The present disclosure provides a solidifying method of a radionuclide. The solidifying method of the radionuclide includes operations of: providing a low melting point glass including Bi.sub.2O.sub.3, B.sub.2O.sub.3, ZnO and SiO.sub.2; providing a glass mixture mixing a mixture to be treated containing a hydroxide of radionuclide and BaSO.sub.4 and the low melting point glass; and heating the glass mixture.

Methods of cementing include providing a geopolymer cement composition that includes a monophase amorphous hydraulic binder material (MAHBM), a metal silicate, an alkaline activator, and a carrier fluid, introducing the geopolymer cement composition into a subterranean formation, and allowing the geopolymer cement composition to set in the subterranean formation. The MAHBM includes silica or alumina core particulates coated with an amorphous calcium silicate hydrate.

A binder composition for immobilizing a toxic-containing material. This composition has excellent strength developing properties at low temperature and is capable of solidifying soil to suppress the elution of toxic materials from the soil.

Disclosed are: damage-resistant ECMCs that need to work and remain elastic between minus 120° C. and positive 300° C.; ECMCs that need to be able to contain a flame of 1900° C. for more than 90 minutes; and composite structures, especially highly stressed structures. One of the characteristic problems of ceramic matrices is their fragility. Indeed, when a fracture starts, it propagates easily in the matrix. Disclosed are elastic ceramic matrix composites (ECMCs), for which: the ceramic matrix is split into solid “ceramic microdomains” (CMDs); the CMDs are connected to one another by a dense network of “elastic microelements” (EMEs); and the bonds between the EMEs and the CMDs are strong chemical bonds, preferably covalent.

Methods and composition are provided for deriving cement and/or supplementary cementitious materials, such as pozzolans, from one or more non-limestone materials, such as one or more non-limestone rocks and/or minerals. The non-limestone materials, e.g., non-limestone rocks and/or minerals, are processed in a manner that a desired product, e.g., cement and/or supplementary cementitious material, is produced.

Disclosed herein are methods and compositions for cementing. An example method may comprise providing a cement composition. The cement composition may comprise a composite cementitious material comprising a micronized particulate solid and a monophase amorphous hydraulic binder. The micronized particulate solid may have a mean particle size of about 500 microns or less. The cement composition may further comprise water. The method may further comprise introducing the cement composition into a subterranean formation; and allowing the cement composition to set.

A light weight geopolymer concrete, having a specific gravity less than 2.0, more typically between 1 and 1.3, is provided that has compressive strength comparable to or greater than ordinary Portland concrete. The light weight geopolymer concrete has low shrinkage, expansion, and cracking, and substantially no loss of compressive strength when exposed to high temperatures of 800° C. or greater, as would occur in a fire. To be useful as a load bearing member for general applications, such as residential housing, the compressive strength of the light-weight geopolymer concrete should be at least 10 MPa, preferably greater than 12 MPa, for example greater than 15 MPa. For more demanding uses, the compressive strength should be near or at the compressive strength of concrete, that is, greater than 20 MPa, preferably greater than 30 MPa, and optimally greater than 35 MPa. To be useful during and after a fire, the strength must not be reduced by more than 20%, preferably not less than 10%, optimally not reduced at all when exposed to heat up to 800° C. Embodiments of the invention include low-density high-temperature-resistant geopolymer concrete which increases load bearing strength when exposed to temperatures above 400° C., preferably at 800° C. Key constituents for forming most embodiments include a geopolymer source such as fly ash, a cement-coated expanded vermiculite, a fiber such as wollastonite, and soluble silicates such as alkali silicates.

Acid-resistant composite materials and methods of forming acid resistant composite materials are disclosed. The acid resistant composite materials can include one or more monovalent, divalent, or polyvalent cationic metals. The acid resistant composite materials can be used, for example, in the formation of concreate or as a coating for concrete.

Composite cement with improved reactivity and improved fresh properties comprising a hydraulic cement or a caustic activator, a hyaloclastite as pozzolan containing 45-62 wt.-% SiO.sub.2, 10-20 wt.% Al.sub.2O.sub.3, 6-15 wt.-% Fe.sub.2O.sub.3, 7-15 wt.-% CaO, 7-15 wt.-% MgO, 1.5-4 wt.% (K.sub.2O+Na.sub.2O), and having 0-5 wt.-% loss on ignition at 950° C. and ≥50 wt.-% X-ray amorphous phase, and a carbonate filler with an at least bimodal particle size distribution adapted to provide a slope n in a Rosin-Rammler-Sperling-Bennett distribution curve of ≤1.15 in a particle size distribution of the composite cement; a method for manufacturing it, as well as use of a composition comprising the hyaloclastite as pozzolan and the carbonate filler as mineral addition for composite cements comprising a hydraulic cement or a caustic activator.

The present invention lies within the field of construction materials and concerns a process for separating the constituents of hardened concrete, with the aim of extracting the cementitious fraction to be used in the production of thermoactivated recycled cement, involving the essential steps of: (a) crushing the concrete waste; (b) screening the crushed material to separate material smaller than about 1 mm; (c) fragmenting material larger than 1 mm; (d) screening material smaller than 1 mm into various granulometric fractions; (e) high intensity magnetic separation of the material; (f) grinding of the cementitious fraction resulting from the magnetic separation in the previous step to a size that allows its efficient thermoactivation; and (g) obtaining a thermoactivated recycled cement.