In a June 1994 article, Concrete Journal readers were invited to send in information about their use of flowable fill. Here are two of the responses received.
David P. Twomey, executive director of the Northern New England Concrete Promotion Association (NNECPA), Scarborough, Maine, forwarded a copy of NNECPA's specifications for flowable fill. NNECPA specifies flowable fill for trenches, support for pipe structures, culverts, utility cuts, and other works where cavities exist and where firm support is needed for pavements and structural elements. NNECPA recommends flowable fill be proportioned to produce a 28-day compressive strength of approximately 75 to 100 psi to establish removeablility.
Victor Smith, quality control manager for Ewell Industries Inc., Tampa, Fla., notes there are many applications for flowable fill on the west coast of Florida. Ewell Industries has developed flowable mixes to be an economical replacement for compacted fill. Their mix specifications call for a set time of around three hours, and a 28-day compressive strength not to exceed 500 psi. Ewell uses a flowable fill performance additive in all of their flowable fill mix designs. The additive helps control strength development in applications calling for future excavation and produces 20% to 30% entrained air in the flowable fill.