Assessing the bond strength of Glass Fiber Reinforced Polymer (GFRP) bars in Portland Cement Concrete fabricated with seawater through pullout tests

Abstract

Portland Cement Concrete (PCC) is the most used construction material worldwide and its use is expected to increase in the future. PCC intensively uses two main natural resources, namely aggregates and fresh water. The concrete industry consumes about 2 billion tons of potable water annually. Due to climate change, rapid population growth, and industrial activity, there is a scarcity of fresh water; by 2025 more than half of the world’s population will be living in water-stressed areas. In contrast, there is abundant seawater in the world, which represents about 97.5% of the total Earth’s water. However, the incorporation of seawater in PCC is a complex problem because the sulfate ions can affect the microstructure durability and the chloride ions can accelerate reinforcing steel corrosion, which can compromise the structural integrity. Glass Fiber Reinforced Polymer (GFRP) bars may be used as an alternative reinforcing material to avoid corrosion. This paper assesses the bond strength of two types of GFRP bars with either a sand-coating or spiral grooves using a standard pullout test. Control samples were prepared using concrete made with potable water and compared with companion specimens made with seawater. Parallel experimental programs were carried out in Chile and Canada, with a total of 70 test specimens. The results suggest that there is no statistically significant difference in the short-term (28 day) bond strength of GFRP bars in seawater concrete compared to normal concrete.