Strength and Surface Quality Properties of SCC Made Using Controlled Permeable Formwork Liner

Abstract

The corrosion of reinforced concrete structures as a major problem throughout the world, it leads to significant costs of repair and retrofitting. All the aggressive agents are penetrating into the concrete through the surface of concrete to initiate the rebar corrosion. Controlled Permeability Formwork (CPF) is the active method to improve the quality of surface zone of concrete. This technique is used to drain the surplus water and entrapped air from the near surface of fresh concrete whilst retaining the cement and other fine particles. This ensures reducing the water-cement (w-c) ratio, enrich of cement content and decrease of surface porosity in the cover zone of the concrete. CPF action creates smooth surface with free from pin and blow. This paper reports an experimental study carried out to investigate the influence of CPF liner on the mechanical and surface quality properties of self-compacting concrete (SCC). The specimens were prepared against CPF liner and impermeable steel formwork (IMF) and tested at 7, 14, 28 and 60 days. The tests that were carried out include compressive, split tensile and flexural strengths, rebound number, ultrasonic pulse velocity and abrasion resistance. The results reveal that the CPF concrete specimens had significant improvement against tensile strength and rebound number when compared to IMF concrete specimens. The top 20 mm concrete quality has been enhanced by use of CPF liner on SCC.