The present invention relates to an apparatus for producing rapid-hardening concrete and a method for producing same, the rapid-hardening concrete being produced by intermixing and dissipating air in normal concrete and adding an early-strength admixture thereto. With respect to forming rapid-hardening concrete, mixed concrete is formed by mixing in a large volume of air bubbles to be discarded, along with an early-strength admixture, to already mixed normal concrete, the early-strength admixture getting evenly dispersed therewithin by means of the ball bearing effect of the air bubbles, and when the mixed concrete is discharged, a rapid-hardening concrete is shotcreted while excess air contained in the mixed concrete is dissipated by means of high-performance air, the slump which was raised due to the large amount of air bubbles having been reduced to the slump range for normal concrete.

A cementitious blend composition and a concrete mix composition preferable for making concrete resistant to high temperatures and alkaline conditions, particularly for making durable concrete for constructing an alumina digester tank in an aluminum smelter. The cementitious blend composition includes at least one hydraulic cement, silica fume (SF), and natural pozzolan (NP), wherein a weight percent ratio of at least one hydraulic cement: SF:NP in the cementitious blend composition lies in the range of (24-63): (5-44): (32-40) with the sum of the weight percentages of the at least one hydraulic cement, the SF, and the NP not exceeding 100%. The concrete mix composition comprises water and the cementitious blend composition, wherein a weight ratio of the water the cementitious blend composition is 0.2-0.5, and wherein the concrete mix composition has a content of the cementitious blend composition of 400-550 kg/m.sup.3.

There is provided a method for operating a cement plant capable of simultaneously optimizing both combustion in a calciner and a heat consumption rate. The method for operating a cement plant includes: feeding first fuel to a calciner; feeding second fuel for maintaining the inside at a burning temperature to a cement kiln along with combustion primary air, and introducing air for cooling cement clinker to a cooler; and feeding a part of the air as secondary air to the cement kiln, feeding as tertiary air to the calciner, and discharging the rest of the air from the cooler, wherein relation between a first oxygen concentration at an exhaust gas outlet of the calciner and a heat consumption rate determined by the first fuel and the second fuel, and relation between a second oxygen concentration at an exhaust gas outlet of the preheater and the heat consumption rate are beforehand obtained, and amounts of the secondary air and the tertiary air are adjusted such that both the first oxygen concentration and the second oxygen concentration fall within a range including values of the oxygen concentrations at which the heat consumption rate becomes at its minimum.

The present invention comprises a product. The product comprises a first mineral in particulate form and having a first pozzolanic reactivity and a second mineral in particulate form and having a second pozzolanic reactivity greater than the first reactivity, wherein the surface of at least some of the particles of the first mineral is at least partially covered with particles of the second mineral. A method of making the composition of the present invention is also disclosed.

An ultra-light, pourable, self-drying cementitious product with improved density control and ultra-low water demand is provided. Compositions and methods for making the products are provided as well, including compositions and methods with ultra-low water demand.

An ultra-light, pourable, self-drying cementitious product with improved density control and ultra-low water demand is provided. Compositions and methods for making the products are provided as well, including compositions and methods with ultra-low water demand.

A mortar mixture for horizontal surfaces or as casting mortar in molds has at least 20% of the mortar mixture by volume being balls composed of expanded silica sand or expanded perlite with the balls being glazed and closed at the surface thereof and filled with air. The expanded perlite balls are mixed with binding agents, additives as binders, an air-void forming agent, chemical admixtures as liquefiers, quick-setting binders, or a combination thereof, and composed of polymers. The method for producing the mortar mixture is performed by sorting perlite sand into various grain sizes by a grading curve. Each individual grain size is then expanded in a trickling channel having multi-stage temperature zones so that the surface of the balls is glazed. The glazed, expanded perlite so produced are mixed together into a homogenous mixture by adding binding agents and cellulose, air-void forming agent, chemical admixtures or a combination thereof.

An ultra-light, pourable, self-drying cementitious product with improved density control and ultra-low water demand is provided. Compositions and methods for making the products are provided as well, including compositions and methods with ultra-low water demand.

An ultra-light, pourable, self-drying cementitious product with improved density control and ultra-low water demand is provided. Compositions and methods for making the products are provided as well, including compositions and methods with ultra-low water demand.

Pumpable process-fluid compositions and methods for establishing hydraulic isolation in cemented subterranean wells comprise more than 1 wt % polyacrylamide and a non-metallic crosslinker. Upon entering voids and cracks in or adjacent to a cement sheath, and contacting the set-cement surfaces, the compositions react and form a seal that prevents further leakage.