a soluble alkali silicate, a gas generating additive, water, solids, and a setting agent. The gas generating additive may be coated or uncoated. The gas generating additive may also be in the form of a slurry. In the case of coated additives, the coating may act as a retarder or an accelerator to the expansion and setting agent of the soluble alkali silica. Similarly, the choice of carrier fluid in a slurry may retard or accelerate the expansion and setting of the alkali silicate-based plug.

One aspect of the present invention is directed to a method of preparing encapsulated ureolytic cells. This method includes blending freeze dried ureolytic cells and an aqueous solution to form a base mixture; mixing the base mixture with a silicate-forming compound to form a blend comprising silica encapsulated ureolytic cells; and freeze drying the silica encapsulated ureolytic cells. The present invention also relates to a method of producing a self-healing concrete. This method comprises providing silica encapsulated freeze-dried ureolytic cells; mixing the silica encapsulated freeze-dried ureolytic cells with cement to form a mixture; and blending the mixture with a calcium salt and a urea solution to form a concrete mixture. Also disclosed are silica encapsulated ureolytic cells, a method of making a concrete form, and a cured concrete product.

One aspect of the present invention is directed to a method of preparing encapsulated ureolytic cells. This method includes blending freeze dried ureolytic cells and an aqueous solution to form a base mixture; mixing the base mixture with a silicate-forming compound to form a blend comprising silica encapsulated ureolytic cells; and freeze drying the silica encapsulated ureolytic cells. The present invention also relates to a method of producing a self-healing concrete. This method comprises providing silica encapsulated freeze-dried ureolytic cells; mixing the silica encapsulated freeze-dried ureolytic cells with cement to form a mixture; and blending the mixture with a calcium salt and a urea solution to form a concrete mixture. Also disclosed are silica encapsulated ureolytic cells, a method of making a concrete form, and a cured concrete product.

There is provided a method for producing construction material utilizing loose pieces of aggregate, enzyme producing bacteria, an amount of urea and an amount of calcium ions. A first solution is prepared which includes urease which is formed by enzyme producing bacteria. A second solution is prepared which includes urea and calcium ions. The first and second solutions are added to the loose aggregate. The calcium ions contribute to the formation of calcium carbonate wherein the calcium carbonate fills and bonds between at least some of the gaps between the loose pieces of aggregate forming a solid construction material.

There is provided a method for producing construction material utilizing loose pieces of aggregate, enzyme producing bacteria, an amount of urea and an amount of calcium ions. A first solution is prepared which includes urease which is formed by enzyme producing bacteria. A second solution is prepared which includes urea and calcium ions. The first and second solutions are added to the loose aggregate. The calcium ions contribute to the formation of calcium carbonate wherein the calcium carbonate fills and bonds between at least some of the gaps between the loose pieces of aggregate forming a solid construction material.

A temperature-sensitive anti-freezing material for asphalt pavement and a method for preparing same. A temperature-sensitive macro molecular organic matter is employed in the anti-freezing material instead of a traditional sustained release agent, and coated on the surface of the chloride particle having an anti-icing anti-freezing effect; and then the temperature-sensitive anti-freezing material for asphalt pavement is prepared by sieving and drying processes. The anti-freezing material can automatically respond to and control the release temperature of the chloride in the anti-freezing material according to the outside temperature, increase the anti-freezing effect duration of the chloride in the asphalt pavement effectively, and extend the service lifetime of the anti-freezing material.