Design and validation of a minimalist, open-source system for measuring elastic modulus evolution in cementitious materials

The elastic modulus evolution of cementitious materials since early ages can be experimentally measured with the EMM-ARM (Elastic Modulus Measurement through Ambient Response Method) test. This methodology has been extensively validated, but its original implementation relied on costly proprietary platforms. A minimalist, open-source test system may provide a benchmark that sets minimum requirements and performance to enable the development of tailor-made systems. This work aimed to develop, characterise, and validate such system, composed of data-acquisition hardware and post-processing software. Characterisation results showed the system had a spectral noise floor of 2.1 x 10-8 g2/Hz, an RMS noise of 0.003 g, a sampling frequency variability of +/- 0.006%, and an average power consumption of 41.53 mAh. Compared to an original EMM-ARM system, validation results indicated the proposed system had an absolute error lower than 0.3% from 1 day of testing onwards, with a similar coefficient of variation of 1.2%.