Provided are cementitious mixtures and processes for reinforcing a cementitious matrix. In one form of the process for reinforcing a cementitious matrix includes the steps of mixing a mineral cement and one or more populations of synthetic copolymer microfibers including about 1 mol. % to about 25 mol. % and from about 75 mol. % to about 99.5 mol. % of propylene monomeric units.

Methods of manufacturing a ceramic honeycomb body having a honeycomb structure with a matrix of intersecting walls, and a skin disposed on an outer peripheral portion of the matrix where the skin has a first average porosity and the interior portion of the matrix has a second average porosity that is greater than the first average porosity. The methods include coating at least the skin with a fluid formulation containing a sintering aid and subsequently firing the honeycomb structure. In certain embodiments, a glass layer is formed in the skin or in regions of the walls directly adjacent to the skin. In certain embodiments, the coating is applied to a green honeycomb structure, and in other embodiments the coating is applied to a ceramic honeycomb structure. Other honeycomb bodies and methods are described.

Cementitious mixtures, such as concrete, can be reinforced by adding one or more ductile but strong synthetic copolymer microfibers to the mixture. The synthetic copolymer microfibers improve local energy dissipation and bear load, taking the driving force for crack propagation away from the crack tip and thus reinforcing the cementitious mixture against the propagation of microscopic cracks. The resulting mixtures have an improved balance of strength properties.

A shrinkage compensating concrete does not require restraint. The expansive forces developed during hydration compensate for concrete shrinkage, obviating the need for any added internal or external restraint element. Using this new shrinkage compensating concrete, substantially crack-free slabs may be built without using restraining steel bars, fibers, or other separate restraining element. The shrinkage compensating concrete includes a cement that develops internal expansive forces that never exceed the tensile strength of the concrete, such that the internal expansion compensates for the concrete shrinkage. The expansive cement may be an ASTMS, M or S cement, or other expansive cements may also be used.

The invention provides a process for the production of a cementitious material, comprising mixing cement starting materials, a healing agent and a fibrous reinforcing material, wherein the healing agent comprises bacterial material, and wherein the fibrous reinforcing material comprises a biodegradable polymer, having an average molecular weight selected from the range of 10-1500 kg/mol, and wherein the fibrous material comprises fibers having diameters selected from the range of 5-750 m, and having lengths selected from the range of 50 m-150 mm.

An admixture for mineral binder compositions, in particular an after-treatment agent for mineral binder compositions, including at least one water-absorbing substance and at least one shrinkage reducer.

A concrete-forming composition for producing a concrete article including: (a) at least one internal curing agent including a water-insoluble crosslinked cellulose ether wherein the water-insoluble crosslinked cellulose ether has a higher water adsorption capacity compared to typically used superabsorbent polymers and wherein the water-insoluble crosslinked cellulose ether can be successfully and efficiently used as a water-insoluble crosslinked cellulose either internal curing agent in concrete-forming compositions; and (b) a cementitious material; a process for making the above concrete-forming composition; and a concrete article made from the above concrete-forming composition with the objective of reducing autogenous shrinkage and crack formation in the resulting concrete article made from the above concrete-forming composition.

A process of preparing a concrete mixture includes the following steps: (a) providing a nano-sized non-sand silica and water; (b) mixing the non-sand silica with the water to form a silica-water mixture; (c) mixing an acid into the silica-water mixture to form a treated water; (d) mixing Portland cement and the treated water for a time sufficient to wet the Portland cement with the treated water to form a Portland/treated-water mixture; (e) mixing aggregate and the Portland-treated-water mixture to form an uncured concrete; and (f) allowing the uncured concrete to cure to form a cured concrete.

A honeycomb structure including: a honeycomb structure body having porous partition walls which define a plurality of cells extending from an inflow end face to an outflow end face to form through channels for a fluid, and a first circumferential wall which is disposed in at least a part of a circumference of the partition walls, and a second circumferential wall disposed to surround an outer side of the honeycomb structure body, wherein the honeycomb structure body does not have an interface between the partition walls and the first circumferential wall, and in a face perpendicular to an extending direction of the cells, a maximum thickness of the first circumferential wall is from 0.1 to 0.3 mm.

A first circumferential wall disposed in a circumference of partition walls has no interface with the outermost circumference partition wall in a circumferential portion constituted by the partition walls whose wall thickness is larger than that of a central portion constituted by the partition walls in a central region. A maximum thickness of a total of the first circumferential wall and a second circumferential wall disposed to surround an outer side of the first circumferential wall is 1.2-3.0 mm, a difference between the maximum thickness and a minimum thickness of the total is 0.2-1.5 mm, and there is satisfied a relation, 0.5(TBTA)SB/SA100(%)9.0 in which TB and TA indicate average thicknesses (m) of the partition walls in the circumferential and central portion respectively, and SB and SA indicate areas (cm.sup.2) of the circumferential portion and the honeycomb structure in the cross section respectively.