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.

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.

Roofing granules comprising agglomerated inorganic material treated with carbon dioxide gas, and building materials, such as shingles, that include such roofing granules. By fabricating roofing granules from agglomerating inorganic material it is possible to tailor the particle size distribution so as to provide optimal shingle surface coverage, thus reducing shingle weight and usage of raw materials. Additionally, the use of agglomeration permits the utilization of by-products from conventional granule production processes.

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.

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.

Expansive cement compositions for use in subterranean wellbores that include a monophase amorphous hydraulic binder material (MAHBM). The MAHBM may include a plurality of particles having a silica core and an amorphous coating substantially surrounding the silica core. The coating may comprise, for example, a plurality of amorphous α-dicalcium silicate hydrate nanoparticles or microparticles. The MAHBM may be used as an expansion agent in a cement composition or used as an expansive cement by itself.

Expansive cement compositions for use in subterranean wellbores that include a monophase amorphous hydraulic binder material (MAHBM). The MAHBM may include a plurality of particles having a silica core and an amorphous coating substantially surrounding the silica core. The coating may comprise, for example, a plurality of amorphous α-dicalcium silicate hydrate nanoparticles or microparticles. The MAHBM may be used as an expansion agent in a cement composition or used as an expansive cement by itself.

Methods, systems, and apparatus, including computer programs encoded on computer storage media, for processing recycled concrete aggregate (RCA). One of the methods includes obtaining first optical measurements of RCA particles as the RCA particles are conveyed past the first optical sensors; determining, based on the first measurements, an initial characterization of the RCA particles; iteratively performing a carbonation process on the RCA particles, obtaining second optical measurements of the RCA particles, and determining, from the second measurements, a second characterization of the RCA particles, wherein conditions of the carbonation process are initially set based on the initial characterization, and the conditions of the carbonation process are adjusted based on the second characterization; ceasing the iterative performance of the carbonation process in response to the second characterization meeting target carbonation characteristics; iteratively performing a densification process on the RCA particles, obtaining third optical measurements of the RCA particles, and determining, from the third measurements, a third characterization of the RCA particles, wherein conditions of the densification process are initially set based on the initial characterization or the second characterization, and the conditions of the densification process are adjusted based on the third characterization; and ceasing the iterative performance of the densification process in response to the third characterization meeting target densification characteristics.

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.

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.