INFLUENCE OF CEMENT TYPE AND TEMPERATURE ON THE RATE OF CORROSION OF STEEL IN CONCRETE EXPOSED TO CARBONATION

摘要

This paper presents the results of laboratory investigation on the influence of cement type and temperature on the rate of corrosion of steel in concrete exposed to accelerated carbonation (15 percent CO_2 concentration). In this study, reinforced concrete specimens (10 cm X 10 cm X 40 cm) having a water/cement ratio of 0.55, exposed at different temperature conditions (20 deg C, 30 deg C and 40 deg C) were investigated. Measurement of carbonation depth, void ratio, oxygen permeability, and corrosion rate were performed in the laboratory in order to assess the influence of cement type and temperature on the mechanism of steel corrosion in concrete. The test results show that concrete containing Ordinary Portland Cement had better corrosion resistance at lower temperature than Blast Furnace Slag Cement. On the other hand, BFSC concrete performs better at higher temperature (30 deg C and 40 deg C) especially when exposed over a longer period of time. In general, corrosion rate in the specimens increased with temperature. This was consistent with the theoretical expectation that corrosion rate increases with temperature. Moreover, it was confirmed that the natural logarithm of total corrosion rate is linearly related to the reciprocal of the absolute temperature which is in agreement with the Arhennius principle.