Hygroscopic behavior of water absorbed by capillarity and stabilization of a bio-composite building material: Clay reinforced with Chamarrops humilis fibers

The paper aims to study the hygroscopic behavior of water absorbed by capillarity of clay reinforced with Chamarrops humilis fibers as an ecologic building material strongly used in building construction in Morocco. This leads to provide a better understanding and controlling hydrothermal behavior of a building material, which integrates sorption phenomenon and its intrinsic characteristics. The static gravimetric method was used to determine sorption isotherms. Six salts were chosen so as to have a range of air relative humidity of 5.72% to 89.8%. The results showed that the water content absorbed by capillarity increases with the increasing of the air relative humidity at a given temperature, and the equilibrium water content absorbed by capillarity decreases with the increasing temperature. The sorption isotherms are of type IV, showing that the water absorption is enhanced at low humidities and a strong dominance of macropores. The differential enthalpy and entropy of sorption show that there is a strong dependence on the air relative humidity. Stabilization of clay by adding fibers indicated a strong influence on the rate of equilibrium moisture content loss, this leads to prevent cracking of earthen structures during the drying period by distributing the tensions due to shrinkage.