Reduction of alkalinity of concrete due to the diffusivity of carbon dioxide (CO2) and concrete carbonation is one of the major issues influencing the durability of reinforced concrete structures. Most of the previous studies have concentrated on the un-cracked / unloaded concrete although it has been acknowledged that structural cracks in concrete have an impact on the CO2 diffusivity and carbonation - induced reinforcement corrosion as well as service life of concrete structures. Hence, this article aims to investigate the effect of cracks (produced by loading) in concrete exposed to the CO2 environment condition, on the alkalinity level (apparent pH) and carbonation depth in concrete. Accelerated environmental test programme has been used on concrete prisms with four different crack widths. The depth of carbonation (DoC), apparent pH, and consumption of alkalinity (OH-) is investigated in accordance with the BS EN13295:2004  and the method proposed by Mc Polin et al. . The influence of replacing ordinary Portland cement (OPC) by pulverized fuel ash (PFA) and ground granulated blast furnace slag (GGBS) on the CO2 diffusivity in cracked concrete, is also analyzed and presented in this paper. The results have shown a strong relationship between DoC and the alkalinity level (consumed OH-) and pH of concrete structures. There is a considerable impact of crack width on the reduction in concrete alkalinity. The results also demonstrate a significant increase in consumption of OH- and reduction in pH owing to the addition of supplementary materials in the samples.
|Number of pages
|Published - 12 Jun 2019
|EuroCoalAsh2019 - University of Dundee, Dundee, United Kingdom
Duration: 10 Jun 2019 → 12 Jun 2019
|10/06/19 → 12/06/19