Glass fiber-reinforced polymer rods, both bare and embedded in concrete or lime mortar, were immersed in an alkaline solution at 20°C for up to 6 months and tested to find the influence of the protective covers on the degradation of the rods.

Diffusion and porosimetry studies were used to interpret the results. Reduction of the proportion of larger pores in the mortar cylinders altered the transport of contaminant to the reinforcing bars. Accelerated effects due to immersion in solution at 60°C caused marked degradation of the rods. SEM images revealed damage to the matrix and the interface fiber-resin, mostly noticeable on the resin matrix and in the peripheral region of the rods.

Severe loss of capacity of energy absorption was found in low-velocity impact tests after exposure to solution at 20°C for more than 5000 hours. Globally, results showed that the embedment delayed the initiation of damage but did not shield the rods against the maximum intensity of degradation by the alkaline contaminant.

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