Effect of Controlled Permeable Formwork in Concrete Using Woven and Non-Woven Fabric as CPF Liner

Thoyajakshudu Chalamarla, Dr. K. Thulasirajan

Abstract: Surface quality of the concrete is important for the durability of reinforced concrete structure, because the cover stands at the forefront defending both mechanical damages and chemical deterioration. Controlled permeable formwork (CPF) liner was developed primarily to improve the surface quality of concrete and thereby its durability. CPF liner drains mix water and entrapped air from the near surface of concrete while retaining cement and other fine particles. This helps to reduce water-cement ratio, increase cement content and decrease surface pores in the surface zone of concrete. This paper reports an experimental study carried out to study the effect of CPF liner on the strength and certain mechanical properties of concrete with three different grades of concrete. M20 & M4O was chosen for the present study. The specimens were prepared against CPF liner and impermeable steel formwork (IMF) and tested at 28 days. Various tests such as compressive, split tensile strength, rebound hammer and ultra-sonic pulse velocity tests were conducted on the normal and CPF lined concrete. The results indicate that CPF concrete performed better than IMF concrete in all aspects. From the test results, the use of CPF liner in different grade of concrete (M20&M40) improved the mechanical properties due to the formation of strong and dense Cover-Crete.

Keywords: Controlled permeable formwork, Concrete, Properties