Experience of using the prTS 12390-12 accelerated carbonation test to assess the relative performance of concrete

Abstract

This paper reports data on the use of the prTS 12390-12 accelerated carbonation test (reference method) over the past two decades and shows that accelerated carbonation testing is a suitable technique for ranking concretes in their carbonation resistance. Testing at 5, 7 and 10 weeks provides the optimum solution that minimises the risk of incorrect ranking of different constituent materials. Analysis of data from previous studies also shows that the reference test conditions of a partial pressure of 4% carbon dioxide are a suitable level which allows sufficient carbonation to take place for accurate depth measurement while the preconditioning period of 28 days standard followed by 2 weeks drying in laboratory air did not disadvantage pozzolanic and similar type cements.

Corrosion of reinforcement in concrete containing wet-stored fly ash

“…Several studies have used or examined the effects of accelerated testing on cement/fly ash systems (e.g. [27,30,43]). Research suggests that ettringite, aluminates and portlandite carbonate independently of exposure concentration [44].…”

“…Research suggests that ettringite, aluminates and portlandite carbonate independently of exposure concentration [44]. However, at higher CO2 levels, the ratio of reaction products can be different to those formed when these are lower [30] and variations in porosity [44], which may change between cement combinations [43] have been noted. However, there appears to be no evidence [30] that these have any significant effect on overall carbonation rate.…”

“…However, at higher CO2 levels, the ratio of reaction products can be different to those formed when these are lower [30] and variations in porosity [44], which may change between cement combinations [43] have been noted. However, there appears to be no evidence [30] that these have any significant effect on overall carbonation rate. Given the reactivity between CSH products and CO2 may change for different additions, it has been suggested that accelerated tests are best restricted to comparisons where these are the same [45], which was the approach followed in the current study.…”

“…The influence of fly ash on chloride ingress and carbonation, and resulting reinforcement corrosion in concrete, have been examined in many investigations over the last few decades, given their damaging effects on structures [e.g. [20][21][22][23][24][25][26][27][28][29][30][31]. The influence of fly ash in concrete on these processes, compared to that of Portland cement (PC), is mainly due to physical and chemical effects including, changes in microstructure, lime consumption and binding capacity.…”

Durability Properties and Microstructure of Ground Granulated Blast Furnace Slag Cement Concrete

“…Therefore, partial replacement of PC with GGBS can significantly reduce the risk of sulfate attack, alkali-silica reactions and chloride penetration and increase compressive strength (Güneyisi and Gesoglu 2008;Hadj-Sadok et al 2010;Nazari and Riahi 2011;Shi et al 2011Shi et al , 2012Teng et al 2013). However, it may reduce the resistance of the concrete against carbonation (Harrison et al 2012;Shi et al 2009;Jia et al 2011).…”