A manufacturing method of a plugged honeycomb structure including a plugging material preparing step of mixing a ceramic raw material, a pore former, a thickener, an organic binder, a dispersing agent, and water and preparing the plugging material which is slurried, to form the plugging portions, wherein the plugging material preparing step includes: a powder mixing step of mixing the ceramic raw material, the pore former, the organic binder and the dispersing agent each of which is constituted of powder, at predetermined blend ratios, a thickener mixing step of adding and mixing the thickener to a powder mixture obtained by the powder mixing step, and a kneading step of adding the water to a thickener added mixture obtained by the thickener mixing step, to perform kneading.

A manufacturing method of a plugged honeycomb structure including a plugging material preparing step of mixing a ceramic raw material, a pore former, a thickener, an organic binder, a dispersing agent, and water and preparing the plugging material which is slurried, to form the plugging portions, wherein the plugging material preparing step includes: a powder mixing step of mixing the ceramic raw material, the pore former, the organic binder and the dispersing agent each of which is constituted of powder, at predetermined blend ratios, a thickener mixing step of adding and mixing the thickener to a powder mixture obtained by the powder mixing step, and a kneading step of adding the water to a thickener added mixture obtained by the thickener mixing step, to perform kneading.

A cement mixture for applying to a ceramic honeycomb body that includes: (i) inorganic ceramic particles; (ii) an inorganic binder; (iii) an organic binder containing a hydrophilic polymer and a hydrophilic additive comprising a polymer with a different composition than the composition of the hydrophilic polymer, the additive having a weight average molecular weight (M.sub.w) of at least 1,000,000 g/mol; and (iv) an aqueous liquid vehicle.

A honeycomb filter comprising a pillar-shaped honeycomb structure body having a porous partition wall and a plugging portion, wherein a thickness of the partition wall is 0.257 mm or less, a porosity of the partition wall is 52 to 57%, an average pore diameter of the partition wall is 6 to 13 .Math.m, a number per unit area of pores which exist at a surface of the partition wall and which have equivalent circle opening diameters exceeding 3 .Math.m is 800 to 1500 /mm.sup.2, an average equivalent circle opening diameter of pores which exist at a surface of the partition wall and which have equivalent circle opening diameters exceeding 3 .Math.m is 8.0 to 12.0 .Math.m, and in a pore diameter distribution of the partition wall, D10 is 2.0 to 5.5 .Math.m, D90 is 13.0 to 25.5 .Math.m, and (Log(D90)-Log(D10))/Log(D50) is 0.84 or less.

A porous ceramic honeycomb body (10) including intersecting walls that form channels (22) extending axially from a first end face to a second end face and layered plugs (62) comprised of a first layer (64) disposed on channel walls and a second layer (66) disposed inward toward an axial center of each respective channel on the first layer. The plugs seal at least one of a first portion of the channels at the first end face and a second portion of channels at the second end face of the porous ceramic honeycomb body.

A porous ceramic honeycomb body (10) including intersecting walls that form channels (22) extending axially from a first end face to a second end face and layered plugs (62) comprised of a first layer (64) disposed on channel walls and a second layer (66) disposed inward toward an axial center of each respective channel on the first layer. The plugs seal at least one of a first portion of the channels at the first end face and a second portion of channels at the second end face of the porous ceramic honeycomb body.

A cement mixture for applying to a honeycomb body that includes: (i) inorganic ceramic particles; (ii) an inorganic binder; (iii) an organic binder comprising one or more of a hydrophilic polymer and a hydrophilic additive; and (iv) an aqueous liquid vehicle. The cement mixture exhibits a cement viscosity of less than 7000 Pa.Math.s at a shear rate of less than 0.1/sec and greater than 25 Pa.Math.s at a shear rate from 20/sec to 100/sec.

A cement mixture for applying to a honeycomb body that includes: (i) inorganic ceramic particles; (ii) an inorganic binder; (iii) an organic binder comprising one or more of a hydrophilic polymer and a hydrophilic additive; and (iv) an aqueous liquid vehicle. The cement mixture exhibits a cement viscosity of less than 7000 Pa.Math.s at a shear rate of less than 0.1/sec and greater than 25 Pa.Math.s at a shear rate from 20/sec to 100/sec.

A ceramic honeycomb filter comprising a cordierite-type ceramic honeycomb structure having large numbers of flow paths partitioned by porous cell walls, and plugs formed in end portions of predetermined flow paths of the ceramic honeycomb structure; the cell walls having a thermal expansion coefficient Tw (×10.sup.−7/° C.) of 10 or less in the flow path direction between 40° C. and 800° C.; the plugs comprising at least ceramic particles, and 5-25 parts by mass of an amorphous oxide matrix per 100 parts by mass of the ceramic particles; the ceramic particles comprising at least 42-90% by mass of amorphous silica particles, and 10-58% by mass of cordierite particles; and the amorphous silica particles comprising 4-30% by mass of first silica particles having a median particle diameter of 10-40 μm, and 70-96% by mass of second silica particles having a median particle diameter of 70-200 μm.

A ceramic honeycomb filter comprising a cordierite-type ceramic honeycomb structure having large numbers of flow paths partitioned by porous cell walls, and plugs formed in end portions of predetermined flow paths of the ceramic honeycomb structure; the cell walls having a thermal expansion coefficient Tw (×10.sup.−7/° C.) of 10 or less in the flow path direction between 40° C. and 800° C.; the plugs comprising at least ceramic particles, and 5-25 parts by mass of an amorphous oxide matrix per 100 parts by mass of the ceramic particles; the ceramic particles comprising at least 42-90% by mass of amorphous silica particles, and 10-58% by mass of cordierite particles; and the amorphous silica particles comprising 4-30% by mass of first silica particles having a median particle diameter of 10-40 μm, and 70-96% by mass of second silica particles having a median particle diameter of 70-200 μm.