CIA CPN33-2002

Current Practice Note 33 is an update of the previous CPN 10 " Compacting concrete on building sites." CPN 33 explains the reasons for compacting concrete and then describes the methods of compaction using immersion and surface vibrators. The updated version of the American Concrete Institute's table, "Characteristics and applications of internal vibrators" is then presented. A procedure for checking the effectiveness of immersion vibrators is included. (also by courtesy of ACI). Table 2 is a "Summary of causes of surface defects relating to concrete, placement and compaction (ACI Committee 309). The vibration techniques for walls, columns and floors are then described. A quick checklist is then given for those who supervise compaction of concrete on the job (Appendix A). There is also a checklist for those who operate immersion/poker vibrators (Appendix B). Appendix C discusses the response of freshly placed concrete to vibration, revibration and over-vibration and under-vibration. The text is supported by a list of informative references and a short bibliography.