Corrosion rate of carbon steel in carbonated concrete made with different supplementary cementitious materials

Abstract

Carbonation-induced corrosion limits the durability of reinforced concrete structures exposed in urban environments. In these exposure conditions, the propagation phase of corrosion can be an important part of the service life and, hence the knowledge of the corrosion rate is essential for the design. However, data regarding the corrosion rate in carbonated concrete are scarce and mainly refer to Portland cement concrete. This paper reports the corrosion rate and corrosion potential of steel bars embedded in concretes with different binders and water/binder ratios, exposed both outdoor in unsheltered conditions and in laboratory conditions characterised by different temperatures and relative humidities. Concrete resistivity at different depths is also reported and correlations among these parameters are discussed. Corrosion potential, corrosion rate and concrete resistivity were strongly influenced by the relative humidity, while temperature played an important role only at high relative humidity. Steel in Portland cement concrete showed the lowest corrosion rate.

Service life of reinforced concrete structures made with blended cements and exposed in urban environment

“…i corr ), in outdoor unsheltered exposure conditions, and a SD of 0.25 times the mean value (upper and lower limits equal to 0.1 and 15 μm/year for all the types of binder, in agreement with the minimum and maximum values detected outdoor, were considered). Although these data were obtained on concretes with water/binder ratio equal to 0.61, it was observed that the water/binder ratio did not strongly affect the corrosion rate 25 . P lim was described by means of a normal distribution with a mean value and a SD respectively equal to 100 and 30 μm, considering as limit state the concrete cracking.…”

“…Although these data were obtained on concretes with water/binder ratio equal to 0.61, it was observed that the water/binder ratio did not strongly affect the corrosion rate. 25 P lim was described by means of a normal distribution with a mean value and a SD respectively equal to 100 and 30 μm, considering as limit state the concrete cracking. Table 2 summarizes the values selected for the different parameters.…”

Influência do agregado reciclado na durabilidade do concreto armado frente a corrosão de armadura desencadeada por carbonatação acelerada

“…Estes resultados indicam que o ensaio de potencial de corrosão está correto, uma vez que com exceção do traço com 50% de agregado reciclado, se manteve na zona de incerteza e ao fazer as leituras da profundidade, ficou evidente que em nenhum corpo de prova submetido à carbonatação acelerada atingiu as barras, desencadeando a corrosão das mesmas. Assim, concretos feitos com agregados reciclados podem apresentar profundidade de carbonatação 2,5 vezes maior que os concretos convencionais e ainda segundo o autor, concretos feitos com 100% de RCC esta diferença pode ser de 8,7 vezes devido a porosidade do material (ZHAO et al, 2020;LOLLINI;RADAELLI, 2021).…”