A process for the hydrophobization of a porous silica based compound involves the steps of providing a composition (I) containing a porous silica based compound, treating the composition (I) with a composition (II) containing hexamethyldisiloxane or its hydrolyzed form, and removing the treated silica based compound. The porous silica based compound obtained by the process is useful. A porous silica based compound obtained or obtainable by the process can be used for medical and pharmaceutical applications, as adsorbents, for cosmetic applications, as an additive for food, as a catalyst support, for the preparation of sensors, or for thermal insulation.

A process for the hydrophobization of a porous silica based compound involves the steps of providing a composition (I) containing a porous silica based compound, treating the composition (I) with a composition (II) containing hexamethyldisiloxane or its hydrolyzed form, and removing the treated silica based compound. The porous silica based compound obtained by the process is useful. A porous silica based compound obtained or obtainable by the process can be used for medical and pharmaceutical applications, as adsorbents, for cosmetic applications, as an additive for food, as a catalyst support, for the preparation of sensors, or for thermal insulation.

A method for reducing or avoiding an alkali-aggregate reaction in a cured concrete. The method includes providing a curable concrete mixture which includes alkali-sensitive aggregates (A), at least one organosilicon compound (B) and/or at least one siloxane (B2). Mass hydrophobization of the curable concrete mixture is achieved by way of adding at least one organosilicon compound (B) to the curable concrete mixture prior to its curing thereby reducing or avoiding an alkali-aggregate reaction in the cured concrete.

A method for reducing or avoiding an alkali-aggregate reaction in a cured concrete. The method includes providing a curable concrete mixture which includes alkali-sensitive aggregates (A), at least one organosilicon compound (B) and/or at least one siloxane (B2). Mass hydrophobization of the curable concrete mixture is achieved by way of adding at least one organosilicon compound (B) to the curable concrete mixture prior to its curing thereby reducing or avoiding an alkali-aggregate reaction in the cured concrete.

An object of the present invention is to obtain a cement-based calcined board-shaped construction material having improved impact resistance.

The cement-based calcined board-shaped construction material of the present invention is characterized by being produced by adding 0.5 to 5 wt % of a ceramic inorganic fiber and/or a mineral inorganic fiber to 100 wt % of a compound comprising 5 to 40 wt % of Portland cement, 5 to 30 wt % of a glass powder, and a remainder occupied by a refractory aggregate mainly composed of a silica-alumina refractory raw material, kneading the resulting material, then shaping the kneaded material into an elongated board shape by extrusion, and subsequently calcining the shaped material.

Also, it is the cement-based calcined board-shaped construction material which is produced by sticking a glass fiber sheet to the rear side of the cement-based calcined board-shaped construction material.

An insulating product for the refractory industry or an insulating material as intermediate for production of such a product, and a corresponding insulating material/insulating product are provided. Likewise the use of a matrix encapsulation process in the production of an insulating product for the refractory industry and a corresponding insulating product and/or an insulating material as intermediate for production of such a product are provided.

An insulating product for the refractory industry or an insulating material as intermediate for production of such a product, and a corresponding insulating material/insulating product are provided. Likewise the use of a matrix encapsulation process in the production of an insulating product for the refractory industry and a corresponding insulating product and/or an insulating material as intermediate for production of such a product are provided.

An investment powder which is safer than conventional powders comprising tricalcium phosphate, and being substantially or entirely free of free silica in the respiratory portion yet providing an overall expansion at 750° C. of 1% or higher sufficient to prevent mould cracking during casting. A method of making a casting comprising forming a slurry by mixing a gypsum bonded investment powder with water, pouring the slurry into a stainless steel flask around a low melting point material model, allowing the slurry to set to define a mould, heating the mould to burn out the model and casting material into the mould wherein the stainless steel flask consists of a 400 series martensitic stainless steel.

An investment powder which is safer than conventional powders comprising tricalcium phosphate, and being substantially or entirely free of free silica in the respiratory portion yet providing an overall expansion at 750° C. of 1% or higher sufficient to prevent mould cracking during casting. A method of making a casting comprising forming a slurry by mixing a gypsum bonded investment powder with water, pouring the slurry into a stainless steel flask around a low melting point material model, allowing the slurry to set to define a mould, heating the mould to burn out the model and casting material into the mould wherein the stainless steel flask consists of a 400 series martensitic stainless steel.

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.