This article presents the experimental results on accelerated carbonation‐induced corrosion and related durability properties such as AC impendence, half‐cell potential, water permeability, and volume of permeable voids test of concrete made with high‐volume Class F fly ash (FA). Concrete specimens were prepared by substituting ordinary portland cement with FA at varying replacement levels (0–70%). High‐volume FA concrete shows the continuous gain in the compressive strength and ultrasonic pulse velocity over a period of 365 days. The durability properties of concrete made with FA up to 50% shows the significant improvement. The scanning electron microscopy photomicrographs also support the findings and shows that the replacement of cement with FA densifies the concrete matrix due to the formation of more calcium silicate hydrate gels.

The results of an experimental study on the effect of the partial replacement of ordinary Portland cement with nanosilica (NS) on the mechanical and durability properties of concrete are presented. Concrete mixes were made with varying NS contents at a constant water/binder ratio of 0·40. The test results demonstrated that the inclusion of 3% NS as a partial replacement of cement enhanced the mechanical properties and reduced the water penetration depth and water absorption of the concrete, resulting in overall improved performance. Compared with normal concrete, the water penetration depth and water absorption of the NS concrete was reduced by 42·85% and 36·84%, respectively. The carbonation depth was also reduced as a result of cement replacement with NS, leading to enhanced concrete durability. These enhancements in the mechanical and durability properties were mainly due to the high fineness and increased pozzolanic activity of the added NS.

This paper describes an experimental investigation on the carbonation of Portland pozzolan cement (PPC) concrete with marble dust (MD). The five PPC concrete mixes containing MD (up to 20%) were prepared with three different water–cement ratios (0·5, 0·6 and 0·7). All the concrete cube specimens were exposed to natural atmospheric carbonation after 28 d of moist curing. It was observed that the use of 10% MD enhanced the compressive strength of concrete and the carbonation coefficient decreased with an increase in MD content.

This research reports the experimental outcomes of potentiodynamic analysis of the steel reinforcement in carbonated and uncarbonated high-volume fly-ash concrete powder solution extracts (CPSE). Different percentages of fly-ash content have been used to form a high-volume fly-ash concrete (0%, 20%, 40%, 50%, 60%, and 70%) with three different types of steel reinforced. Three different water-to-binder ratios (0.35, 0.40, and 0.45) have been used to form the reinforced concrete. The different zones of corrosion were observed through the anodic polarization curve, which was obtained through the potentiodynamic linear sweep test. It has indeed been demonstrated that concrete with up to 50% fly ash shows better resistance against carbonation, as compared to Ordinary Portland Cement (OPC) concrete. Fully active anodic polarization curve is obtained for carbonated concrete. Corrosion-resistant steel performed better as compared to TATA TMT and SISCON TMT types of steel. The ANOVA also verifies the experimental observation, which shows that the content of fly ash and types of steel decide the extent of corrosion in the concrete. It has also been observed that the interaction between the fly-ash content and water-binder proportion and also the interaction between fly ash and the type of steel show the strong effect on the corrosion activity, which decides the extent of different zones of corrosion.

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