Flowable fill mixes

Natural sand is a major component of most flowable fill mixes. Ferrous spent foundry sand can be used as substitute for natural sand (fine aggregate) in flowable fill.48 49 Spent sands from nonferrous foundries and foundry baghouse dust can contain high concentrations of heavy metals that may preclude their use in flowable fill applications. Some of the engineering properties of spent foundry sand that are of particular interest when foundry sand is used in flowable fill applications include particle shape, gradation, strength characteristics, soundness, deleterious substances, and corrosivity. 

Bottom ash has been used as an aggregate material in flowable fill mixes Ponded ash also has the potential for being reclaimed and used in flowable fill Since most flowable fill mixes involve the development of comparatively low compressive strength, no advance processing of bottom ash or ponded ash is needed... 

Neither bottom ash nor ponded ash needs to be at any particular moisture content to be used in flowable fill mixes, because the amount of water in the mix can be adjusted in order to provide the desired flow ability... 

Construction procedures for flowable fill materials are no different than those for conventional earth backfill materials. The same methods and equipment used to mix, transport, and place flowable fill made with conventional aggregates may be used for flowable fill incorporating spent foundry... 

Mixing Proportions of Flowable Fill with Spend Foundry Sand (kg/m3)... 

Other potential applications include its use as an aggregate in flowable fill, hot mix asphalt concrete, and surface treatments To be used as an aggregate ... 

Applications that could potentially make use of SSA in highway construction include the use of ash as part of a flowable fill for backfilling trenches, or as a substitute aggregate material or mineral filler additive in hot mix asphalt... 

Lecithin will function as a release agent, providing cleaner and faster pet food or biscuit parting from a stamp or mold. A reduction in the amount of pressure required to create an impression with a stamp is seen when lecithin is used in the mix. The ease of formation of intricate, stamped, surface appearance details, especially with low-fat products, is also improved with lecithins. When dough is being cut, lecithin improves release from the die, especially with rotary cutters. With superior release, foods and biscuits are formed with a better impression, and lower numbers of cripples (i.e., improperly formed product). Some pet biscuits are formed from a batter injected into a mold prior to cooking. Lecithin can improve flowability of the batter so that it fills all the mold corners and cavities. After cooking, lecithin improves release from the mold. 

In the food, detergent and cement industries, hoppers used to store powders prior to filling containers such as sacks, cartons or tins are often fluidized locally to improve flowability and reduce flow problems. Fluid beds may also be employed to blend the ingredients before filling. Here it is clearly important to ensure that components are well mixed so that each container receives the correct average mixture. 

In the case of fibre reinforced composites a special measure of workability was proposed by ACI 544.2R-89 called inverted slump cone. A standard Abrams cone is suspended upside down and filled with tested material without any compaction. The internal vibrator is activated and the bottom cover of the cone is removed, then the time of flow out of the material is recorded, which is usually between 10 and 30 seconds. This method is still in use, but is subject to some criticisms. Other methods of the flowability of the fresh mix with dispersed fibres are proposed by Laboratoire des Fonts et Chaussees in France (cf. Section 12.5). 

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