The present invention relates to a cementitous composite specifically engineered to possess self-cleaning abilities while maintaining their unique strain-hardening behaviour and the preparation of the said composite. The cementitious composite comprises a hydraulic cement, a plurality of fibers, in particular polyvinyl alcohol fibers wherein the ratio of the plurality of fibers to the hydraulic cement is in a range from 1 to 3% by volume; a self-cleaning agent, in particular nanoparticulate titanium dioxide (TiO.sub.2) wherein the weight ratio of the self-cleaning agent to the hydraulic cement is in a range from 0.01 to 1.

Disclosed are a rock similar material satisfying a water-induced strength degradation characteristic and a preparation method and use thereof. The rock similar material satisfying the water-induced strength degradation characteristic includes an aggregate, a cementing material, and an additive, where the aggregate includes quartz sand, barite powder, and bentonite, and the cementing material includes cement and gypsum.

Portland cement compositions for use in high-temperature, high pressure wells are designed such that the lime-to-silica molar ratio is between 0.5 and 1.0, and the alumina-to-silica molar ratio is between 0.05 and 0.10. After curing and setting at temperatures between 85° C. and 300° C., the cement compositions form tobermorite as an initial and permanent calcium silicate hydrate phase.

A dental self-adhesive resin cement is provided comprising a two-component system. A first catalyst component includes one or more acidic monomers. A second base component includes one or more basic fillers. The mixture of the first and second components is polymerizable and has an initial pH that is acidic immediately after mixing and a pH of at least about pH 8 after polymerization.

A dental self-adhesive resin cement is provided comprising a two-component system. A first catalyst component includes one or more acidic monomers. A second base component includes one or more basic fillers. The mixture of the first and second components is polymerizable and has an initial pH that is acidic immediately after mixing and a pH of at least about pH 8 after polymerization.

This invention relates to a solidifying agent for solidifying radioactive waste, and more particularly to a solidifying-agent composition for solidifying radioactive waste, including alumina cement and a gypsum powder. The solidifying-agent composition including alumina cement and a gypsum powder is capable of effectively minimizing an increase in the volume of a solidified radioactive waste product to a level satisfying physical and chemical safety regulations upon the solidification of radioactive waste.

This invention relates to a solidifying agent for solidifying radioactive waste, and more particularly to a solidifying-agent composition for solidifying radioactive waste, including alumina cement and a gypsum powder. The solidifying-agent composition including alumina cement and a gypsum powder is capable of effectively minimizing an increase in the volume of a solidified radioactive waste product to a level satisfying physical and chemical safety regulations upon the solidification of radioactive waste.

The invention relates to a method for producing a solid construction material which is preferably substantially free of hydraulic binder, comprising the steps of: a. extracting a mineral fraction comprising argillaceous particles of a soil; b. optionally adjusting the particle size of the mineral fraction extracted, in particular in relation to its clay, sand, gravel or loam content, if necessary; c. preparing a first aqueous grout from at least one part of the mineral fraction extracted and optionally adjusted in terms of particle size; d. adding a dispersant that can disperse the argillaceous particles in the first grout in order to obtain a second aqueous grout, e. adding a coagulant that can promote the agglomeration of the argillaceous particles in the second grout in order to obtain an aqueous construction material grout; f introducing the construction material grout into a formwork; and g. allowing the evaporation of the water contained in the material grout in order to obtain a solid construction material.

Mineral particles may provide for wellbore fluids with tailorable properties and capabilities. In some instances, a dry wellbore additive may comprise a plurality of first mineral particles having a specific gravity of about 2.6 to about 20; a plurality of second mineral particles having a specific gravity of about 5.5 to about 20; a plurality of lubricant particles having a specific gravity of about 2.6 to about 20; wherein the first mineral particles, the second mineral particles, and the lubricant particles are different; and wherein the first mineral particles, the second mineral particles, and the lubricant particles have a multiparticle specific gravity of about 3 to about 20.

Mineral particles may provide for wellbore fluids with tailorable properties and capabilities. In some instances, a dry wellbore additive may comprise a plurality of first mineral particles having a specific gravity of about 2.6 to about 20; a plurality of second mineral particles having a specific gravity of about 5.5 to about 20; a plurality of lubricant particles having a specific gravity of about 2.6 to about 20; wherein the first mineral particles, the second mineral particles, and the lubricant particles are different; and wherein the first mineral particles, the second mineral particles, and the lubricant particles have a multiparticle specific gravity of about 3 to about 20.