Gas relative permeability of high-performance concrete: effect of water saturation under phase desorption and sorption

Title: Gas relative permeability of high-performance concrete: effect of water saturation under phase desorption and sorption
Author(s): Wei Chen, F. Skoczylas, T. Dubois
Paper category : conference
Book title: International RILEM Conference on Advances in Construction Materials Through Science and Engineering
Editor(s): Christopher Leung and K.T. WAN
ISBN: 978-2-35158-116-2
e-ISBN: 978-2-35158-117-9
Publisher: RILEM Publications SARL
Publication year: 2011
Pages: 777 - 784
Total Pages: 8
Nb references: 14
Language: English

Abstract: This experimental work investigates the hydraulic behavior of two different high-performance concretes (called CEMI and CEMV), in order to improve the understanding of the effect of water saturation on relative permeability, during sorption and desorption phases. Each material is put more than 500 days over water or saline solution in order to change its saturation. Nine samples, for each concrete, are tested from saturated to dry state after stabilization in hermetic chambers at different fixed relative humidity: 98, 92, 85, 75, 70, 59, 43, and 11%. An additional sample is tested after drying at 65°C, which is considered as the reference state for gas permeability measurements. The Pulse-Test method, with a static gas pressure of 2MPa and an overpressure of pulse of 0,5MPa, is used to measure effective gas permeability.
Firstly, gas permeability is measured during desorption phase, for each RH, after mass stabilization. Secondly, all samples are dried in an oven at 65°C, and then intrinsic gas permeability is measured. Finally, each sample is put for a second time in the same hermetic chamber in order to be re-saturated at the same RH: it is the sorption phase. For this phase, three tests are done for each sample at three different times. These tests show a hysteretic phenomenon during the concrete imbibition phase. The amplitude of hysteresis decreases with time. Besides, both concrete have very close intrinsic gas permeability, but significantly different effective and relative gas permeability. All the results mean that gas permeability mainly depends on saturation state, whatever the path of saturation, except for the CEM I at the end of the re-saturation process.

Online publication: 2011-10-31
Publication type : full_text
Public price (Euros): 0.00