Effect of capillary rise on mechanical behaviour of unstabilized rammed earth
Résumé
Moisture ingress through capillarity has a great effect on the mechanical properties of unstabilized rammed earth (URE). Limited experimental studies exist to quantify this effect. In this paper, an experimental setup for the capillary test was designed. Rammed earth samples of 15cm x 15cm x 45cm equipped with humidity capacitive sensors were placed on a saturated layer of sand which imposes controlled matric suction at the base of the sample. The kinetics of the capillary rise was determined by continuous measurement of the mass of the sample, height of moisture, and relative humidity. Subsequently, unconfined compressive strength (UCS) tests were performed before and after capillary rise. Samples tested after capillary rise show a decrease in mechanical resistance of 95% (a usual compression strength of 1.4 MPa decreases until 0,07 MPa). Other samples, dried after capillarity, show under uniaxial compression tests a restoration in compressive strength by 80% of the original dried samples. In consequence, a loss of strength capacity is observed under the capillary rise cycle. This contributes to explain many pathologies encountered on rammed earth structures.
Domaines
Matériaux| Origine | Fichiers éditeurs autorisés sur une archive ouverte |
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