Bond strength behavior for deformed steel rebar embedded in self-compacting concrete incorporating nano-silica

The present research studies the nano particles influence on the strength of the bond between the reinforcing bar and self-compacting concrete through experimental work. Twenty-one push-out specimens were examined in experimental program. Such investigation evaluates the nano silica influence in three percentages (3%, 4.5%, and 6%) by weight of cement. The age of concrete, embedded length of steel bar, percentage of nano silica, concrete cover and size of rebar, are the main variables in experimental work. The modes of failure, namely the behavior of bond-slip and ultimate bond strength, were discussed. Analysis of test results indicate that compared with conventional concrete the bond strength in concrete is increased by 9.2%, 13.1%, and 12.4% when adding nano-silica by (3, 4.5 and 6%), respectively. As in conventional concrete, the bonding strength increases with the age of the concrete. In addition, the increase of concrete cover increases the bond strength. On the other hand, the increase of the embedded length, and size of rebar decreases the bond strength in self- compacting concrete (SCC) incorporating nano-silica. Modes of failure in reinforcing bar embedded in self-compacting concrete incorporating nano-silica were the push-out and splitting failure. This was similar to the case in conventional concrete.