A concrete composition and method include a portion of fine aggregate bearing a coating of a polymer or an admixture, which may be a continuous coating layer or a layer of powdered, discrete particles embedded in a binder. The polymeric coating may be an admixture in powdered form, a super absorbent polymer (insoluble in water, but absorbing water), or another polymer such as the acrylamides, co-polymers thereof, polyacrylamides, or the like (soluble in water). The coating absorbs water, but particles are too small to form significant voids. Water is absorbed into the concrete mix in far greater proportions (e.g. w/c ratio over 0.5) improving workability, doubling workability time, and improving ultimate compressive stress (strength).

Fibers to be added to concrete to improve its properties are coated with an alkali-insoluble polymer, to provide adhesion of the fibers to the concrete. In a further improvement, nanoparticles are dispersed in an alkali-soluble polymer coating, and this is used to coat the fibers. When the fibers are mixed into the concrete mix, the nanoparticles are dispersed throughout the concrete, avoiding problems from agglomeration of the nanoparticles if simply added to the concrete mix.

A gypsum panel includes a gypsum core containing a termiticide with poor water solubility, wherein the gypsum core has a first end region, a center region, and a second end region having an equal thickness and extending along a thickness direction from one surface side to another surface side, the termiticide is contained in each of the first end region, the center region, and the second end region, and a content of the termiticide in the center region is lower than a content of the termiticide in the first end region and in the second end region.

A gypsum panel includes a gypsum core containing a termiticide with poor water solubility, wherein the gypsum core has a first end region, a center region, and a second end region having an equal thickness and extending along a thickness direction from one surface side to another surface side, the termiticide is contained in each of the first end region, the center region, and the second end region, and a content of the termiticide in the center region is lower than a content of the termiticide in the first end region and in the second end region.

Methods to prepare a well cementing slurry include coating particles comprising an expanding agent with a component selected from the group consisting of a phenolic resin, a silica, a calcination product of a polysiloxane oil, and a combination thereof; and combining the coated particles with mix water and hydraulic cement to form a cement slurry for cementing a well.

Methods to prepare a well cementing slurry include coating particles comprising an expanding agent with a component selected from the group consisting of a phenolic resin, a silica, a calcination product of a polysiloxane oil, and a combination thereof; and combining the coated particles with mix water and hydraulic cement to form a cement slurry for cementing a well.

A method of sealing propagating cracks in a sensor-laden cement sheath comprising the steps of monitoring an electrical resistivity of the sensor-laden cement sheath to produce a measured value, wherein the sensor-laden cement sheath comprises a conductive sensor, an on-demand expanding agent, and a cement, activating a heat source when the measured value of the electrical resistivity is greater than an activation threshold, increasing a temperature of the sensor-laden cement sheath with the heat source to an activation temperature, wherein the activation temperature is operable to initiate a reaction between the on-demand expanding agent and water, wherein the activation temperature is greater than a formation temperature, reacting the on-demand expanding agent with water to produce a swelled agent, wherein the swelled agent occupies a greater volume than the on-demand expanding agent, and sealing the propagating cracks in the sensor-laden cement sheath with the swelled agent.

Methods, compositions, and systems for cementing are included. The method comprises providing a cement composition comprising calcium-aluminate cement, water, a cement set retarder, and a cement set activator. The method further comprises introducing the cement composition into a subterranean formation and allowing the cement composition to set in the subterranean formation. The cement composition has a thickening time of about two hours or longer.

Methods, compositions, and systems for cementing are included. The method comprises providing a cement composition comprising calcium-aluminate cement, water, a cement set retarder, and a cement set activator. The method further comprises introducing the cement composition into a subterranean formation and allowing the cement composition to set in the subterranean formation. The cement composition has a thickening time of about two hours or longer.

Embodiments relate to the use of alkali aluminates and alkali silicates with cement kiln dust to form a settable composition for use in subterranean operations. An embodiment provides a method comprising: introducing a settable composition comprising cement kiln dust, an alkali aluminate, an alkali silicate, and an aqueous carrier fluid into a subterranean formation; and allowing the settable composition to set and thereby reduce fluid flow through a portion of the subterranean formation.