A process for treating a substrate made of stone material, preferably in the form of slabs, is provided which process improves the mechanical, thermal and catalytic properties of the substrate. The process includes applying a protective coating to the outer surface of the substrate made of stone material and, to improve adhesion of the protective coating to the outer surface of the substrate, preliminarily subjecting the substrate to one or more pre-treatment steps that eliminate or reduce the presence of pollutants and porosity on the surface of the substrate. The pre-treatment of the substrate made of stone material comprises at least one step of treatment under vacuum conditions inside an autoclave, preferably under pressure conditions lower than 10.sup.2 mbar. Then, after having brought the substrate back to ambient pressure, it is possible to apply and effectively adhere the protective coating to the surface of the stone material.

The present invention relates to a dye mixture for determining the readiness for covering of levelling compounds, and also an application device which includes such a dye mixture. The present invention further relates to the use of the dye mixture for determining the readiness for covering of levelling compounds.

The present invention relates to a dye mixture for determining the readiness for covering of levelling compounds, and also an application device which includes such a dye mixture. The present invention further relates to the use of the dye mixture for determining the readiness for covering of levelling compounds.

The present invention provides a concrete protective agent and a preparation method thereof, and a concrete protective film and a preparation method thereof. The concrete protective agent provided in the present invention includes the following components: water, oxalic acid, a defoaming agent, and a film-forming agent. When the concrete protective agent provided in the present invention is used for concrete protection, oxalic acid in the protective agent can react with calcium ions in concrete for in situ generation of calcium oxalate monohydrate inside and on a surface of concrete to obtain a protective film with strong adhesion to concrete. The film-forming agent in the protective agent is used as a template to adjust and control growth of calcium oxalate crystals, so as to improve waterproof performance and corrosion resistance to sulfate and chloride ions of the protective film. Preparation methods provided in the present invention are simple and practical and are suitable for mass production.

The present invention is to provide an economical and efficient method of reducing drying shrinkage of a cement-based hardened body without requiring the cost and/or the labor and time. A cement-based hardened body is impregnated with a solution containing urea or a solution containing sulfate together with urea. An impregnation treatment may be by a method of coating or spraying the cement-based hardened body with the solution, or alternatively, immersing the cement-based hardened body in the solution containing both urea and sulfate for a predetermined period of time. The solution containing both urea and sulfate may be a solution prepared simply by dissolving both urea and sulfate in water. Besides, there are no particular limitations on a liquid allowing dissolution of both urea and sulfate, so long as it causes no impairment of a drying shrinkage reduction effect, and therefore, a solution having the drying shrinkage reduction effect in itself is also applicable for use of a solution containing both urea and sulfate in a state of being dissolved in such solution.

The present invention is to provide an economical and efficient method of reducing drying shrinkage of a cement-based hardened body without requiring the cost and/or the labor and time. A cement-based hardened body is impregnated with a solution containing urea or a solution containing sulfate together with urea. An impregnation treatment may be by a method of coating or spraying the cement-based hardened body with the solution, or alternatively, immersing the cement-based hardened body in the solution containing both urea and sulfate for a predetermined period of time. The solution containing both urea and sulfate may be a solution prepared simply by dissolving both urea and sulfate in water. Besides, there are no particular limitations on a liquid allowing dissolution of both urea and sulfate, so long as it causes no impairment of a drying shrinkage reduction effect, and therefore, a solution having the drying shrinkage reduction effect in itself is also applicable for use of a solution containing both urea and sulfate in a state of being dissolved in such solution.

A process for treating a substrate made of stone material, preferably in the form of slabs, is provided which process improves the mechanical, thermal and catalytic properties of the substrate. The process includes applying a protective coating to the outer surface of the substrate made of stone material and, to improve adhesion of the protective coating to the outer surface of the substrate, preliminarily subjecting the substrate to one or more pre-treatment steps that eliminate or reduce the presence of pollutants and porosity on the surface of the substrate. The pre-treatment of the substrate made of stone material comprises at least one step of treatment under vacuum conditions inside an autoclave, preferably under pressure conditions lower than 10.sup.2 mbar. Then, after having brought the substrate back to ambient pressure, it is possible to apply and effectively adhere the protective coating to the surface of the stone material.

A process for hydrophobization of concrete or mortar using an aqueous dispersion containing an alkylketene dimer, at least one emulsifier and a condensation product of phenol sulfonic acid and formaldehyde, naphthalene sulfonic acid and formaldehyde, or naphthalene sulfonic acid, phenol, formaldehyde and urea; and the concrete or mortar obtainable by the process. The process allows effective mass and surface hydrophobization of concrete.

A process for hydrophobization of concrete or mortar using an aqueous dispersion containing an alkylketene dimer, at least one emulsifier and a condensation product of phenol sulfonic acid and formaldehyde, naphthalene sulfonic acid and formaldehyde, or naphthalene sulfonic acid, phenol, formaldehyde and urea; and the concrete or mortar obtainable by the process. The process allows effective mass and surface hydrophobization of concrete.

The present invention concerns combinations of a water repellent alkyl ketene dimer as a component (I) and a water repellent metal alcoholate as a component (II) that are strongly synergistic in repelling water from water absorbing surfaces, resulting in a surprisingly long water droplet absorption time. The combinations of the invention can be applied to the surface of any material that has water absorbing properties such as, but not limited to, wood, woven and non-woven sheeting materials, paper, building materials, gypsum board, and leather.