Project N.7
Title:
Mitigating carbonation and
other forms of chemical attack
on AAM
Objectives
For AAM concretes to be used at scale in industrial practice, it is essential to develop the capability to understand and enhance their durability. The core aim of this ESR project is to develop a methodology by which carbonation attack on AAMs can be mitigated, as this has been identified as a potentially problematic mode of degradation of these materials in several relevant service environments. To achieve this aim, the following objectives are defined:
| 1) | Validate the relationship between accelerated carbonation testing (1% CO2 and 65% RH proposed as test conditions, following the work of RILEM TC 247-DTA) and carbonation under natural conditions, from both mechanic and kinetic viewpoints, for AAMs |
| 2) | Define the effect of carbonation on microstructure and chemistry (specifically pH) of AAM concretes, with a specific view toward defining influences on steel corrosion. This will involve links with ESRs 2, 3 and 8 around transport phenomena as carbonation-induced microstructural alteration is expected to have a significant impact on chloride transport, and ESRs 9 and 12 as carbonation-induced pH reduction may also reduce the critical chloride threshold for steel corrosion within these concretes, even if the carbonation itself is not sufficient to induce corrosion. |
Develop initial work with layered double hydroxides as ‘smart’ mineral admixtures (e.g. Ke et al., Cem Concr Res 81(2016):24-37) into a technically and economically feasible route to mitigation of carbonation-related degradation of AAM concretes, making particular use of the ability of layered double hydroxide structures to be tailored for uptake of carbonate and/or chloride anions.
Expected Results
Researcher trained to the highest international standard in innovative and world-leading research, and connected to other leading organisations. In a technical sense, the ESR will provide new insight into the influence of carbonation on AAM concretes, and ways in which this can be mitigated and controlled to enable the provision of AAM materials with excellent properties in service.