In the present paper, an experimental work was carried out to study the effect of ground waste tire
rubber addition on the mechanical properties and impact resistance of normal strength concrete
(NSC) with and without silica fume. Three different volume ratios of cnunb rubber (lo%, 20%,
and 30%) were used as a partial replacement of sand. Two different sizes of cylinders were tested
, under indirect tension test to study the size effect. Impact compression according to ACI
Committee 544's repeated drop-weight impact test was carried out on discs of 150 mm diameter
, .
' ana 63 mm height. Test results showed that, the replacement of fine aggregate by 10% crumb
, . rubber caused a small decrease in concrete compressive strength. The presence of crumb rubber of
:,. small size in concrete increased its resistance to crack initiation under impact load. Tbe rubber of
small sue bas no varticle brid.eiua effect, hence, the mode of failure of rubberized concrete under
static and impact ~ompression&a~ the s&e as that of plain concrete. The ACI impact test failed to
differentiate between the impact resistance of rubberized concretes with different rubber contents.