The present invention aims to provide a shrinkage reducing agent that exhibits high performance to reduce the shrinkage of hydraulic materials. The present invention relates to a shrinkage reducing agent for a hydraulic material including a compound that satisfies the following conditions (1) to (4): (1) a ratio represented by {(15-drop flow value of a mortar composition containing the compound)/(15-drop flow value of a mortar free from the compound)}×100 is 120 or less, wherein the (15-drop flow value of a mortar composition containing the compound) means a 15-drop flow value of a mortar composition containing the compound at a solid concentration of 0.1% after 10 minutes mixing and the (15-drop flow value of a mortar free from the compound) means a 15-drop flow value of a mortar free from the compound after 10 minutes mixing; (2) a ratio represented by {(ratio between 15-drop flow values after two hours mixing)/(ratio between 15-drop flow values after 10 minutes mixing)}×100 is 110 or less, wherein the (ratio between 15-drop flow values after two hours mixing) means a ratio of a 15-drop flow value of a mortar composition containing the compound at a solid concentration of 0.1% after two hours mixing to a 15-drop flow value of a mortar free from the compound after two hours mixing, and the (ratio between 15-drop flow values after 10 minutes mixing) means a ratio of a 15-drop flow value of a mortar composition containing the compound at a solid concentration of 0.1% after 10 minutes mixing to a 15-drop flow value of a mortar free from the compound after 10 minutes mixing; (3) the compound has an average particle diameter of 2.2 to 8.5 nm in an alkaline solution; and (4) a product of {(ratio between 15-drop flow values relating to a mortar composition containing the compound at a solid concentration of 1.0%)×(ratio between 15-drop flow values relating to a mortar composition containing the compound at a solid concentration of 0.1%)} is 10,100 or more, wherein the (ratio between 15-drop flow values relating to a mortar composition containing the compound at a solid concentration of 1.0%) means a ratio of a 15-drop flow value of a mortar composition containing the compound at a solid concentration of 1.0% after 10 minutes mixing to a 15-drop flow value of a mortar free from the compound after 10 minutes mixing, and the (ratio between 15-drop flow values relating to a mortar composition containing the compound at a solid concentration of 0.1%) means a ratio of a 15-drop flow value of a mortar composition containing the compound at a solid concentration of 0.1% after 10 minutes mixing to a 15-drop flow value of a mortar free from the compound after 10 minute

Disclosed herein are low density fiber cement articles, such as fiber cement building panels and sheets, comprised of multiple overlaying fiber cement substrate layers having small and uniform entrained air pockets distributed throughout. Also disclosed herein are air entrainment systems and methods for manufacturing aerated low density fiber cement panels or sheets with consistent air void content and uniform air void distribution. Also disclosed herein are air entrainment technologies adapted to work in conjunction with the Hatschek process to produce aerated fiber cement articles having controlled air void content and distribution.

Disclosed herein are low density fiber cement articles, such as fiber cement building panels and sheets, comprised of multiple overlaying fiber cement substrate layers having small and uniform entrained air pockets distributed throughout. Also disclosed herein are air entrainment systems and methods for manufacturing aerated low density fiber cement panels or sheets with consistent air void content and uniform air void distribution. Also disclosed herein are air entrainment technologies adapted to work in conjunction with the Hatschek process to produce aerated fiber cement articles having controlled air void content and distribution.

A cementitious composition including at least one cementitious material and at least one crack reducing admixture including: (i) from 0 to about 5 weight percent of at least one alcohol, based on the total weight of the admixture excluding water; and (ii) a compound having the chemical structure of formula (III): ##STR00001##
wherein: v is an integer from 0 to 50 and w is an integer from 0 to 50, with the proviso that the sum of v and w is at least 1 but not greater than 50. Also, methods of making the cementitious composition, reducing or eliminating the formation of cracks in a cementitious composition as the cementitious composition cures, and limiting the size of cracks which form in a cementitious composition as the cementitious composition cures using an admixture for cementitious compositions as described herein.

A cementitious composition including at least one cementitious material and at least one crack reducing admixture including: (i) from 0 to about 5 weight percent of at least one alcohol, based on the total weight of the admixture excluding water; and (ii) a compound having the chemical structure of formula (III): ##STR00001##
wherein: v is an integer from 0 to 50 and w is an integer from 0 to 50, with the proviso that the sum of v and w is at least 1 but not greater than 50. Also, methods of making the cementitious composition, reducing or eliminating the formation of cracks in a cementitious composition as the cementitious composition cures, and limiting the size of cracks which form in a cementitious composition as the cementitious composition cures using an admixture for cementitious compositions as described herein.

A cementitious composition including at least one cementitious material and at least one crack reducing admixture including: (i) from 0 to about 5 weight percent of at least one alcohol, based on the total weight of the admixture excluding water; and (ii) a compound having the chemical structure of formula (III): ##STR00001##
wherein: v is an integer from 0 to 50 and w is an integer from 0 to 50, with the proviso that the sum of v and w is at least 1 but not greater than 50. Also, methods of making the cementitious composition, reducing or eliminating the formation of cracks in a cementitious composition as the cementitious composition cures, and limiting the size of cracks which form in a cementitious composition as the cementitious composition cures using an admixture for cementitious compositions as described herein.

The disclosed subject matter concerns earth based mixtures, methods of preparing mixtures, and a process of forming articles of manufacture, as well as a process of manufacturing articles in molds configured for compression molding of earth based mixtures in accordance with the disclosed subject matter, including mixtures containing one or more of, e.g., sand, silt, clay, minerals, or any combination thereof.

The disclosed subject matter concerns earth based mixtures, methods of preparing mixtures, and a process of forming articles of manufacture, as well as a process of manufacturing articles in molds configured for compression molding of earth based mixtures in accordance with the disclosed subject matter, including mixtures containing one or more of, e.g., sand, silt, clay, minerals, or any combination thereof.

Electromagnetically-induced cement concrete crack self-healing diisocyanate microcapsules include raw materials, in parts by weight, comprising 15-55 parts of petroleum resin, 5-10 parts of paraffin, 5-10 parts of polyethylene wax, 3-10 parts of magnetic iron powder and 20-67 parts of diisocyanate. The diisocyanate microcapsules use the diisocyanate as a core material, and the petroleum resin/paraffin/polyethylene wax/magnetic iron powder mixture as the shell of the capsule. When micro cracks occur in the concrete, the crack propagation can break partial of the microcapsule inside, the diisocyanate inside the microcapsules flows out and diffuses into the crack and is subjected to a solidifying reaction with water in the concrete, so that the crack is repaired in time; and for the microcapsules that are not broken by cracks, external electromagnetic field can be applied to melt the shell to release the diisocyanate inside, thereby diffusing into cracks and solidify with water to repair them.

Electromagnetically-induced cement concrete crack self-healing diisocyanate microcapsules include raw materials, in parts by weight, comprising 15-55 parts of petroleum resin, 5-10 parts of paraffin, 5-10 parts of polyethylene wax, 3-10 parts of magnetic iron powder and 20-67 parts of diisocyanate. The diisocyanate microcapsules use the diisocyanate as a core material, and the petroleum resin/paraffin/polyethylene wax/magnetic iron powder mixture as the shell of the capsule. When micro cracks occur in the concrete, the crack propagation can break partial of the microcapsule inside, the diisocyanate inside the microcapsules flows out and diffuses into the crack and is subjected to a solidifying reaction with water in the concrete, so that the crack is repaired in time; and for the microcapsules that are not broken by cracks, external electromagnetic field can be applied to melt the shell to release the diisocyanate inside, thereby diffusing into cracks and solidify with water to repair them.