Combined use of silica fume and methylcellulose as admixtures in concrete for increasing the bond strength between concrete and steel rebar

The combined use of silica fume (15% by weight of cement) and methylcellulose (0.4% by weight of cement) as admixtures was found to give concrete that exhibited high bond strength to steel rebar, in addition to previously reported high tensile modulus, tensile ductility, flexural strength, and flexural toughness. The bond strength attained was essentially the same as that attained by using latex (20% by weight of cement) as admixture. The bond strength attained was higher than that attained by using either silica fume or methylcellulose as admixture. Latex in combination with silica fume did not work, due to low workability. M ethyleelluose in combination with silica fume was effective, due to silica fume's increasing of the matrix modulus and methylcellulose's promotion of adhesion.