THERMAL SIMULATION OF THE EFFECT OF CLIMATE CHANGE ON DUCTILE-BRITTLE TRANSITION PROPERTY OF HYS REINFORCEMENT STEEL RODS AND CONSEQUENT CORRELATION TO COLLAPSE BUILDINGS IN NIGERIA.

Abstract

In the year 2024 alone close to 200 incidences of building collapse occurred across Nigeria. Cities like Lagos, Abuja, Benin, Port-Harcourt were constantly plagued. Apart from material losses, human lives were involved in these incidences and the question was why this alarming rate of building collapses. Failure investigations were mainly focused on geotechnical factors, quality of building materials, quality of workers and professionals involved. No consideration was given to climate change and environmental factors. Could there be an environmental dimension to this menace of incessant building collapse in Nigeria? This question informs the reason for this work ‘’Simulation of the Effect of Climate Change on Ductile-Brittle Transition Property of Reinforcement Steel Rods and Consequent Correlation to Collapse Buildings in Nigeria’’. The work was carried out by collecting test samples of HYS reinforcement steel rods from three different mini mills in Nigeria. The samples were prepared into test specimens using lathe and other cutting equipment for impact test on impact testing equipment, hardness test on Brinell hardness tester, and tensile test on Universal Strength testing machine. Other tests carried out on the samples were chemical composition analysis and microstructure analysis, which were done using Spectro-Lab and SEM. To simulate the effect of climate change on the steel reinforcement; tests were carried out on the 3 different samples under freezing conditions, 27oC, and 40oC. These represented the extreme weather conditions experienced in recent times. The result showed that as the temperature was increased the impact energy values required for fracturing the 3 different specimens were also increasing and as the temperature was decreasing down to freezing region the impact energy required for fracturing the 3 different specimens was also decreasing. The impact values of the 3 specimens (C, D, & F) were lower under freezing conditions than at 27oC. Equally the result showed that the impact energy value of the 3 specimens (C, D &F) was higher at 40oC. The result showed that for all the mechanical properties tested, they were affected by the variation in temperature. These reinforcement rods are used in buildings and if their properties are affected by temperature which is associated with the environment it therefore means there is a correlation between climate change and collapse buildings in Nigeria. The most dangerous temperature on the reinforcement steel rods been the freezing range. Steel is associated with ductile-brittle transition and when the threshold value is exceeded sudden building collapse can occur since the failure becomes brittle in nature. The values of impact energy, hardness, yield and ultimate tensile strength were all low under the freezing range.