A prefabricated composite concrete element for use in a corrosive sewer environment. The concrete element has a hollow reinforced cast concrete portion with at least one end having connection details, a premolded corrosion resistant inner plastic liner. The plastic liner lines an interior of the hollow concrete element and the connection details to provide abutting liner faces in an assembled joint to limit exposure through said joint of said concrete portion to corrosive materials arising in said sewer environment. At least two prefabricated composite concrete elements may be assembled end to end at a joint to form a concrete sewer system. Also disclosed are a method of prefabricating such a composite concrete element.

A prefabricated composite concrete element for use in a corrosive sewer environment. The concrete element has a hollow reinforced cast concrete portion with at least one end having connection details, a premolded corrosion resistant inner plastic liner. The plastic liner lines an interior of the hollow concrete element and the connection details to provide abutting liner faces in an assembled joint to limit exposure through said joint of said concrete portion to corrosive materials arising in said sewer environment. At least two prefabricated composite concrete elements may be assembled end to end at a joint to form a concrete sewer system. Also disclosed are a method of prefabricating such a composite concrete element.

Gypsum panels and methods of making the same are provided. A method of making a gypsum panel includes forming a first gypsum slurry by combining stucco, water, a siliconate, and a phosphate salt or polymer, and setting the first gypsum slurry to form at least part of a core of the gypsum panel, wherein the gypsum panel displays a 2-hour water absorption test weight increase of at least 10 weight percent less than an otherwise identical comparative panel containing no phosphate salt or polymer in its core.

Gypsum panels and methods of making the same are provided. A method of making a gypsum panel includes forming a first gypsum slurry by combining stucco, water, a siliconate, and a phosphate salt or polymer, and setting the first gypsum slurry to form at least part of a core of the gypsum panel, wherein the gypsum panel displays a 2-hour water absorption test weight increase of at least 10 weight percent less than an otherwise identical comparative panel containing no phosphate salt or polymer in its core.

Methods, systems, and devices, are developed for in-situ placement of a concrete mix that can have the thixotropy to hold vertical dimension without containment, while maintaining pliability to be pumped into place and manipulated to a desired shape, and can be combined with concrete set accelerators, allowing subsequent layers of this concrete mix to be continuously stacked in place to build tall walls and such without the use of forms. Concrete without these special properties is pumped toward the point of placement where it is modified by injecting and mixing, into that line of pumped concrete, an admixture containing thixotropes, thickeners and/or set accelerators or other modifiers to provide these properties and other improvements. This method allows conventional plant batching with commonly available constituent materials for batching an economical concrete that is delivered to a jobsite and then is pumped most of the way to a point of placement.

Methods, systems, and devices, are developed for in-situ placement of a concrete mix that can have the thixotropy to hold vertical dimension without containment, while maintaining pliability to be pumped into place and manipulated to a desired shape, and can be combined with concrete set accelerators, allowing subsequent layers of this concrete mix to be continuously stacked in place to build tall walls and such without the use of forms. Concrete without these special properties is pumped toward the point of placement where it is modified by injecting and mixing, into that line of pumped concrete, an admixture containing thixotropes, thickeners and/or set accelerators or other modifiers to provide these properties and other improvements. This method allows conventional plant batching with commonly available constituent materials for batching an economical concrete that is delivered to a jobsite and then is pumped most of the way to a point of placement.

A composite fireproof board has structure that includes, from top to bottom, a bottom layer, a lower reinforcement mesh layer, a middle layer, an upper reinforcement mesh layer, and a surface layer. The middle layer includes an organic frame and an inorganic fireproof material filled within the frame. The frame is provided with fixed grooves on edges adjacent to the fireproof material, and is further provided with through holes.

A composite fireproof board has structure that includes, from top to bottom, a bottom layer, a lower reinforcement mesh layer, a middle layer, an upper reinforcement mesh layer, and a surface layer. The middle layer includes an organic frame and an inorganic fireproof material filled within the frame. The frame is provided with fixed grooves on edges adjacent to the fireproof material, and is further provided with through holes.

A composite fireproof board has structure that includes, from top to bottom, a bottom layer, a lower reinforcement mesh layer, a middle layer, an upper reinforcement mesh layer, and a surface layer. The middle layer includes an organic frame and an inorganic fireproof material filled within the frame. The frame is provided with fixed grooves on edges adjacent to the fireproof material, and is further provided with through holes.

A composite fireproof board has structure that includes, from top to bottom, a bottom layer, a lower reinforcement mesh layer, a middle layer, an upper reinforcement mesh layer, and a surface layer. The middle layer includes an organic frame and an inorganic fireproof material filled within the frame. The frame is provided with fixed grooves on edges adjacent to the fireproof material, and is further provided with through holes.