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.

It is an object of the present invention to provide a composition for manufacturing an flooring element for indoor use comprising a cementitious binding material, a cellulosic fibre blend, wherein the cellulosic fibre blend comprises cellulosic fibres having a first degree of SR fineness and cellulosic fibres having a second degree of SR fineness, when measured according to ISO 5267-1, and wherein the first degree of SR fineness is in the range of from 5 to 45, preferably of from 20 to 40, and the second degree of SR fineness is in the range of from 45 to 80, preferably of from 50 to 70.

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.

The present disclosure relates to a method of cementing comprising: providing a cement composition comprising: water, a cement, and a non-aqueous liquid anti-shrinkage cement additive comprising calcined magnesium oxide and a non-aqueous liquid; introducing the cement composition into a subterranean formation; and allowing the cement composition to set in the subterranean formation. Non-aqueous liquid anti-shrinkage cement additives, cement compositions, and systems are also provided.

Disclosed are a composite gypsum board and a method of preparing composite gypsum board. The board contains a set gypsum core sandwiched between two cover sheets. The core is formed from a slurry containing stucco, water, and optional ingredients such as foaming agent, accelerator, retarder, polyphosphate, starch, and dispersant, and core intumescent material. The board also contains at least one skim coat and/or hard edges. A face skim coat layer can be included on one side of the core, facing a face cover sheet. A back skim coat layer can be included on the other side of the core, facing a back cover sheet. Hard edges are known in the art and can be formed, e.g., continuously from a stucco slurry for forming the face and/or back skim coats. Preferably, the back skim coat layer and/or the hard edges are formed from a slurry containing stucco, water, skim coat or edge intumescent material (which have the same desired characteristics), and other optional additives as desired. The skim coat or edge intumescent material can be composed of the same material as the core intumescent material, if desired, but the skim coat and/or edge intumescent material is present in a higher relative concentration in its respective slurry than the amount of core intumescent material in the core slurry. Examples of suitable intumescent materials include expandable vermiculite (e.g., No. 4 or No. 5 according to the US naming system, or combinations thereof), expandable graphite, perlite, or any combination thereof.

This document relates to methods for providing long-term zonal isolation in oil wells using cement compositions that contain triazine-based polymeric additives. The cement compositions containing the polymeric additives exhibit increased tensile strength, elastic strength, or both, without suffering a decrease in compressive strength, as compared to the same cement without the polymeric additive.

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, and serpentines or mixtures thereof. The composition also includes chloride ions or brine.

The invention relates to a process for preparing silica-coated particles of an inorganic expanding agent, the silica-coated particles and their use. The silica-coated particles show a delayed release of the expanding agent particularly in alkaline medium and at elevated temperatures. They are therefore useful in the oil and construction industry.

Provided herein are fiber reinforced cementitious materials and mixtures with increased crack resistance. The cementitious materials and mixtures include a cement and at least one carbon fiber. Also provide is a fiber reinforced cementitious mortar that includes the fiber reinforced cementitious material to which at least one of water, an aggregate material or a chemical admixture is added.

Methods to prepare a well cementing slurry include coating particles comprising an expanding agent with a component selected from the group consisting of a phenolic resin, a silica, a calcination product of a polysiloxane oil, and a combination thereof; and combining the coated particles with mix water and hydraulic cement to form a cement slurry for cementing a well.