Disclosed is a method of fabricating a construction element, the method comprising the manufacturing of a construction element including a slag, wherein the slag is comprising, on a dry basis and whereby the presence of a metal is expressed as the total of the metal present as elemental metal and the presence of the metal in an oxidized state, a) at least 7% wt and at most 49% wt of iron, Fe, b) at most 1.3% wt of copper, Cu, c) at least 24% wt and at most 44% wt of silicon dioxide, SiO.sub.2, d) at least 1.0% wt and at most 20% wt of calcium oxide, CaO, e) at least 0.10% wt and at most 1.50% wt of zinc, Zn, f) at least 0.10% wt and at most 2.5% wt of magnesium oxide, MgO, and g) at most 0.100% wt of lead, Pb. Further disclosed are improved construction elements comprising the slag.

Chemically modified unpyrolyzed Poaceae fibres having a length of less than 200 mm advantageously comprised between 2 and 100 mm, such as between 2 and 10 mm, said fibres having a water content of less than 40% by weight, and being treated with a treating aqueous dispersion comprising less than 1% by weight of surface treating mixture comprising at least a silanol terminated polydimethylsiloxane, as well as an amino coupling agent.

An acoustical geopolymer panel element includes a layer including a fibre component and a geopolymer binder made from a mixture including ground mineral wool, and an additional layer including mineral wool. The layer including a fibre component and a geopolymer binder has a density in the range of 20-400 kg/m.sup.3, a porosity in the range of 0.75-0.99 and a thickness in the range of 5-75 mm. The ground mineral wool may be ground glass or stone wool and the fibre component may be a wood fibre component, a polymer fibre component and/or a mineral wool component. Further, a geopolymer mixture is provided upon recycling mineral wool which is ground to powder and mixed with an alkali activator component. Additionally, a method for producing acoustical geopolymer panel elements includes grinding elements including mineral wool for provision of a powder component.

A mortar composition, in particular a leveling mortar composition, including: a) 3-45 wt. % of a hydraulic binder, b) 15-80 wt. % of lightweight aggregates, c) 5-50 wt. % of a polymer.

Provided is a ceiling tile coated on at least one surface with an acoustically transparent coating which creates pores at the tile surface and comprises a high Tg polymeric binder, titanium dioxide, and particles selected from the group consisting of void latex particles, hollow glass beads, calcium carbonate, calcium magnesium carbonate, calcined clay and any combination thereof. Compositions for acoustically transparent coatings and methods for making a substrate surface acoustically transparent are provided as well.

A method of printing a 3-dimensional object, the method including the steps of mixing a dry cementitious composition with water, conveying the mixture obtained to a print head, applying the mixture from the print head layer-by-layer to form a 3-dimensional object, curing the 3-dimensional object, wherein the dry cementitious composition includes at least one cement, at least one type of slag, at least one activator for the slag, and at least two lightweight aggregates of different particle size.

A mortar composition, in particular a leveling mortar composition, including: a) 10-50 wt. % of a hydraulic binder, b) 10-25 wt. % of lightweight aggregates, c) 30-50 wt. % of further aggregates which have a particle density that is higher than the particle density of the lightweight aggregates, d) 0.5-5 wt. % of a polymer.

An efficient sound-absorbing lightweight aggregate cellular concrete, a method for preparing the same, and an application thereof. The concrete comprises: 85-95 parts by weight of low-carbon sulfur-aluminum-ferric cementitious materials, 5-15 parts by weight of supplementary cementitious material, 0.6-1.5 parts by weight of functional admixture, 20-60 parts by weight of non-sintered lightweight aggregate, 0.35-0.45 parts by weight of water, and 0.5-1.5 L of preformed foam. The non-sintered lightweight aggregate includes cementitious materials, byproduct gypsum, hydrogen peroxide, water, and expanded perlite. A multi-level pore structure is constructed from expanded perlite pores, hydrogen peroxide foaming pores, and physical foaming pores. The material exhibits a noise reduction coefficient 0.80, a bulk density500 kg/m.sup.3, and a flexural strength 1.5 MPa.

A plant enhanced concrete dry mix comprising (WAV) at least 137.5 parts Kenaf based plant material, derived from Hibiscus cannabinus, which is surface treated with sodium silicate (water glass); not more than 122.2 parts sand and not more than 189.4 parts cement. The plant material may be Kenaf branches that contain a soft core and/or heart surrounded by fibrous material.

A magnesium-based fly ash porous sound-absorbing material with a surface hydrophobically modified, and a preparation method thereof are provided. In the preparation method, a basic magnesium sulfate cement is adopted as a cementing agent and a fly ash is adopted as a mineral admixture to prepare a slurry; foaming is conducted through a physical foaming process in a foaming machine to obtain a foam; and the foam is mixed with the slurry, and a resulting mixture is poured and cured, and then subjected to a surface hydrophobic modification through vapor deposition to obtain the sound-absorbing material. The sound-absorbing material has a density of 251 kg/m.sup.3 to 306 kg/m.sup.3, a noise reduction coefficient (NRC) of 0.65 to 0.7, a compressive strength of 1.8 MPa to 2.2 MPa, and a water contact angle of 129 to 151.