The use of biomass ashes as cement replacement have become a notable and trending aspect due to the huge increase in the pollution levels caused by the manufacturing process of cement. Phragmites Australis Ashes (PAA) can be an eco-friendly alternative to cement since it can be burnt in a closed container decreasing the CO2 emissions into atmosphere. Also, PAA is considered an economical material since it is available locally and grows massively on the banks of the rivers in Lebanon. The performance of mortar mixes produced by a partial replacement of cement were evaluated in this paper revealing a big potential for PAA to be used as cement replacement. Cement in mortar specimens was replaced by 0, 10, 20 and 30% by weight PAA. Mix proportions and water to binder ratio were set constant for all casted mixes. Durability properties, including total water absorption and capillary water absorption, containing different PAA percentages were evaluated at 1, 7, 28 and 90 days of curing ages in comparison to the control specimen. The test results show an increase in the total water absorption percentages as PAA percentage is enhanced in mixes. The same trend was also obtained for capillary water absorption test.