A curing accelerator composition for building chemical mixtures comprises a mineral constituent and a polymeric water-soluble dispersant. The mineral constituent comprises a semi-ordered calcium silicate hydrate having an apparent crystallite size of 15 nm or less and less than 35% by weight of crystalline phases other than the semi-ordered calcium silicate hydrate. The composition displays a more pronounced accelerating effect than comparative compositions in which the mineral component comprises a calcium silicate hydrate having a higher degree of crystallinity.

Described are cementitious reagent materials produced from globally abundant inorganic feedstocks. Also described are methods for the manufacture of such cementitious reagent materials and forming the reagent materials as microspheroidal glassy particles. Also described are apparatuses, systems and methods for the thermochemical production of glassy cementitious reagents with spheroidal morphology. The apparatuses, systems and methods makes use of an in-flight melting/quenching technology such that solid particles are flown in suspension, melted in suspension, and then quenched in suspension. The cementitious reagents can be used in concrete to substantially reduce the CO.sub.2 emission associated with cement production.

Fast-setting Portland cement compositions for filling voids, such as mine shafts and excavated utility trenches, are described. The Portland cement compositions set quickly and are useful when traditional slow setting compositions are less desirable. The acceleration of the set time results from the addition of dry calcium chloride to the Portland cement composition. The compositions consist of Portland cement, dry calcium chloride, water and sometimes preformed cellular foam. Some compositions can include also include fly ash. The compositions may have a compressive strength of between 0 psi and 30 psi after 4 hours, a compressive strength of between 30 psi and 120 psi after 24 hours, a compressive strength of between 200 psi and 500 psi after 28 days, a penetration resistance of between 0.1 tsf and 5 tsf after 10 hours, a penetration resistance of between 0.8 tsf and 10 tsf after 24 hours, and a removability modulus of between 0.2 and 1.0 after 28 days. Also disclosed are methods of filling a void with fast-setting Portland cement.

The invention provides a low density cement composition. The composition includes a cement component, a glass sphere component, a bentonite component, a fine calcium carbonate component, a medium calcium carbonate component, a silica sand component, and a silica flour component.

A visible-light-photocatalyzed composite light-transmitting concrete contains several bundles of optical fibers, the optical fibers are coated with a protective layer on their outer surface, the protective layer contains a visible light photocatalyst, and the concrete has several gas-permeable pores. Such concrete is prepared by mixing a visible light photocatalyst and a light-transmitting glue, applying the mixture to the surface of optical fibers to form a protective layer, and using optical fibers in the concrete. The resulting concrete has dual properties of light transmittance and photocatalytic oxidation of gas-phase pollutants under visible light irradiation. The visible-light-photocatalyzed composite light-transmitting concrete significantly breaks through the limitation of photocatalytic concrete to light sources, so that gas-phase pollutants can be removed under visible light irradiation through photocatalysis of light-transmitting concrete. It also has good mechanical properties, decorativeness, and functional practicability due to coated optical fibers.

The present invention relates to stretched polyolefin fibers comprising a polymer comprising at least one polymeric modifier selected from olefinic polymers modified with an acid and/or an acid anhydride, the use of these fibers in the reinforcement of cementitious compositions, and cementitious composition containing these fibers.

An aggregate includes a polymeric foam present in a range of about 80 vol % to about 85 vol % of the aggregate. A cementitious matrix is present in a range of about 10 vol % to about 13 vol % of the aggregate. One or more resins are present in an amount of less than about 2 vol % of the aggregate, and one or more reinforcing fibers are present in an amount of less than about 1 vol % of the aggregate.

A composition, utility material, and method of making a utility material is disclosed. A composition having an improved setting time may include a plurality of microparticles mixed with a sodium silicate binder and an isocyanate setting agent, where the microparticle composition has a setting time of less than or equal to one hour. A utility material may be a wallboard that includes the composition.

The invention relates to use of nano-fibrillar cellulose as an gas-entrainment stabilizer, which when used in cementitious materials, provides improved gas pore structure quality and/or stability and/or robustness with regard to water content variation. The invention further relates to a method for stabilizing gasentrainment of cementitious materials and to a method for providing cementitious material with improved air pore structure quality and/or stability and/or robustness with regard to water content variation.

Composite fibers and methods of manufacturing composite fibers for the reinforcement of concrete are provided. The composite fibers include fibers and a polymeric coating. The composite fibers have a length of about 10 mm to about 80 mm and an equivalent diameter from about 0.3 mm to about 2 mm. A method for reinforcing concrete using the composite fibers is further provided.