Linear and nonlinear elastic waves for early detection and characterization of structural changes in cement-based materials
About 8% of the worldwide anthropogenic CO2 emissions is contributed by concrete, most of it due to cement production. This issue has stimulated the development of new low-carbon footprint binders. In parallel, there is urgent need for speeding up and upscaling the characterization of the long-term durability properties of these novel materials.
This PhD project (of Ye Zhu) aims at advancing the application of non-destructive evaluation and characterization methods based on sound/ultrasound waves, with focus on three main topics.
(1) Development and optimization of methods for measuring linear and nonlinear elastic moduli of cement-based materials, to be used as macroscopic proxy variables of the "damage state".
(2) Optimization of other methods, namely wave dispersion measurements and coda wave interferometry, for cement-based materials characterization. The former will be used for characterizing carbonation in blends of Portland cements and SCMs. The latter will be employed to characterize the structural evolution during setting and hardening of materials cast with unconventional binders.
(3) Investigation of the correlations between cracking features and nonlinear elastic moduli in diverse degradation processes related to durability properties.
The developments and results of this PhD project will advance the understanding and the systematic characterization of durability properties, thus accelerating the development and adoption of new materials with reduced CO2 footprint.
Fabruary 2019 - January 2023
LafargeHolcim Innovation Center