Establishing Two ASR Exposure Sites in Switzerland – Approach and Goals

Alkali-silica-reaction (ASR) exposure sites allow studying the behavior of concrete with reactive aggregates in natural exposure on the long term. As such, the exposed specimens can show both the kinetics and magnitude of concrete expansion and the effectiveness of ASR-suppressing measures. Moreover, the combination with accelerated laboratory tests makes it possible to validate the latter. Recently, two exposure sites have been established in Switzerland, one at low elevation in the Midlands and the other one in the Alps at an altitude of 2200 m above sea level. The goal of the present project is to validate the concrete prism test (CPT) and the residual expansion test (RET) used to assess the durability of a structural concrete. Concrete mix designs mirroring the current Swiss market for engineering structures and dam concrete are used. 40 concrete mixtures are produced in total. So far, the CPT has been conducted and the exposure of the cubes at the two sites for an intended duration of 15 years has started. After three years cores will be taken from selected cubes to perform the RET.