A cementitious composition with accelerated curing at low temperatures particularly at temperatures <5° C., especially at temperatures <0° C. The cementitious composition consists of 2 components with a first component A including at least one ordinary Portland cement, at least one cement selected from calcium aluminate cement and/or calcium sulfoaluminate cement, a powder P, selected from the group consisting of carbonates or hydrogen carbonates of alkali and/or alkaline earth metals, optionally aggregates, optionally other additives and a second component B comprising at least one accelerator, an anti-freeze agent, water, and optionally other additives. The composition shows increased development of compressive strength, maintain good workability, and have particularly low shrinkage, also when cured at temperatures <5° C., especially <0° C., and as low as −10° C.

A cementitious composition with accelerated curing at low temperatures particularly at temperatures <5° C., especially at temperatures <0° C. The cementitious composition consists of 2 components with a first component A including at least one ordinary Portland cement, at least one cement selected from calcium aluminate cement and/or calcium sulfoaluminate cement, a powder P, selected from the group consisting of carbonates or hydrogen carbonates of alkali and/or alkaline earth metals, optionally aggregates, optionally other additives and a second component B comprising at least one accelerator, an anti-freeze agent, water, and optionally other additives. The composition shows increased development of compressive strength, maintain good workability, and have particularly low shrinkage, also when cured at temperatures <5° C., especially <0° C., and as low as −10° C.

In one embodiment, a retarded acid system comprises an aqueous acid and a retarding surfactant. The aqueous acid may comprise from 5 wt. % to 25 wt. % of a strong acid, that is, an acid having a K.sub.a greater than or equal to 0.01. The aqueous acid may further comprise from 75 wt. % to 95 wt. % water. The retarding surfactant may have the general chemical formula R—(OC.sub.2H.sub.4).sub.X—OH where R is a hydrocarbon having from 11 to 15 carbon atoms and x is an integer from 6 to 10. The retarding surfactant may have a hydrophilic-lipophilic balance from 8 to 16.

In one embodiment, a retarded acid system comprises an aqueous acid and a retarding surfactant. The aqueous acid may comprise from 5 wt. % to 25 wt. % of a strong acid, that is, an acid having a K.sub.a greater than or equal to 0.01. The aqueous acid may further comprise from 75 wt. % to 95 wt. % water. The retarding surfactant may have the general chemical formula R—(OC.sub.2H.sub.4).sub.X—OH where R is a hydrocarbon having from 11 to 15 carbon atoms and x is an integer from 6 to 10. The retarding surfactant may have a hydrophilic-lipophilic balance from 8 to 16.

Methods and apparatus are disclosed for producing seeds that are transformed into hollow spheres. A seed includes a core and a coating. Upon heating, the coating becomes viscous and expands responsive to an internal gas pressure created by the core. Example applications for the seeds and/or cores are disclosed, including bricks and other construction materials having the hollow spheres incorporated therein.

A structure for protecting a substrate. The structure comprises an inner tie coat layer which can bond to the substrate, a geopolymer foam layer, and an outer protective layer. The geopolymer foam layer is the reaction product of a mixture comprising an aluminosilicate source, an alkali activator, reinforcing fibres, and a plurality of microparticles.

A structure for protecting a substrate. The structure comprises an inner tie coat layer which can bond to the substrate, a geopolymer foam layer, and an outer protective layer. The geopolymer foam layer is the reaction product of a mixture comprising an aluminosilicate source, an alkali activator, reinforcing fibres, and a plurality of microparticles.

An insulating product for the refractory industry or an insulating material as intermediate for production of such a product, and a corresponding insulating material/insulating product are provided. Likewise the use of a matrix encapsulation process in the production of an insulating product for the refractory industry and a corresponding insulating product and/or an insulating material as intermediate for production of such a product are provided.

An insulating product for the refractory industry or an insulating material as intermediate for production of such a product, and a corresponding insulating material/insulating product are provided. Likewise the use of a matrix encapsulation process in the production of an insulating product for the refractory industry and a corresponding insulating product and/or an insulating material as intermediate for production of such a product are provided.

A system and method for applying a construction material is provided. The system may include a batching and mixing device configured to mix blast furnace slag material, geopolymer material, alkali-based powder, and sand to generate a non-Portland cement-based material, the non-Portland cement-based material including 4% to 45% geopolymer material by weight; greater than 0% to 40% blast furnace slag material by weight, 10% to 45% alkali by weight, 20% to 90% sand by weight, less than 1% sulfate by weight, and/or no more than 5% calcium oxide by weight; a conduit configured to transport the non-Portland cement-based material from the batching and mixing device; and a nozzle configured to receive the non-Portland cement-based material and combine the transported non-Portland cement-based material with liquid to generate a partially liquefied non-Portland cement-based material, wherein the nozzle is further configured to pneumatically apply the partially liquefied non-Portland cement-based material to a surface.