Synthetic fibers and cementitious systems including same

Abstract

The present invention discloses novel fibers for use as secondary reinforcement materials in cementitious composites, which fibers are effective in preventing cracking far better than prior art fibers. Also disclosed are methods of producing the fibers and methods for producing cementitious composite containing the fibers.

1 - 54 . (canceled)  
   
   
       55 . A fiber reinforced cementitious composite comprising a hardened cementitious matrix, said matrix including staples of low orientation precursor nylon fibers being characterized by an average birefringence value greater than 0.0350, but less than 0.0440, an average modulus greater than 10 gram/denier, but less than 25 gram/denier, an average tenacity greater than 2.5 gram/denier, but less than 3.4 gram/denier, and an average elongation capacity greater than 46%, but less than 100%.  
   
   
       56 . The cementitious composite of  claim 55 , wherein said fibers are impregnated with a chemical selected so as to obtain upgraded fibers characterized by increased chemical stability.  
   
   
       57 . The cementitious composite of  claim 56 , wherein said upgraded fibers acquire superior basic hydrolysis resistance.  
   
   
       58 . The cementitious composite of  claim 55 , wherein said fibers are crimped fibers.  
   
   
       59 . The cementitious composite  56 , wherein said chemical is selected from the group consisting of a salt that undergoes acid hydrolysis, benzene phosphonic acid, a manganese salt, a hindered phenol photo stabilizer, a hindered amine photo stabilizer, a phosphorous compound for ultraviolet stabilization, a phosphorous, amino and phenolic based antioxidants and copper iodide, copper acetate, potassium iodide, potassium bromide, zinc chloride and microsilica.  
   
   
       60 . The cementitious composite of  claim 55 , wherein said fibers include a nylon substance selected from the group consisting of nylon 6.6, nylon 6, copolymer nylon 6.6,6, copolymer nylon 6.6,6. TA and nylon 6.4.  
   
   
       61 . A method of manufacturing a reinforced hardened cementitious composite comprising the steps of: (a) providing components of a cementitious matrix including a cementitious substance, water and staples of low orientation precursor nylon fibers being characterized by an average birefringence value greater than 0.0350, but less than 0.0440, an average modulus greater than 10 gram/denier, but less than 25 gram/denier, an average tenacity greater than 2.5 gram/denier, but less than 3.4 gram/denier, and an average elongation capacity greater than 46%, but less than 100%; (b) mixing said components until said fibers become well dispersed therein; and (c) hardening said matrix.  
   
   
       62 . The method of  claim 61 , wherein said fibers are impregnated with a chemical selected so as to obtain upgraded fibers characterized by increased chemical stability.  
   
   
       63 . The method of  claim 62 , wherein said upgraded fibers acquire superior basic hydrolysis resistance.  
   
   
       64 . The method of  claim 61 , wherein said fibers are crimped fibers.  
   
   
       65 . The method of  claim 62 , wherein said chemical is selected from the group consisting of a salt that undergoes acid hydrolysis, benzene phosphonic acid, a manganese salt, a hindered phenol photo stabilizer, a hindered amine photo stabilizer, a phosphorous compound for ultraviolet stabilization, a phosphorous, amino and phenolic based antioxidants and copper iodide, copper acetate, potassium iodide, potassium bromide, zinc chloride and microsilica.  
   
   
       66 . The method of  claim 61 , wherein said fibers include a nylon substance selected from the group consisting of nylon 6.6, nylon 6, copolymer nylon 6.6,6, copolymer nylon 6.6,6. TA and nylon 6.4.  
   
   
       67 - 121 . (canceled)