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.

Some embodiments of the present invention comprise a method of cementing comprising: placing a settable composition into a well bore, the settable composition comprising remediated coal ash, hydraulic cement, and water; and allowing the settable composition to set. Other embodiments comprise a method of cementing comprising: placing a settable composition into a well bore, the settable composition comprising remediated coal ash, calcium hydroxide (lime), and water; and allowing the settable composition to set. Other embodiments comprise a settable composition comprising: remediated coal ash, hydraulic cement, calcium hydroxide, natural pozzolan and water; and allowing the composition to set. Other embodiments comprise a settable composition comprising remediated coal ash and any combination of hydraulic cement, calcium hydroxide, slag, fly ash, and natural or other pozzolan.

The coupled borate/silicate salts-based additive for mortar or concrete controls chloride induced pitting and uniform corrosion of steel rebars embedded in the mortar or concrete with no detrimental effect on compressive strength of mortar/concrete. The silicate compounds may include one or more of the salts of sodium, potassium, lithium, calcium, magnesium, manganese, iron, zinc, aluminum and other transition and valve metals. The borate compounds may include one or more of the salts of alkali and alkaline earth metals, transition, non-transition and valve metals such as sodium, potassium, lithium, calcium, magnesium, manganese, iron, zinc, aluminum and others. The combination of the borate and silicate salts as an additive has been shown to impart high protection to steel rebar surfaces against corrosion, and particularly chloride induced pitting corrosion. The additives are equally effective for mortar as well as concrete. They are also eco-friendly, economical, and are easily applied at construction sites.

High-strength flowable fill compositions are disclosed. The compositions include cement, aggregate (e.g., sand), water, coloring agent, polymer, and fibers. In an embodiment, the compositions include an accelerant, e.g., calcium chloride or sodium bicarbonate and/or an air entraining agent. In an embodiment, the compositions include a water-proofing agent to eliminate efflorescence. The compositions have a compressive strength of between 300 psi and 3000 psi after 1 day, a compressive strength of between 900 psi and 4000 psi after 7 days, and a compressive strength of between 1200 psi and 5000 psi after 28 days.

A cement product including a supplementary cementitious material (SCM) including natural aluminosilicate, and optionally metakaolin, and methods of producing the cement product, and methods of use thereof are provided. The natural aluminosilicate may have, for example, a d97 less than or equal to about 19 m; and may have a d10 less than or equal to about 2 m. The product may also have improved chloride permeability as compared to cement products including natural aluminosilicates having higher d97 and d10 values. Also, the product may also have improved compressive strength and RCPT values when a portion of the natural aluminosilicate in the SCM is replaced with metakaolin.

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.

The present invention relates to coloured fiber cement products as well as to methods for manufacturing such products. In particular, the present invention provides coloured fiber cement products, which fiber cement products are coloured in the mass, and at least comprise on at least part of their outer surface one or more cured layers of a coating composition, which composition at least comprises a binder and a pigment and/or a filler and is characterized by a pigment volume concentration (PVC) of between about 1% and about 20%. The present invention further provides processes for producing these coloured fiber cement products. Finally, the present invention provides uses of the coloured fiber cement products as building materials. In particular embodiments, the fiber cement products produced by the processes of the present invention can be used to provide an outer surface to walls, both internal as well as external, a building or construction, e.g. as fagade plate, siding, etc.