Evaluation of Different Methods of Surface Treatment of Natural Açai Fiber Added in Cementitious Composites

Açai fiber has a characteristic that enhances its application as a reinforcement material in mortars. One of the major problems in the use of natural fibers in cementitious composites is the alkalinity of the porous of these materials, which can be solved by applying surface treatment to the fibers. The objective of this work was to evaluate four different forms of surface treatment of natural Açai fibers, washing them with water, with cyclohexane/ethanol, immersing them in a solution of NaOH or alkaline peroxide, adding them in 4% in relation to the mass of cement in mortars of cement, and lime for coating. Properties such as consistency, incorporated air content, linear shrinkage, mechanical resistance, and water absorption were evaluated, according to Brazilian standards. The results showed that the treatment with alkaline NaOH solution is the one that best managed to modify the surface of the fibers, improving the evaluated technological properties.