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Description
Timber has been widely adopted since humans started constructing buildings and sees increasing interest as effective carbon sink compared to conventional building materials like steel and concrete. An organic material, wood is prone to moisture-induced biodegradation over sustained wet periods while swelling/shrinkage deformation can occur in a matter of minutes. Water loads on buildings are majorly affected by climate change, with varying wind-driven rain loads and increased risks of flooding, be it fluvial or pluvial. Understanding moisture transport in wood remains as crucial as ever for optimal application of timber and advanced imaging is offering new paths to document wood-water interactions.
Wood has a particular structure as a sparse network of long tube-like pores (lumen cells) connected by small throats (pits). Spontaneous imbibition in wood eludes common continuum models, shows irregular flow dynamics and, to this day, is only poorly understood at cellular scale.
We study spontaneous water imbibition in a sample of spruce wood by fast X-ray tomographic microscopy at the TOMCAT beamline of the SLS, Paul Scherrer Institut, and at the ID19 microtomography beamline at ESRF. We recorded 120 tomographic scans at 2Hz for the first 60s capturing the fast initial water uptake with 2.75 um voxel size and 70 scans every 34s with 1um voxel size to observe the subsequent slow network filling and hygroscopic absorption resulting in lumen deformation.
We combine the analysis of capillary filling with digital volume correlation to trace the coupled nature of heterogeneous pore filling and hygroscopic swelling. We find an initial fast phase of capillary filling of open pores, followed by staggering network filling with delayed throat transitions and a diffusion dominated hygroscopic moisture uptake in the solid nanoporous phase.
| Country | France |
|---|---|
| Green Housing & Porous Media Focused Abstracts | This abstract is related to Green Housing |
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