One of the key drivers for the adoption of Alkali Activated Material (AAM) over recent years is the reduction in CO2 emissions compared to Portland Cement and it is well known that AAM based concretes have superior strength characteristics in comparison to Portland Cement based concretes. However, many consider the durability of AAMs to be an unproven issue and therefore in the past decade many tests and investigations like this one have been undertaken to obtain a better understanding of the durability of AAM based concretes. The purpose of this paper is to assess the carbonation resistance of AAM concretes based on Ground Granulated Blast-furnace Slag (GGBS) and Pulverised Fly-Ash (PFA). The carbonation depth and strength change of four mix designs has been measured; two based on GGBS and two based on a blend of GGBS and PFA. A combination of both Sodium Hydroxide and Sodium Silicate was used as activator solution for various mix designs. This was completed as part of a wider study of AAM based concretes properties and overall durability. For investigating the effect of differing percentages of relative humidity on the carbonation of AAM concretes under accelerated condition, a constant CO2 level of 5% which is greatly elevated from the atmospheric level, as well as a constant temperature of 20°C was considered. Then the carbonation depths and strength changes of all mixes were tested at 50%, 65%, 75% and 85% humidity levels.
|Title of host publication||Proceedings of the 37th Cement and Concrete Science Conference|
|Number of pages||4|
|Publication status||Published - 1 Sep 2017|
Bibliographical noteProceedings of the 37th Cement and Concrete Science Conference, Bai, Y., Zhang, M., Shi, S. (eds.), UCL; 37th Annual Cement and Concrete Science Conference, 37CCSC ; Conference date: 11-09-2017 Through 12-09-2017
- Alkali activated binders/concretes