Prestress loss in externally FRP reinforced self prestressing concrete beams

• Lime-system expansive-concrete (EC) beam achieves a considerable effective prestress level.
• Lime-system EC shows the lowest prestress loss and highest residual compressive stress.
• Shrinkage and creep of expansive concrete were simulated by a modified model.
• Analytical calculation shows good agreement with experimental observation.

Hybrid fiber-reinforced polymer (FRP) reinforced expansive concrete (EC) structural system shows a good potential for delaying concrete cracking and eliminating steel corrosion. In this study, long-term expansion-shrinkage strain development and prestress loss of the proposed system are investigated. Test results were evaluated based on maximum expansion strain, concrete strength and strain loss. An analytical model consisting of shrinkage, creep of expansive concrete as well as relaxation of steel was developed from GL2000. The comparison of the strain loss between tested results and calculation was presented. Results show that lime-system EC presents a higher prestress strain and lower prestress loss than ettringite-system EC in the long term. Calculated results from the developed model and experimental data show a good agreement.