Analysis of the ductility of reinforcement structural steel rods from some local mini mills in Nigeria using theoretical and statistical approach

Abstract

Analysis of the ductility of reinforcement structural steel rods from some local mini mills in Nigeria using theoretical and statistical approach has been carried out. Ductility is one parameter required of reinforcement structural steels; it prevents sudden failure of reinforced concrete structures. In this work samples were collected from four different mini mills and subjected to tensile test. The initial gauge value of the test specimens was noted. The failed test specimens were then joined together individually to measure the final length at failure and to calculate the % elongation at failure. Stress –strain plots were made to determine the pattern of deformation and failure. The results show that all the specimens have stress-strain curves typical of ductile materials. The % elongation at failure of specimen 3 was the highest at 15.37, the other specimens too all had reasonable % elongation; meaning they are ductile materials. The statistical approach used in the analysis of the work produced results that completely agreed with the theoretical analysis of the work. The statistical analysis used included the use of expected values calculation to select the best ductile specimen, the use of bar chart to show the specimen with the highest % elongation and the one with the lowest value of % elongation, the use of to test if all the specimens have the same % elongation or ductility, and the use of spearman rank correlation coefficient to test if the % elongation is associated with the maximum loading of the specimens. In conclusion the work has highlighted the need for structural reinforcement steel bars to have reasonable ductility in order to avoid sudden failures associated with brittle materials, when used in buildings and other concrete structures.