Advanced fiber reinforced concrete mix designs

Abstract

A concrete mix having sand, fine aggregates, binder, fibers, and various admixtures is provided. The mix has a consistency from S2 to SF3, a compressive strength in the range of 30-60 MPa and a ductility represented by fc, ffl, fR1 and fR3 values, wherein the concrete mix contains at least 390 Kg of binder, the concrete mix has a paste volume of 300-600 liters, the concrete mix contains at least two systems of fibers and a general admixture system that is composed of at least 2 sub-admixture systems.

1 . A concrete mix comprising sand, fine aggregates, binder, fibers, and various admixtures, having a consistency from S2 to SF3, a compressive strength in the range of 30-60 Mpa and a ductility represented by the following values:
 30<fc<60 MPa   3<ffl<8 Mpa   3<fR1<8Mpa   2.5<fR3<8 MPa   wherein the concrete mix contains at least 390 Kg of binder, the concrete mix comprises a paste volume of 300-600 liters, the concrete mix contains at least two systems of fibers A and B, the fibers system A consists of metallic fibers with a dosage of 25-100 kg/m3 with respect to the concrete mix and mechanical resistance of at least 1100 MPa, the fibers system B have a dosage of 0.2%-0-9% by m 3  of the concrete mix, the concrete mix contains a general admixture system that is composed of at least 2 sub-admixture systems I and II, wherein the first Admixture system I comprises at least 2 polycarboxylic acid co-polymers (PCE), a strong water reducer PCE and a workability retention PCE, wherein the second Admixture system II is a stabilizer obtained from a compound selected from the group consisting of modified cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, natural starch, modified starch, branched modified starch, naturals gums, Xanthan gum, fine silica, colloidal silica, silica fume and any combination thereof.   
     
     
         2 . Concrete mix according to  claim 1 , further comprising coarse aggregates. 
     
     
         3 . Concrete mix according to  claim 1 , wherein the dosing of the Admixture system I is of 0.5-5% weight percent with respect to the binder content and the dosing of the admixture system II is of 0.1-2% weight percent with respect to the binder. 
     
     
         4 . Concrete mix according to  claim 1 , wherein the dosing of the Admixture system I is of 0.1-1% weight percent with respect to the binder content and the dosing of the admixture system II is of 0.1-0.5% weight percent with respect to the binder. 
     
     
         5 . Concrete mix according to  claim 1 , wherein the concrete mix comprises an admixture system III, wherein the third Admixture system III is obtained from a compound selected from the group consisting of cellulose microfibers, synthetic waxes, natural waxes, superabsorbing polymers, starch crosslinked polymers, acrylate crosslinked polymers, hexylene glycol (2-Methyl-2,4-pentanediol) and any combination thereof and the dosage of the admixture system III is of 0.3-6 weight percent with respect to the binder. 
     
     
         6 . Concrete mix according to  claim 1 , wherein fibers system C, comprising synthetic fibers, is added to the concrete mix. 
     
     
         7 . Concrete mix according to  claim 6 , wherein the dosage of fibers system C is of 0.02% to 2% volume with respect to the concrete. 
     
     
         8 . Concrete mix according to  claim 2 , wherein a part of the sand or the fine aggregates or the coarse aggregates are substituted by lightweight aggregates selected from the group consisting of expanded glass, expanded clay, pumice and expanded shale. 
     
     
         9 . Concrete mix according to  claim 8 , wherein the substitution rate for all aggregates (sand or/and fine or/and coarse aggregates) is at least 30% in volume.