Self-stressing engineered composites that include a matrix containing self-stressing reinforcement that is activated by an activator that causes, in situ, the self-stressing reinforcement to transfer at least some of its pre-stress into portions of the matrix adjacent the self-stressing reinforcement. In some embodiments, the activator can be of a self-activating, an internal activating, and/or an external activating type. In some embodiments, the self-stressing reinforcement includes an active component that holds and transfers pre-stress to a matrix and a releasing component that causes the active component to transfer its pre-stress to the matrix. In some embodiments, the self-stressing reinforcement is initially unstressed and becomes stressed upon activation. Various engineered composites, self-stressing reinforcement, and applications of self-stressing engineered composites are disclosed.

Provided herein are fiber reinforced cementitious materials and mixtures with increased crack resistance. The cementitious materials and mixtures include a cement and at least one carbon fiber. Also provide is a fiber reinforced cementitious mortar that includes the fiber reinforced cementitious material to which at least one of water, an aggregate material or a chemical admixture is added.

Described is a method of preparing foams, wherein a suspension comprising an aqueous liquid, particles and at least one surfactant is provided, wherein the at least one surfactant at least partially hydrophobizes a surface of the particles, and wherein the suspension comprising the particles having the at least partially hydrophobized surface is foamed. The at least one surfactant is selected from surfactants having a backbone chain comprising at least nine carbon atoms, the at least one surfactant preferably being an amphiphilic molecule consisting of a tail coupled to a head group, wherein the tail comprises the backbone chain comprising at least nine carbon atoms.

Described is a method of preparing foams, wherein a suspension comprising an aqueous liquid, particles and at least one surfactant is provided, wherein the at least one surfactant at least partially hydrophobizes a surface of the particles, and wherein the suspension comprising the particles having the at least partially hydrophobized surface is foamed. The at least one surfactant is selected from surfactants having a backbone chain comprising at least nine carbon atoms, the at least one surfactant preferably being an amphiphilic molecule consisting of a tail coupled to a head group, wherein the tail comprises the backbone chain comprising at least nine carbon atoms.

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.

A variety of fluid loss control compositions and methods are provided for controlling fluid loss in a cementing operation. As described herein, polyelectrolyte complex nanoparticles and fluid loss control compositions containing polyelectrolyte complex nanoparticles can be effective for fluid loss control in a variety of cementing operations. Methods of making and methods of using the electrolyte complex nanoparticles and fluid loss control compositions containing polyelectrolyte complex nanoparticles are also provided. The polyelectrolyte complex nanoparticles can include a polycation polymer such as a branched chain polyethylenimine, and a polyanion polymer such as polyacrylic acid or poly(vinylsulfonic) acid. The polyelectrolyte complex nanoparticles can contain additional additives such as metal ions or fluid loss additives such as a cellulose polymer.

The present invention provides compositions and methods relative to controlling hydration onset of an alkaline earth metal oxide such as calcium oxide, comprising heating an inorganic alkaline earth metal oxide to sub-calcination temperatures in the presence of organic material comprising a carbohydrate, an amino-carboxylic acid, a hydroxycarboxylic acid, or a mixture thereof. Preferred treated particles comprise at least 40% and more preferably at least 80% by dry weight calcium oxide which is heated in the presence of ascorbic acid and a starch. Treated particles of the present invention manifest an unexpected, surprising hydration induction postponement behavior as demonstrated through calorimetric testing.

The present invention provides compositions and methods relative to controlling hydration onset of an alkaline earth metal oxide such as calcium oxide, comprising heating an inorganic alkaline earth metal oxide to sub-calcination temperatures in the presence of organic material comprising a carbohydrate, an amino-carboxylic acid, a hydroxycarboxylic acid, or a mixture thereof. Preferred treated particles comprise at least 40% and more preferably at least 80% by dry weight calcium oxide which is heated in the presence of ascorbic acid and a starch. Treated particles of the present invention manifest an unexpected, surprising hydration induction postponement behavior as demonstrated through calorimetric testing.

The present invention relates generally to wall repair compounds such as joint compounds, spackling compounds, and the like used to repair imperfections in walls or fill joints between adjacent wallboard panels. Particularly, the present invention relates to such a wall repair compound comprising a dust reduction additive (DRA) that reduces the quantity of airborne dust generated when the hardened compound is sanded. The dust reduction additive also imparts adhesion to the wall repair compounds to which it is added, for example to a joint compound. More specifically, this dust reduction additive is of sufficiently lighter shade to not impact the shade of the joint compound upon addition. In one embodiment, this invention relates to a non-foaming dust reduction additive that comprises paraffin and/or micro-crystalline wax-based emulsion.