The invention relates to a composition having plasma-treated recycled steel fibers within the matrix.

This rapid-hardening mortar composition includes: a rapid-hardening admixture; cement; and a fine aggregate, wherein the cement is contained in an amount of 100 parts by mass to 2,000 parts by mass with respect to 100 parts by mass of the rapid-hardening admixture, the rapid-hardening admixture is a composition that contains: calcium aluminate; inorganic sulfate in an amount of 50 parts by mass to 200 parts by mass with respect to 100 parts by mass of the calcium aluminate; and a setting modifier in an amount of 0.1 parts by mass to 10 parts by mass with respect to 100 parts by mass of the calcium aluminate, and an average particle diameter of the calcium aluminate is in a range of 8 m to 100 m, and an average particle diameter of the setting modifier is in a range of 5 m or less.

A cementitious binder, includes a hydraulic binder in an amount in the range from 50 to 80% by weight of the cementitious binder; a first siliceous based material in an amount in the range from 0.5 to 35% by weight of the cementitious binder, the first siliceous based material having a (SiO.sub.2)/(Al.sub.2O.sub.3) ratio by weight greater than 2.5; a second siliceous based material in an amount in the range from 10 to 25% by weight of the cementitious binder, the second siliceous based material being different from the first siliceous based material and having (a) a (SiO.sub.2)/(Al.sub.2O.sub.3) ratio by weight greater than 10 and (b) a BET specific surface area greater than 5 m.sup.2/g; and an aluminum based material in the range from 0 to 10% by weight of the cementitious binder and having a (SiO.sub.2)/(Al.sub.2O.sub.3) ratio by weight lower than 2.5, wherein 0.09<Al.sub.EFF/(Al.sub.EFF+Si.sub.EFF)<0.28, where Al.sub.EFF=molar content of alumina aluminum in the hydraulic binder, and Si.sub.EFF=molar content of silica in the first siliceous based material for particles having a size lower than 3 m+molar content of silica in the second siliceous based material.

A self-bonding refractory powder product for use in making a slurry for investment casting molds comprising a coarse refractory powder; a Nano-sized powder; and an organic polymer powder, wherein it does not require aqueous colloidal silica to produce slurries used to build investment casting molds. The Nano-sized powder comprises fumed alumina, boehmite, fumed silica, or fumed titanium oxide or combinations thereof. The coarse refractory powder comprises milled zircon, tabular alumina or fused alumina, fused silica, alumino-silicate, zirconia, and yttria or combinations thereof. The organic polymer powder comprises a cellulose-based material.

A railway tie being constructed of an engineered cementitious composite (ECC) material having: (1) a minimum of 2% tensile ductility of ECC, (2) complete absence of alkali-silica reaction (ASR), (3) high fatigue resistance of ECC at least five times that of normal concrete, (4) self-healing ability of ECC requiring only water and air, and (5) customization of ECC for lower stiffness in the tie (60% that of normal concrete) and higher abrasion resistance in the seat (three times that of normal concrete).

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.

It has been unexpectedly discovered that the addition of a natural or other pozzolan to non-spec fly ash significantly improves the properties of the non-spec fly ash to the extent it can be certified under ASTM C618 and AASHTO 295, as either a Class F or Class C fly ash. The natural pozzolan may be a volcanic ejecta, such as pumice or perlite. Other pozzolans may also be used for this beneficiation process. Many pozzolans are experimentally tested and may be used to beneficiate non-spec fly ash into certifiable Class F fly ash. Additionally, this disclosure provides a method of converting a Class C fly ash to a more valuable Class F fly ash. This discovery will extend diminishing Class F fly ash supplies and turn non-spec fly ash waste streams into valuable, certified fly ash pozzolan which will protect and enhance concrete, mortars and grouts.

A method of delivering polymeric microspheres to protect a cementitious composition, such as concrete, from freeze-thaw damage which comprises the addition of a dry blend of mineral powder and dry-expanded polymeric microspheres to cementitious compositions is described. The polymeric microspheres form annulus voids in the cementitious matrix by undergoing thermal contraction as the ambient temperature drops. The annulus voids act as entrained air voids to provide spaces for ice crystals to grow, thereby greatly reducing or eliminating the risk of cracking of the cementitious composition during freezing and thawing.

A self-bonding refractory powder product for use in making a slurry for investment casting molds comprising a coarse refractory powder; a Nano-sized powder; and an organic polymer powder, wherein it does not require aqueous colloidal silica to produce slurries used to build investment casting molds. The Nano-sized powder comprises fumed alumina, boehmite, fumed silica, or fumed titanium oxide or combinations thereof. The coarse refractory powder comprises milled zircon, tabular alumina or fused alumina, fused silica, alumino-silicate, zirconia, and yttria or combinations thereof. The organic polymer powder comprises a cellulose-based material.

It has been unexpectedly discovered that the addition of a natural or other pozzolan to non-spec fly ash significantly improves the properties of the non-spec fly ash to the extent it can be certified under ASTM C618 and AASHTO 295, as either a Class F or Class C fly ash. The natural pozzolan may be a volcanic ejecta, such as pumice or perlite. Other pozzolans may also be used for this beneficiation process. Many pozzolans are experimentally tested and may be used to beneficiate non-spec fly ash into certifiable Class F fly ash. Additionally, this disclosure provides a method of converting a Class C fly ash to a more valuable Class F fly ash. This discovery will extend diminishing Class F fly ash supplies and turn non-spec fly ash waste streams into valuable, certified fly ash pozzolan which will protect and enhance concrete, mortars and grouts.