Durability of concrete confined with GFRP tube

Abstract EN

One promising innovative structural system is concrete-filled fibre reinforced polymer (FRP) tubes, which provide many unique advantages.

The FRP tube acts as a stay-inplace structural formwork to contain the fresh concrete, which may save the costs of formwork and labour used by cast-in-place or pre-cast industries.

At the same time, the FRP tube acts as a non-corrosive reinforcement for the concrete for flexure and shear.

More importantly, the FRP tube provides confinement to the concrete in compression, which significantly improves the strength and ductility.

The contained concrete is protected from severe environmental effects and deterioration resulting from moisture intrusion.

This thesis presents results of an experimental study on the durability performance of concrete cylinders confined with glass-FRP (GFRP) tubes.

The study includes 40 plain and FRP-confined concrete specimens of which 16 specimens were standard 150 x 300 mm concrete cylinders and 24 specimens consisted of 167 x 334 mm concrete-filled GFRP tubes.

The concrete filled GFRP tubes are mainly considered for new structures and not for rehabilitation purposes.

One half of the specimens were made of normal weight concrete while the other half was made of lightweight concrete.

For each type of concrete, two groups of identical specimens were kept inside the environmental chamber, with and without sustained axial compression load and subjected to 150 cycles of freeze-thaw as in actual structures, which may have a synergetic effect.

Also, two similar groups of specimens were kept at room temperature.

All the specimens were tested to failure under axial compression and the effect of different variables on the ultimate strength, stress – strain behaviour and mode of failure were discussed.