This study evaluates the influence of moisture conditions on the mechanical properties of a mixture comprising 35% dune sand and 65% tuff, treated with 2.66% lime and 1.33% cement. This composition has previously demonstrated optimal structural performance for pavement applications in Saharan regions. To replicate realistic field conditions typical of Saharan climates, a range of water contents was tested under curing scenarios that reflect actual environmental fluctuations. The experimental program included California Bearing Ratio (CBR) tests, unconfined compressive strength (UCS) tests, splitting tensile tests, and unsaturated triaxial tests performed at water contents of 0%, 2.8%, 5.5%, 8%, 10.5%, 12.8%, and 15%. The results reveal that, (1) the CBR value decreased linearly from 141 to 101% as water content increased. (2) The compressive shear strength (qc) declined hyperbolically with water content but followed a parabolic increase with suction, regardless of confining pressure. (3) Treatment significantly improved qc, rising from 1.71 MPa to 3.08 MPa at 0% water content, and from 0.7 MPa to 5.6 MPa at 15% water content. (4) The apparent cohesion dropped linearly from 605 kPa to 352 kPa across the tested moisture range, while the apparent friction angle remained stable between 49 degrees and 52 degrees. (5) Tensile strength (qt) exhibited an exponential decline with water content, yet at the highest water content, treatment enhanced qt from 23 kPa to 275 kPa. (6) Linear relationships were also obtained between mechanical parameters, notably CBR = 0.045 UCS and qt= 0.012 UCS. (7) The proposed correlations demonstrated strong predictive performance, making them valuable tools for practitioners assessing the behavior of treated Saharan soils. Overall, the findings underscore the potential for using locally available materials, specifically dune sand and tuff, in the construction of efficient, moisture-resilient, and cost-effective pavement layers that support sustainable development goals in arid regions.