Abstract:
The objective of research is to investigate the effects of Palm Oil Fuel Ash on compressive strength, Chloride Diffusion Coefficient (Dc ), and steel corrosion of concrete after being exposed to the marine environment for 5 years. Water-to-binder ratios (W/B) were carried at 0.40, 0.45 and 0.50. Palm oil fuel ash (the particles retained on a sieve #325 ≤ 1.5%) to partially replace portland cement type I at the percentages of 0, 15, 25, 35 and 50 by the weight of binder. The 200-mm concrete cube specimens were cast and steel bars with 12-mm diameter and 50 mm in length, were inserted with the covering depth of 10, 20 and 50 mm. Besides, the cylindrical specimens of 100-mm in diameter and 200-mm in height were cast for compressive strength test and then cured in fresh water for 28 days. Subsequently, the specimens were tested to determine the compressive strength, the total chloride contents, and the surface loss of steel corrosion after being exposed to tidal zone for 5 years. The results showed that chloride diffusion coefficient (Dc ) and steel corrosion were clearly decreased with replacing palm oil fuel ash ≤ 25% by weight of binder including the increased compressive strength. However, high volume of palm oil fuel ash replacement (up to 50% by weight of binder) did not well prevent the chloride resistance and steel corrosion. Moreover, high volume of water-to-binder ratio increased the chloride diffusion coefficient (Dc ) and this was shown clearer in normal concrete than palm oil fuel ash replacement concrete. Besides, the model for predicting chloride penetration showed that the predicted chloride concentration had margin of error within ± 30%.