Environmental degradation of 30 to 50 years old reinforced concrete structures in Qatari climate

Abstract

This paper presents the results of a field survey carried out on three reinforced concrete (RC) structures built respectively in 1960's 1970's and 1980's to determine the main load (environmental) and resistance (concrete quality, clear cover etc.) factors in Qatari infrastructure. The environmental load factors such as carbonation depths and chloride concentration profiles in columns, beams and slabs were determined by testing concrete core samples. To determine the pertinent resistance factors, the concrete resistivity to electrical charge, sorpitivity and rapid chloride permeability were measured. In most of the structural members, the chloride threshold for steel depassivation was surpassed and the carbonation had reached the steel surface. The spalling of concrete cover was observed with severe corrosion damage to reinforcing bars. This study will help understand the degradation phenomena of RC structures and the results will help establish the input parameters for chloride diffusion and carbonation models in aggressive environmental conditions.