It has been unexpectedly discovered that the addition of a natural or other pozzolan to non-spec coal ash significantly improves the properties of the non-spec coal ash to the extent it can be certified under ASTM C618 and AASHTO 295, as either a Class F or Class C coal 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 coal ash into certifiable Class F coal ash. Additionally, this disclosure provides a method of converting a Class C coal ash to a more valuable Class F coal ash. This discovery will extend diminishing Class F coal ash supplies and turn non-spec coal ash waste streams into valuable, certified coal ash pozzolan which will protect and enhance concrete, mortars and grouts.

A galvanic anode system for the corrosion protection of steel in concrete includes a galvanic anode material, which includes of zinc and alloys thereof, embedded in a solid electrolyte, and is characterized in that the galvanically available surface is larger, preferably at least twice as large, as the total geometrical surface of the metal anode. The galvanic anode system is also characterized in that, during operation, during which the anode disintegrates as a sacrificial anode, the galvanically active anode surface is reduced only slightly, preferably is not reduced up to at least 50%, in particular 75%, of the time during use.

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.

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.

Provided herein is a cementitious composition comprising a photoactivator, wherein the photoactivator is capable of converting NOx to NO.sub.2 or NO.sub.3 when exposed to ultraviolet (U.V.) or visible light.

[A] curable mixture configured to set in the presence of water, wherein the mixture comprises magnesium oxide, a primary cementitious component and at least one accelerant and at least one second accelerant, the at least one second accelerant is different than the at least one first accelerant, wherein a proportion by weight of the at least one second accelerant is equal to or less than 2% of a proportion of magnesium oxide by weight of the mixture. A proportion by weight of the primary cementitious component is 80% to 120% of a proportion of magnesium oxide by weight.

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 for the corrosion inhibition, and optionally rehabilitation, of metal reinforcements present in a hardened concrete construction having one or more surfaces that are exposed to chloride intrusion, wherein the method comprises the step of applying an aqueous alkali metal nitrate solution, an aqueous alkaline earth metal nitrate solution, an aqueous zinc nitrate solution, an aqueous aluminium nitrate solution, an aqueous ammonium nitrate solution or a mixture thereof on one or more of the surfaces. The present disclosure also relates to the use of an aqueous alkali metal nitrate solution, an aqueous alkaline earth metal nitrate solution, an aqueous zinc nitrate solution, an aqueous aluminium nitrate solution, an aqueous ammonium nitrate solution or a mixture thereof as a corrosion inhibitor by applying it on one or more surfaces of hardened concrete construction comprising metal reinforcements that are exposed to chloride intrusion. Furthermore, the present disclosure relates to a corrosion inhibiting composition for inhibition of corrosion of metal reinforcements present in a hardened concrete construction having one or more surfaces that are exposed to chloride intrusion.

A cement grout material which does not freeze even in an environment where the ambient temperature can be 5 C. or below, and does not require fuel or large-scaled equipment for maintaining curing temperature. Lithium nitrite is added to a cement grout material that contains cement, water and an admixture. By setting the weight ratio of the lithium nitrite to the cement to a value from 3 to 10% by weight, freezing of the grout material is able to be prevented even in an installation environment where the ambient temperature can be 5 C. during the initial stage of installation. By setting the weight ratio of the lithium nitrite to the cement to a value from 4.5 to 8% by weight, freezing of the grout material is able to be prevented even in an installation environment where the ambient temperature can be 10 C. during the initial stage of installation.

It has been unexpectedly discovered that the addition of a natural or other pozzolan to non-spec coal ash significantly improves the properties of the non-spec coal ash to the extent it can be certified under ASTM C618 and AASHTO 295, as either a Class F or Class C coal 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 coal ash into certifiable Class F coal ash. Additionally, this disclosure provides a method of converting a Class C coal ash to a more valuable Class F coal ash. This discovery will extend diminishing Class F coal ash supplies and turn non-spec coal ash waste streams into valuable, certified coal ash pozzolan which will protect and enhance concrete, mortars and grouts.