A composition for forming fire resistant concrete block, that includes a cementitious binder material comprising alumina cement, recycled fine aggregate, and recycled coarse aggregates, the recycled fine aggregates including 10-50 wt % recycled particulate glass cullet having a particle size of 600 microns or less, a concrete block formed from the composition exhibiting a decrease in thermal conductivity with increasing temperature at temperatures causing the particulate glass cullet to melt. A concrete block fabricated from the composition exhibits a fire resistance of at least three hours, a density below 2000 kg/m.sup.3, and a compressive strength of at least 7 MPa.

A composition for forming fire resistant concrete block, that includes a cementitious binder material comprising alumina cement, recycled fine aggregate, and recycled coarse aggregates, the recycled fine aggregates including 10-50 wt % recycled particulate glass cullet having a particle size of 600 microns or less, a concrete block formed from the composition exhibiting a decrease in thermal conductivity with increasing temperature at temperatures causing the particulate glass cullet to melt. A concrete block fabricated from the composition exhibits a fire resistance of at least three hours, a density below 2000 kg/m.sup.3, and a compressive strength of at least 7 MPa.

The present disclosure provides a geopolymer composition having a controllable setting time comprising: at least one reactive aluminosilicate; at least one retarder; and at least one alkali silicate activator solution.

An apparatus, composition and method for recycling of a material, such as, for example, unhardened concrete. The apparatus includes a storage tank for storing a recycling composition to be applied to the material to be recycled and a control unit configured to control release of the recycling composition from the storage tank.

Dark colored roofing granules include an inert base particle coated with a composition including a metal silicate, a non-clay latent heat reactant, and a dark colored but solar reflective pigment.

Dark colored roofing granules include an inert base particle coated with a composition including a metal silicate, a non-clay latent heat reactant, and a dark colored but solar reflective pigment.

Synthetic aggregates are fabricated from greater than approximately 70 wt % waste starting materials. Starting materials may be selected from granulated ground blast furnace slag, waste concrete fines, or sewage sludge ash, and mixtures thereof. The starting materials are bound together by a hydraulic cementitious binder either added to the starting materials or formed in situ. The waste starting materials, binder, and water are formed into pellets and subjected to a hydraulic reaction and carbonation in an atmosphere of greater than approximately 50% carbon dioxide at temperatures less than approximately 100 C. The resulting synthetic aggregate has a crush strength after a period of hardening equal to or greater than approximately 0.5 MPa.

Synthetic aggregates are fabricated from greater than approximately 70 wt % waste starting materials. Starting materials may be selected from granulated ground blast furnace slag, waste concrete fines, or sewage sludge ash, and mixtures thereof. The starting materials are bound together by a hydraulic cementitious binder either added to the starting materials or formed in situ. The waste starting materials, binder, and water are formed into pellets and subjected to a hydraulic reaction and carbonation in an atmosphere of greater than approximately 50% carbon dioxide at temperatures less than approximately 100 C. The resulting synthetic aggregate has a crush strength after a period of hardening equal to or greater than approximately 0.5 MPa.

Synthetic aggregates are fabricated from greater than approximately 70 wt % waste starting materials. Starting materials may be selected from granulated ground blast furnace slag, waste concrete fines, or sewage sludge ash, and mixtures thereof. The starting materials are bound together by a hydraulic cementitious binder either added to the starting materials or formed in situ. The waste starting materials, binder, and water are formed into pellets and subjected to a hydraulic reaction and carbonation in an atmosphere of greater than approximately 50% carbon dioxide at temperatures less than approximately 100 C. The resulting synthetic aggregate has a crush strength after a period of hardening equal to or greater than approximately 0.5 MPa.

A reformulated barrier material for use as an alternative cover for landfills made from recycled materials which may comprise construction and/or demolition debris to which is added tire derived rubber particles to inhibit the release of hydrogen sulfide gas through the reformulated barrier material to the surrounding atmosphere from the landfill beneath.