Degradation of Fiber Reinforced Mortar in a Marine Environment

Concrete is a brittle material with a relatively low tensile strength compared to its compressive strength. Reinforcement with randomly distributed short fibers could improve the ductility and tensile strength of concrete and permits the stabilization of the crack system. These products could be used in marine applications, but several chemical reactions must be controlled to generate durable materials. Sulfates and chlorides presented in seawater are especially dangerous ions for the concrete and the reinforcing steel.

The main objective of this research was to determine the effects of a marine environment on the properties of fiber reinforced mortars. Different types of natural and synthetic fibers such as sisal (S), fique (F), coconut (C), glass (G), polypropylene (PP) and steel (St) were used. The physical, mechanical and durability properties of the mortar made with each type of fiber were determined. The mortar matrix included additions such as silica fume (SF), and a superplasticizer (SP). Durability properties under marine environments were evaluated by measuring chloride ion penetration and water absorption.

The test results indicate an increase in the matrix porosity due to fiber application, but the blended cement matrix showed superior performance compared to the portland cement under marine service conditions. The utilization of mineral additions and additives in fiber reinforced mortars under severe environments was recommended.