Combined DRI and μXRF for Quantitative Characterization of Damage in ASR-Affected Concrete: A Proof-Of-Concept Investigation

Much interest surrounds the ability to quantitatively characterize alkali silica reaction (ASR) damage in concrete, particularly as it relates to the progression of ASR and its resulting damage pattern. Characterization methods which can provide both spatial and compositional information, then, can provide insights into the extent and progression of ASR damage in affected concrete. Micro x-ray fluorescence (µXRF) allows elemental mapping and quantification based on x-ray excitation, with spatial resolution approaching 20 µm, but to date only limited work has been published using this technique for ASR investigations. The Damage Rating Index (DRI) has been used as a semi-qualitative method using weighted scoring of concrete damage in 1 cm2 grid areas using a stereoscope to visually quantify the observed damage. Both techniques operate on similar scales (e.g., can be performed on concretes or mortars), and it is believed they can complement each other in the types of provided information. This paper is a first step in evaluating the potential benefit in combining both µXRF and DRI to investigate ASR-affected concrete with the goal of comprehensively quantifying damage in ASR-affected concrete by coupling damage features from DRI to µXRF elemental mapping. DRI and µXRF were both performed on cores retrieved from ASR-affected concrete highway (“Jersey”) barriers. Using the same referenced areas, information provided from DRI and µXRF scans are presented to showcase potential for a more comprehensive characterization of damage.