Investigation of conformity of Reinforcing Steel Bars Usedin Kinshasa Construction Industry.

ABSTRACT
An investigation study was carried out to ascertain the level of conformity with the standards for
reinforcing steel bars used in the construction industry of Kinshasa. Thus, the British Standard BS 4449: 1997
was used. Reinforcing steel bars found in Kinshasa market, then tested, came from eleven companies. Tensile
test was conducted on sixty-five samples selected from the available and most used reinforcing steel bars. Ten
specimens were used for every company diameter size.
After testing, only sixteen over sixty-five specimens (25%) satisfied fully the standard requirements.
None of the companies did fully comply with all code requirements. In addition, in respect to the measured
diameter most of specimens failed to satisfy the nominal diameter required values. For characteristic strength
criteria, only nineteen over sixty-five specimens complete the code requirements. However, all of the reinforcing
steel bar samples complied with the minimum ultimate to yield strength ratio as specified by the code provisions.
Fifty-tree over sixty-five specimens met the minimum code requirements on elongation criteria. Nevertheless,
specimens from 6mm diameter mostly failed. Therefore, steel bars from Kinshasa market should not be used for
the reinforcement of structural concrete without first subjecting them appropriately to tensile test, and a constant
check by a Government agency is recommended