Cheikh Sleiman, H;
Tengattini, A;
Briffaut, M;
Huet, B;
Dal Pont, S;
(2022)
Drying of mortar at ambient temperature studied using high resolution neutron tomography and numerical modeling.
Cement and Concrete Composites
, 131
, Article 104586. 10.1016/j.cemconcomp.2022.104586.
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Abstract
The drying of cement-based materials, naturally occurring in most civil engineering contexts, affects their thermal, hydraulic and mechanical properties and is a leading contributor to the loss of their durability potential. The techniques conventionally employed to study this moisture transfer, such as gravimetry weight loss and point-wise sensor-based measurements, are often destructive and cannot characterize the local driving phenomena in 4D (3D+time), essential given the highly heterogeneous nature of the involved processes. Conversely, full-field techniques, and notably neutron tomography, are non-invasive and ideal for measuring the moisture transport process due to the high attenuation of neutron by hydrogen. In this study, the moisture distribution of a set of cylindrical mortar samples was characterized at different hydric states, as imposed through drying in a thermo-hydrically controlled environment (T=20 °C, RH=35%). The lateral surfaces of the samples were sealed to impose a unidirectional moisture flow. The main phases of the mortar (aggregates, cement paste and voids), visible at the 30μm resolution adopted, were separated, and saturation profiles were deduced and validated against the mortar mixture ratios and weight loss measurements. Besides the intrinsic interest of the spatio-temporal evolution of the local extracted saturation, these hydric gradients are essential to calibrate numerical models, as the commonly used Finite Element model presented here. A minimization algorithm was developed for this purpose to automate, optimize and ensure a more objective numerical–experimental calibration procedure. This has allowed the identification of key hydric parameters such as the convective exchange coefficient and the intrinsic permeability.
| Type: | Article |
|---|---|
| Title: | Drying of mortar at ambient temperature studied using high resolution neutron tomography and numerical modeling |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1016/j.cemconcomp.2022.104586 |
| Publisher version: | https://doi.org/10.1016/j.cemconcomp.2022.104586 |
| Language: | English |
| Additional information: | This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | Drying of cement-based materials, Neutron tomography, Numerical modeling, Hydric profiles |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Mechanical Engineering |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10215028 |
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