An object to provide a prestressed concrete that can be widely used for general building members, in which a chemical stress induced by an expansive material and a mechanical stress induced by a continuous fiber reinforcing wire are simultaneously used together, and due to a synergistic effect of the mechanical stress and the chemical stress, the strength is increased, the reduction in weight, reduction in thickness, and suppression of cracking are achieved, and the degree of freedom in design increased. To provide a prestressed concrete characterized in that, in a concrete into which a prestress is introduced, a mechanical stress induced by a tensional material and a chemical stress induced by an expansive material for a concrete are introduced simultaneously into the concrete, the tensional material is a continuous fiber reinforcing wire, the expansive material for a concrete is contained in an amount of 5 to 30 kg/m3, and aluminum oxide contained in an amount of 0.2 to 2.0% by weight to the expansive material.

A method for forming a treated reclaimed bottom ash sand and a treated reclaimed bottom ash sand. The method includes providing reclaimed bottom ash sand. The reclaimed bottom ash sand is contacted with an aqueous composition having 0.5 to 3.0 M NaOH for a time greater than about 4 hours. The NaOH contacted reclaimed bottom ash sand is rinsed and decanted and iron is removed to form a treated reclaimed bottom ash sand having reduced hydrogen formation in concrete compared to the hydrogen formation of concrete utilizing reclaimed bottom ash sand. The treated reclaimed bottom ash sand includes reactive aluminum of less than 50% by weight of the reactive aluminum in the reclaimed bottom ash sand and the treated reclaimed bottom ash sand includes less than 2 wt % iron. A concrete formed from the treated reclaimed bottom ash sand is also disclosed.

A composite product includes gypsum in an amount of 60 to 90% by weight, fibers in an amount of 1.5 to 26% by weight substantially homogeneously distributed through the composite, and a rheology-modifying agent in an amount of 0.5 to 6% by weight. The composite is caused or allowed to cure to form a cured composite. The cured composite is a fire resistant component used in a fire-rated door core, a fire-rated door or a fire-rated building panel. The fire resistant component may include a building panel, a door panel, a door core, a door rail, a door stile, a door lock block, a door border, or a door insert.

A method for producing a composite insulating mineral block, includes providing a mineral masonry block including at least one cell with walls having a water absorption rate of less than 5 g/(m.sup.2.Math.s) at 10 minutes, and filling the cell with a mineral cement foam, wherein a cement used to produce the mineral cement foam has an aluminum oxide content of less than 20% by weight of the cement.

A method for producing an insulating composite block including a mineral foam, includes: providing a block including at least one cell having walls which are either sufficiently humid or consist of a water-repellent material, and b. filling the cell with a mineral foam that does not substantially include any calcium aluminate.

A method for forming a treated reclaimed bottom ash sand and a treated reclaimed bottom ash sand. The method includes providing reclaimed bottom ash sand. The reclaimed bottom ash sand is heated with an aqueous composition comprising 0.5 to 3.0M NaOH in a reactor vessel to a temperature of from 40 to 70 degrees Celsius and maintaining the temperature for a time greater than about 4 hours to form a reduced metallic aluminum reclaimed bottom ash sand and iron is removed to form a treated reclaimed bottom ash sand having reduced hydrogen formation in concrete. The treated reclaimed bottom ash sand includes reactive aluminum of less than 50% by weight of the reactive aluminum in the reclaimed bottom ash sand and the treated reclaimed bottom ash sand includes less than 2 wt % iron. A concrete formed from the treated reclaimed bottom ash sand is also disclosed.

A method for forming a treated reclaimed bottom ash sand and a treated reclaimed bottom ash sand. The method includes providing reclaimed bottom ash sand. The reclaimed bottom ash sand is contacted with an aqueous composition having 0.5 to 3.0M NaOH for a time greater than about 4 hours. The NaOH contacted reclaimed bottom ash sand is rinsed and decanted and iron is removed to form a treated reclaimed bottom ash sand having reduced hydrogen formation in concrete compared to the hydrogen formation of concrete utilizing reclaimed bottom ash sand. The treated reclaimed bottom ash sand includes reactive aluminum of less than 50% by weight of the reactive aluminum in the reclaimed bottom ash sand and the treated reclaimed bottom ash sand includes less than 2 wt % iron. A concrete formed from the treated reclaimed bottom ash sand is also disclosed.