Effects of boiling and fiber length on the resistivity of coconut-fiber-reinforced mortar

This study measured the resistivity, tensile strength, water absorption, and compressive strength of CF-reinforced mortars (CFRMs) prepared from boiled or raw CFs of various lengths (1.5, 2.5, or 4 cm) at 2.9 wt% in accordance with ACI 544. Scanning electron microscopy investigations of the microstructure revealed that boiling CFs increased their number of open pores (lumen), leading to higher water absorption and lower tensile strength. Resistivity tests revealed that the raw-fiber CFRMs had higher resistivity than the boiled-fiber CFRMs and increased resistivity with decreased fiber length. Finally, strong linear relationships of resistivity with compressive strength and water absorption were identified.