A composition of a cement additive material to improve durability of cementitious structures, was disclosed. The cement additive composition includes an admixture of one or more of divalent magnesium metal silicates with capacity to act as a latent hydraulic binder in said composition activated by a hydration process under aqueous conditions, and in particular the divalent metal silicate is magnesium-dominated silicate, preferably comprising mineral groups of olivines, orthopyroxenes, amphiboles, talc and serpentines or mixtures thereof. The composition also includes chloride ions or brine. Applications of the compositions are also disclosed, in particular to utilize a property of hydration as a major trigger for the latent hydraulic reaction of magnesium silicates, particularly for said olivines, when exposed to water and brines, in order to obtain a cementitious material becoming self healing.

A method for making geopolymer cementitious binder compositions for cementitious products such as concrete, precast construction elements and panels, mortar and repair materials, and the like is disclosed. The geopolymer cementitious compositions of some embodiments are made by mixing a synergistic mixture of thermally activated aluminosilicate mineral, calcium aluminate cement, a calcium sulfate and a chemical activator with water.

A jointless concrete slab set by pouring a concrete slurry includes a) a concrete mixture; b) a colloidal silica admixture; and c) at least one reinforcing fiber selected from the group of fibers. As the poured concrete slurry cures, the poured slurry hardens into a composite material slab, and the jointless concrete slab defines capillary structures that at least in part fill with silica particles and lime, to produce a gel structure of calcium silicate hydrate. In another exemplary embodiment, the present invention is directed to a process for placing a jointless fiberless slab. The process comprises the steps of a) preparing a concrete slurry; b) pouring the concrete slurry onto the substrate; and c) allowing the concrete slurry to cure. In another exemplary embodiment, the present invention is directed to the product itself; namely, a jointless and/or fiberless concrete slab.

The present invention provides a calcium sulphate-based product (e.g. a wall board) comprising gypsum, a pozzolan source such as a clay additive, rice husk ash or diatomaceous earth and a metal salt additive. The product may be produced by drying an aqueous slurry comprising calcined gypsum, the pozzolan source and the metal salt additive. The clay additive may be a kaolinitic clay. The metal salt additive may be a magnesium salt e.g. magnesium nitrate, magnesium chloride or magnesium hydroxide.

Cementitious binder compositions for cementitious products including a hydraulic cement-based reactive powder blend, an inorganic flow control agent, and a metal-based dimensional movement stabilizing agent including at least one member of the group of lithium salt and lithium base, and methods for making the cementitious binder compositions.

A curing agent comprising methyl isobutyl ketone peroxide and at least one peroxide.

The multi-leg fiber reinforced concrete is concrete in which fibers have been embedded to prevent the concrete from being fractured due to cracks developing therein. Each fiber has multiple legs, defining two and three dimensional structures. At least one fiber is embedded in a volume of concrete, where the at least one fiber has at least first and second legs respectively extending along first and second directions. The first and second directions are angularly oriented with respect to one another between 45 and 135, with each of the first and second legs having a free end and a fixed end. Each free end has a substantially Z-shaped contour. The fixed ends of the first and second legs may be joined together to define a two-dimensional fiber structure. The at least one fiber may be partially coated with a polymeric material, such as polypropylene.

A cement-reduced construction composition comprises a) a cementitious binder comprising one or more calcium silicate mineral phases and one or more calcium aluminate mineral phases, and having a Blaine surface area of at least 3800 cm.sup.2/g, in an amount of 180 to 400 kg per m.sup.3 of the freshly mixed construction composition; b) a fine material having a Dv90 of less than 200 ?m, selected from alkali-activatable binders, rock powders and inorganic pigments, or mixtures thereof, in a total amount of 20 to 200 parts by weight, relative to 100 parts by weight of cementitious binder a); c) optionally, an extraneous aluminate source; d) a sulfate source; and e) a polyol in an amount of 0.3 to 2.5 wt.-%, relative to the amount of cementitious binder a). The composition contains available aluminate, calculated as Al(OH).sub.4, from the calcium aluminate mineral phases plus the optional extraneous aluminate source, per 100 g of cementitious binder a), in a total amount of at least 0.08 mol, if the amount of cementitious binder a) is in the range of 180 to less than 220 kg per m.sup.3 of the freshly mixed composition, at least 0.06 mol, if the amount of cementitious binder a) is in the range of 220 to less than 280 kg per m.sup.3 of the freshly mixed composition, and at least 0.05 mol, if the amount of cementitious binder a) is 280 kg or more per m.sup.3 of the freshly mixed composition; and the molar ratio of total available aluminate to sulfate is 0.4 to 2.0. The construction composition further comprises f) an ettringite formation controller comprising (i) glyoxylic acid, a glyoxylic acid salt and/or a glyoxylic acid derivative; and (ii) at least one of (ii-a) a borate source and (ii-b) a carbonate source, wherein the carbonate source is selected from inorganic carbonates having an aqueous solubility of 0.1 g.Math.L.sup.?1 or more, organic carbonates, and mixtures thereof; and g) a co-retarder selected from (g-1) ?-hydroxy monocarboxylic acids and salts thereof, (g-2) phosphonic acids and salts thereof, (g-3) polycarboxylic acids and salts thereof, and mixtures thereof. The cement-reduced construction composition is a reduced carbon footprint construction composition and exhibits high early strength, high final strength, sufficient open time, high durability, and reduced shrinkage compared to ordinary Portland cement based mixes. Ingredients of the construction composition are abundantly available.

Ceramic honeycomb bodies with a matrix of intersecting walls having an interior portion with a first average bulk porosity, and a skin having a second average bulk porosity, wherein the second average bulk porosity is less than the first average bulk porosity. Methods of manufacturing a ceramic honeycomb bodies include providing a firing cycle for the ceramic honeycomb structure such that at least the skin of the honeycomb structure is subjected to a thermal spike in firing temperature while the interior portion of the matrix is subjected to a lesser spike in firing temperature.

A cementitious mixture for a 3D printer and its relative use are described, more specifically for the production of finished products having a complex geometry using a 3D printing apparatus.