Abstract
In South Africa, concrete in large diameter bored piles is generally placed by discharging a high flow concrete mix directly from the truck mixer and allowing the concrete to fall freely to the base of the pile hole. While certain site practices have been used by piling contractors for years, many engineers are not convinced of their acceptability. This paper discusses the results of an investigation which assessed the effect of site practices on the integrity of cast in-situ bored piles. Such practices include the method of concrete placement and the amount of water and/or loose spoil in the pile hole at the time of casting. The results of this investigation dispel the myth that the free fall placement of concrete in clean, dry pile holes has a detrimental effect on the degree of compaction and compressive strength of the concrete.