Development and commercialization of self-healing concrete is hampered due to a lack of standardized test methods. Six inter-laboratory testing programs are being executed by the EU COST action SARCOS, each focusing on test methods for a specific self-healing technique. This paper reports on the comparison of tests for mortar and concrete specimens with polyurethane encapsulated in glass macrocapsules. First, the pre-cracking method was analysed: mortar specimens were cracked in a three-point bending test followed by an active crack width control technique to restrain the crack width up to a predefined value, while the concrete specimens were cracked in a three-point bending setup with a displacement-controlled loading system. Microscopic measurements showed that with the application of the active control technique almost all crack widths were within a narrow predefined range. Conversely, for the concrete specimens the variation on the crack width was higher. After pre-cracking, the self-healing effect was characterized via durability tests: the mortar specimens were tested in a water permeability test and the spread of the healing agent on the crack surfaces was determined, while the concrete specimens were subjected to two capillary water absorption tests, executed with a different type of waterproofing applied on the zone around the crack. The quality of the waterproofing was found to be important, as different results were obtained in each absorption test. For the permeability test, 4 out of 6 labs obtained a comparable flow rate for the reference specimens, yet all 6 labs obtained comparable sealing efficiencies, highlighting the potential for further standardization.

Analyzing the nonlinear part of a signal generated by the response of a sample to an elastic excitation is a powerful tool to gain information on the material microstructure, including the presence of damage. Analysis using band-pass filtering or equivalent methods is often difficult due to the low amplitude of the harmonics contained in the signal. This is the case for the detection of early damage in granular samples with damage induced by a quasistatic loading, as analyzed in this paper. An experimental study, based on the scaling subtraction method, is presented here, showing the possibility of monitoring the variation in the sample nonlinearity during the evolution of damage and allowing linking it to different physical processes. The efficiency of the method in eliminating nonlinear contributions due to the experimental setup is proved through a numerical analysis.