CONTROLLED PERMEABILITY FORMWORK (CPF) CONCRETE

This paper examines the material influences on the performance of Controlled Permeability Formwork (CPF) for use in concrete both from the point of view of understanding the changes occurring in concrete through the use of the system and its implications for practice. The material effects were investigated, considering a total of 6 vertical wall elements of dimensions 1500 x 300 x 150mm with 3 of each cast with PC and PC/PFA30 concrete (design strength 25, 37 and 45N/mm2) against both impermeable (IMF) and permeable (CPF) formwork. The tests methodologies employed quantified the effects of CPF on the surface characteristics and fabric of concretes through measurements of quantity of drain water expelled, cement content and surface hardness. Tests to assess the potential for and aspects of durability included permeation and abrasion. There was a reduction in volume of water expulsion through the CPF liner cast against PC/PFA concrete (and this increased with design strength) seeming to reflect lower initial water content and specific surface of solids with this material. The effects of CPF increased the binder content at the concrete surface with more pronounced effects obtained at lower design strength. These effects were generally slightly less apparent with PC/PFA concrete. CPF increased the surface hardness and the beneficial effects were greatest at low design strength. The ISA-10 and abrasion resistance tests indicate that low design strength concretes cast against CPF exhibited the greatest improvements.

Language

  • English

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Filing Info

  • Accession Number: 00964431
  • Record Type: Publication
  • ISBN: 087659229X
  • Files: TRIS
  • Created Date: Oct 24 2003 12:00AM