Strength and permeability of fly ash-modified concrete in coastal construction

Three vital factors, namely environmental protection, savings in energy, and technical benefits, make it advantageous to incorporate fly ash of controlled quality and composition in all concrete construction. The specific objective of this research was to compare the performance characteristics of fly ash-modified concrete with that of normal concrete in the coastal environment. To make this comparison, a series of tests using appropriate ASTM standards were conducted. First, the compressive strength development of five mixes was studied. Reinforced beam specimens were then subjected to varying periods of accelerated corrosion with sea water as electrolyte. These were tested under flexure and impact. An attempt was made to predict remaining life. Finally, permeability tests were carried out. Results indicate that fly ash increases compressive strength, improves both moment carrying capacity and impact resistance, and increases watertightness.