"Portland cement is generally used, sometimes blended with a . The filler... is usually a well-graded sand capable of passing a 2.36 mm (No. 8) sieve. However, depending upon the... reinforcing material (mesh opening, distribution, etc.), a mortar containing some small-size gravel may be used. ...Addition of short and discrete fibers of different types favorably affects the control of cracking and the capacity... to resist tensile loads. ...[R]elatively short and slender (l/d = 100) steel fibers may be randomly distributed in hydraulic cement mortars... the overall effect being to increase tensile strength and improve the shear resistance..."