Effects of accelerated corrosion on rebar bonding in steel fiber concrete

ABSTRACT

The implementation of steel fibers in concrete has received strong attention, for the possibility of significantly reducing steel bar’s consumption in reinforced concrete structures. However, a small number of articles is found on the durability of steel fiber concrete and the performance of anchorage length, when submitted to chloride ion attacks. Seeking to contribute to the better understanding of the subject, this paper presents results for 12 (twelve) prismatic samples (100x100x250) mm³. Each sample received a steel bar within 8 mm in diameter, and these were divided into 2 (two) equal groups, which only the first group was subjected to the modified immersion accelerated corrosion test, in order to evaluate the damage caused by the attack of chloride ions on both bars and steel fibers. Each group presented 3 (three) samples with 1% of steel fiber and another 3 (three) without fiber, and the anchorage lengths (l_b) vary between 100%, 75% and 50%, as recommended by Brazilian standard NBR 6118. It was verified that there was no compromise related to the adhesion’s loss between steel bar and concrete substrate, when reduced the (l_b) by 25% and guarantees functionality, which can result in cost reduction. In addition, the corrosion resulted in a loss of 50% of the value of the maximum pullout load.

Key-words
Anchorage length; Steel fiber; Adhesion; Corrosion