Temperature Effect on the Hygroscopic Behavior of a Soil–Powdered Apricot Nut Shells Bio-Composite Building Material

¹ Cadi Ayyad University, Faculty of Sciences Semlalia, Department of Physics, Fluid Mechanics and Energetic Laboratory, Unit Affiliated to CNRST (URL-CNRTST No 16), B.P. 2390, Marrakesh, Morocco
² Engineering & Applied Technologies Laboratory (LITA), Higher School of Technology, Sultan Moulay Slimane University, Beni Mellal, Morocco

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Published online: 22 May 2026

Abstract

A bio-composite building material composed of locally sourced soil reinforced with powdered apricot nut shells (PANS) was investigated with respect to its hygroscopic behavior under different temperature conditions. Moisture adsorption and desorption isotherms were determined at 30 °C, 40 °C, and 50 °C using the static gravimetric method. The study focused on a reference soil (0 % PANS) and a soil–PANS composite containing 2 % PANS by mass. The results show that increasing temperature leads to a systematic reduction in equilibrium moisture content, while higher relative humidity enhances moisture uptake. The obtained sorption isotherms exhibit a Type IV profile, characteristic of mesoporous materials. The Peleg model provided an excellent fit to the experimental data for both adsorption and desorption branches, with correlation coefficients exceeding 0.97. The incorporation of 2 % PANS modifies the moisture-buffering behavior of the soil matrix by enhancing pore connectivity and moisture retention capacity. These findings contribute to a better understanding of the hygric performance of soil–PANS bio-composites and support their potential application in sustainable building envelopes exposed to variable climatic conditions.