A hardened cementitious composite produced using conventional mixing techniques, including a microsilica-cement mixture and randomly distributed discontinuous polyamide fibers is described. Other mix ingredients used in forming the composite are superplasticizer, water and possibly aggregates and fly ash substituting for part of the Portland cement. The microsilica particles are essential in dispersing the fibers during the regular mixing, and in enhancing the fiber-cement interfacial bond. Microsilica also reduces the alkalinity of the matrix and helps in increasing the durability of polyamide fibers in the alkaline environment of cement. With their close spacing and superior bond to the matrix of the composite, the polyamide fibers are highly effective in increasing the ultimate tensile and flexural strength and in improving the ductility and toughness of the material.
A method for upgrading existing nylon fibers comprising the steps of (a) impregnating the existing nylon fibers with a chemical for obtaining impregnated nylon fibers; (b) drawing the impregnated nylon fibers for obtaining drawn nylon fibers; and (c) drying the drawn nylon fibers for obtaining upgraded nylon fibers. An upgraded nylon fiber, derived from an existing nylon fiber by the method. A nylon fiber reinforced hardened cementitious composite comprising a hardened cementitious matrix, the cementitious matrix including staples of textile or non-textile (technical) upgraded nylon fibers. In both cases the fibers are preferably upgraded using the method. A method for manufacturing a nylon fiber reinforced hardened cementitious composite. The method comprising the steps of (a) preparing a mix including a cementitious material, staples of upgraded nylon fibers and/or textile nylon fibers and an activating material (e.g., water) for activating said cementitious material to form a hardened cementitious matrix; (b) placing the mix; and (c) allowing the mix to harden.
This invention relates to a heat insulator and a structure using the heat insulator and aims to provide a heat insulator which can be subject to a dry application using the heat insulator in the molded board or a wet application, having characteristics similar to those of a conventional inorganic heat insulator and a high strength which has not been provided before and to provide a structure using the above heat insulator. The heat insulator of this invention is prepared by mixing 3 to 50 parts by weight of synthetic resin emulsion in solid content equivalency, 1 to 20 parts by weight of organic microballoon, 0.3 to 5 parts by weight of carbon fiber and 10 to 200 parts by weight of inorganic microballoon with 100 parts by weight of cement. And the heat insulator of this invention is prepared by mixing 3 to 50 parts by weight of synthetic resin emulsion in solid content equivalency, 1 to 20 parts by weight of organic microballoon and 0.3 to 5 parts by weight of carbon fiber with 100 parts by weight of cement.
A method is disclosed for improving the properties of polymer fibers incorporated into upcured concrete. A wetting agent is incorporated into the molten polymer prior to extrusion into fibers in order to render the fibers durably wettable.
Purposeful addition of crack-initiating voids in the form of low tensile strength particulates, particulates having low matrix interaction, or gas bubbles formed by chemical reaction, in a size range of 0.5 mm to about 5 mm, and preferably of a size commensurate with or larger than naturally occurring crack-initiating gaseous voids, to fiber-reinforced strain hardening cementitious composites generates controlled and uniform cracking which increases strain hardening behavior in conventionally dense cementitious compositions.
A fiber-reinforced concrete-like material product includes a plurality of fibers containing an effective amount of at least one antimicrobial agent to inhibit organisms and protect the concrete from biological attack. Preferably, the antimicrobial agents are added to the fibers prior to the fibers being dispersed in the concrete. Such a concrete product containing antimicrobial-enhanced fibers simultaneously inhibits organisms from biological attack, reduces plastic shrinkage cracking of the concrete and improve post-peak flexural strength of the concrete.
