10 Pages

Experimental simulation of surface cracking in concrete structures affected by AAR

G. Nery & P. Helene D. Cusson & J.C. Margeson

ABSTRACT: Alkali-aggregate reaction (AAR) is a slow expansive reaction that occurs in concrete between the alkali in cement and reactive aggregates, leading to spalling and strength loss of the concrete. This reaction takes years to develop and the speed of reaction depends on several material and environmental parameters. In order to develop and test corrective solutions to this problem in a reasonable laboratory timeframe, it is possible to accelerate AAR by using extremely reactive materials under carefully controlled environments. This paper presents a new approach that was developed to simulate AAR-like expansion and random surface cracking in just a few days without the need for a controlled environment. After testing different approaches, the successful approach consisted of the combined use of pervious concrete and expansive cement paste. It was found that the cracking patterns obtained on cylindrical and prismatic concrete specimens were very similar to those found in real structures affected by AAR.