Polyurethane composites and methods of preparing polyurethane composites are described herein. The polyurethane composite can comprise (a) a polyurethane formed by the reaction of (i) one or more isocyanates selected from the group consisting of diisocyanates, polyisocyanates, and mixtures thereof, and (ii) one or more polyols; (b) fly ash comprising 50% or greater by weight, fly ash particles having a particle size of from 0.2 micron to 100 microns; and (c) a coarse filler material comprising 80% or greater by weight, filler particles having a particle size of from greater than 250 microns to 10 mm. The coarse filler material can be present in the composite in an amount of from 1% to 40% by weight, based on the total weight of the composite. The weight ratio of the fly ash to the coarse filler material can be from 9:1 to 200:1.

A lightweight aggregate for use in forming lightweight cementitious mixes and/or concrete is formed by encapsulating a plurality of hydrophobic polymer particles (e.g., expanded polystyrene particles) in an encasement having a first layer of a cementitious material and a second layer of a pozzolan or mineral. The lightweight aggregate can be included as at least part of the aggregate component of a cementitious mix to form a lightweight cementitious mix. The lightweight aggregate and/or lightweight cementitious mix can be used to form lightweight concrete. The encasement of the lightweight aggregate allows the cement of the cementitious mix or concrete composition to bond to the lightweight aggregate, thereby promoting strength and durability of the concrete mixture.

Steel reinforcing cables in concrete are protected against corrosion by injecting a carrier fluid and corrosion inhibitors into interstitial spaces between the wires of the cable at a first location along the cable and causing the fluid to pass through the interstitial spaces between the wires of the cable to a second location along the cable. The cable comprises an array of wires confined together and intimately surrounded by a covering material which is engaged with a periphery of the cable so that there are insufficient interconnected spaces between the cable and the covering material to allow passage of fluid longitudinally along the cable outside the cable itself. The method can be used with pre-stressed concrete, with post-tensioned bonded cables and with extruded un-bonded mono-strand cables.

Steel reinforcing cables in concrete are protected against corrosion by injecting a carrier fluid and corrosion inhibitors into interstitial spaces between the wires of the cable at a first location along the cable and causing the fluid to pass through the interstitial spaces between the wires of the cable to a second location along the cable. The cable comprises an array of wires confined together and intimately surrounded by a covering material which is engaged with a periphery of the cable so that there are insufficient interconnected spaces between the cable and the covering material to allow passage of fluid longitudinally along the cable outside the cable itself. The method can be used with pre-stressed concrete, with post-tensioned bonded cables and with extruded un-bonded mono-strand cables.

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).

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).

A curable binder composition includes: a) at least one organic binder selected from the group made of a1) epoxy resins and curing agents for epoxy resins and a2) polyisocyanates and polyols, and b) at least 50% by weight of slag based on 100% by weight of the binder composition.

Hydrophobic aggregates for use in refractory castables and gunning mixtures and methods of their preparation. The aggregates here are formed by crushing insulating fire brick and coating the resulting particles with a hydrophobic component. The hydrophobic component may be a polydimethylsiloxane having a terminal silanol group. As a result of the coating process, the coated aggregate has very low levels of alkalis. The aggregates may be used to form refractory castables that do not undergo substantial alkaline hydrolysis due to the reduced levels of alkalis. The castables made from these aggregates display superior physical properties, including lower water content, lower permanent linear change, high strength, and superior thermal conductivity/insulation properties, while at the same time possessing lower density and requiring less water to be used during castable formation. These improved properties also are observed in gunning mixtures formed from these aggregates.

Hydrophobic aggregates for use in refractory castables and gunning mixtures and methods of their preparation. The aggregates here are formed by crushing insulating fire brick and coating the resulting particles with a hydrophobic component. The hydrophobic component may be a polydimethylsiloxane having a terminal silanol group. As a result of the coating process, the coated aggregate has very low levels of alkalis. The aggregates may be used to form refractory castables that do not undergo substantial alkaline hydrolysis due to the reduced levels of alkalis. The castables made from these aggregates display superior physical properties, including lower water content, lower permanent linear change, high strength, and superior thermal conductivity/insulation properties, while at the same time possessing lower density and requiring less water to be used during castable formation. These improved properties also are observed in gunning mixtures formed from these aggregates.

Embodiments relate to preparation of expandable particulates and their use in fracturing operations. An embodiment provides a method for treating a subterranean formation comprising: introducing a treatment fluid comprising expandable particulates into the subterranean formation, wherein the expandable particulates each comprise a particulate substrate, a swellable material coating the particulate substrate, and an exterior coating comprising a resin; and depositing at least a portion of the expandable particulates in the subterranean formation.