COMPARATIVE STUDY ON DURABILITY OF 150MPa ULTRA-HIGH PERFORMANCE FIBER REINFORCED CONCRETE (UHPFRC) MEMBER WITH CRACKS UNDER CHLORIDE ENVIRONMENT

摘要

Ultra-High Performance Fiber Reinforced Concrete (UHPFRC) has characteristics of high durability and low chloride ion diffusion coefficient which is suitable for bridge construction material. UHPFRC is made of mixture of cement, sand, lime, silica fume and Polyvinyl Alcohol (PVA) Fiber to achieve 150 MPa compressive strength. However, bending cracks will affect the performance of concrete. The aim of this research is to study the trend and the effect of corrosion after implementation of cracks on surface. UHPFRC specimen is utilized with limited concrete cover thickness of 40mm and 20mm. Bending crack width range from 0mm to 0.46mm was created on surface of specimen. Half-cell potential, polarization resistance and passivity grade was used to determine the trend and effect of corrosion. Experimental results show UHPFRC specimen with cover thickness 20mm is acceptable with a crack width less than 0.12mm. Repair works are necessary for crack width more than 0.12mm. Finally, silane coating was applied to ensure long time service life.