Comparative Analysis of Global Standards in Accelerated Carbonation Testing of Concrete

Abstract

One of the main factors of corrosion affecting the durability of concrete is carbonation. Testing concrete under natural carbonation conditions is time-consuming, leading to the development of accelerated carbonation tests. These tests involve exposing specimens to high concentrations of CO₂ in controlled chambers, allowing for the prediction of concrete's resistance to carbonation within a shorter timeframe. There are many standards for this kind of test globally, which share the same principle but differ in methodologies. This diversity in standards underscores the need to study and compare them to identify the similarities, differences, and reasons for these variations in accelerated carbonation tests worldwide. This study was conducted by comparing 12 different standards from various regions, collectively representing approximately 38.33% of the world’s population. The research focuses on key testing parameters, including the preconditioning regime, specimen type and surface area, CO₂ concentrations, environmental conditions, exposure durations, and measurement techniques. The results revealed significant variations across all parameters, primarily due to differences in climatic conditions and testing objectives. Additionally, a correlation was observed between CO₂ concentration and concrete surface area across different standards. The study also noted that standards specifying higher CO₂ concentrations tend to have shorter test durations compared to those with lower CO₂ concentrations, aiming to accelerate the testing process. Furthermore, it concludes by recommending the ISO standard as a potential benchmark for accelerated carbonation testing, due to its adaptability to diverse climatic conditions and its potential to harmonize global testing practices.