Plurality of granules comprising a ceramic core having an outer surface and a shell on and surrounding the core, wherein the core comprises first ceramic particles bound together with a first inorganic binder, wherein the first inorganic binder comprises reaction product of at least alkali silicate and hardener, wherein the shell comprises at least a first concentric layer, wherein the first layer comprises a second inorganic binder and optionally second ceramic particles, wherein if present the second ceramic particles are bound together with the second inorganic binder, wherein the second inorganic binder comprises reaction product of at least alkali silicate and hardener, wherein for a given granule, the first ceramic particles are present in a first weight percent with respect to the total weight of the core and the second ceramic particles, if present in the first layer of the same granule are in a second weight percent with respect to the total weight of the first layer, wherein for a given granule, the first weight percent is greater than the second weight percent, and wherein the granules have a minimum Total Solar Reflectance of at least 0.7. The granules are useful, for example, as roofing granules.

The invention relates to a process for preparing silica-coated particles of an inorganic expanding agent, the silica-coated particles and their use. The silica-coated particles show a delayed release of the expanding agent particularly in alkaline medium and at elevated temperatures. They are therefore useful in the oil and construction industry.

The invention relates to a process for preparing silica-coated particles of an inorganic expanding agent, the silica-coated particles and their use. The silica-coated particles show a delayed release of the expanding agent particularly in alkaline medium and at elevated temperatures. They are therefore useful in the oil and construction industry.

A microcapsule of sustainable self-healing coal mine ventilation sealing material crack. The microcapsule includes a microcapsule core material and a microcapsule wall material. The microcapsule core material is prepared using a bacterial lyophilized powder and a substrate. By using urease-producing bacteria, there is provided a method of protecting bacteria to survive a long time in the cement-based material, supplying sufficient nutrient substances and reducing the impact of the doping of bacteria on the mechanical property of the cement-based material. The bacterial lyophilized powder and substrate are prepared into microcapsules which are added into the cement-based material when the cement-based material is mixed. In this case, once concrete cracks, the microcapsules breaks and the spores in the material are activated to perform normal metabolism so as to induce precipitation of calcium carbonate continuously, thereby continuously realizing self-healing of coal mine ventilation sealing material cracks.

A microcapsule of sustainable self-healing coal mine ventilation sealing material crack. The microcapsule includes a microcapsule core material and a microcapsule wall material. The microcapsule core material is prepared using a bacterial lyophilized powder and a substrate. By using urease-producing bacteria, there is provided a method of protecting bacteria to survive a long time in the cement-based material, supplying sufficient nutrient substances and reducing the impact of the doping of bacteria on the mechanical property of the cement-based material. The bacterial lyophilized powder and substrate are prepared into microcapsules which are added into the cement-based material when the cement-based material is mixed. In this case, once concrete cracks, the microcapsules breaks and the spores in the material are activated to perform normal metabolism so as to induce precipitation of calcium carbonate continuously, thereby continuously realizing self-healing of coal mine ventilation sealing material cracks.

Methods to prepare a well cementing slurry include coating particles comprising an expanding agent with a component selected from the group consisting of a phenolic resin, a silica, a calcination product of a polysiloxane oil, and a combination thereof; and combining the coated particles with mix water and hydraulic cement to form a cement slurry for cementing a well.

Methods to prepare a well cementing slurry include coating particles comprising an expanding agent with a component selected from the group consisting of a phenolic resin, a silica, a calcination product of a polysiloxane oil, and a combination thereof; and combining the coated particles with mix water and hydraulic cement to form a cement slurry for cementing a well.

Provided are: a coated sand having improved fluidity and being capable of improving a filling rate of a casting mold to be obtained; and a coated sand for advantageously manufacturing a casting mold having excellent strength, which coated sand provides a casting mold with good mold-releasability and collapsibility, gives cast products a favorable casting surface, and effectively improves sand adhesion on cast products. The coated sand is formed as a dry granular material having fluidity at room temperature, in which the surface of a refractory aggregate is coated with a solid layer of a water-soluble inorganic binder, and spherical particles of silicone resin having binder-repellency exist on the surface of the binder layer, or form a layer on the surface of the binder layer, a part of the spherical particles being not covered with the water-soluble inorganic binder and being exposed.

Provided are: a coated sand having improved fluidity and being capable of improving a filling rate of a casting mold to be obtained; and a coated sand for advantageously manufacturing a casting mold having excellent strength, which coated sand provides a casting mold with good mold-releasability and collapsibility, gives cast products a favorable casting surface, and effectively improves sand adhesion on cast products. The coated sand is formed as a dry granular material having fluidity at room temperature, in which the surface of a refractory aggregate is coated with a solid layer of a water-soluble inorganic binder, and spherical particles of silicone resin having binder-repellency exist on the surface of the binder layer, or form a layer on the surface of the binder layer, a part of the spherical particles being not covered with the water-soluble inorganic binder and being exposed.

Coated inorganic expanding agent particles comprise a core of an inorganic expanding agent and a sol/gel-formed coating comprising a mixed oxide of two or more metals and/or metalloids, in particular a mixed oxide of silicon and at least one metal and/or metalloid selected from aluminum, boron, titanium, zirconium and zinc. The coated inorganic expanding agent particles are added to cementitious systems to avoid shrinkage during hardening. The coating is effective to delay the expanding effect.