Analysis of Slump Test for Sand-Foam Mixtures

作者：Azimi Amir H^*

来源：Journal of Materials in Civil Engineering, 2017, 29(9): 04017109.

DOI：10.1061/(ASCE)MT.1943-5533.0001971

• Foam
• Rheology
• Sand-foam mixture
• Slump test
• Viscoplastic fluid
• Yield stress fluid

Sand-foam mixtures have many potential applications in the field of mining and construction. This paper conducts laboratory experiments to investigate rheological characteristics of sand-foam mixtures using free slump flow tests with a cylindrical geometry. It is expected that slump test can provide accurate results to identify the effects of sand concentration, foam: water ratio, and particle size on the rheology of sand-foam mixtures. Three distinct stages are observed in slump of sand foam mixtures. The effect foam: water ratio is more pronounced in variations of slump heights and diameters with time. Yield stress of sand foam mixtures are estimated using the slump model for cylindrical geometries. Estimated yield stress is overall in good agreement with the rheological measurements. Effect of particle size on yield stress of sand foam mixtures is found to be negligible except for dense mixtures (c(o) > 0.6) with higher foam: water ratio (G(f) = 0.3). The averaged bed shear stresses of mixtures are calculated using a simplified one-dimensional momentum equation. A comparison between the averaged bed shear stress and the yield stress of mixtures indicates two distinct behaviours of fluidlike and solidlike during the slump flow spread. Energy dissipation is estimated during the tests. The energy dissipation rates of light sand-foam mixtures are higher than those of dense mixtures. The total energy dissipation of sand-foam mixtures is approximately 95%, which is 10% higher than the energy dissipation of granular flow.

• 出版日期2017-9