TY - JOUR A1 - Farhat, Abbas A1 - Philippe, Pierre A1 - Luu, Li-Hua A1 - Doghmane, Alexis A1 - Cuéllar, Pablo T1 - Hydraulic failure of granular materials with artificial cementation N2 - This paper presents an experimental study on the hydraulic failure of a submerged layer of cemented soil stressed by a localized upward water flow. Different mixtures of glass beads bonded with solid paraffin bridges were used as artificial material for the cemented granular soil. Variations in the cementation strength of the material were carefully introduced with different particle sizes and binder contents. The hydraulic fracture tests were then carried out with an upward flow injected at a controlled rate through a small section at the bottom of the samples. From a phenomenological perspective, the results reveal the existence of at least three modes of failure for a cemented soil layer: (1) overall block uplift, (2) block rupture by median crack at the inflow zone, and (3) progressive excavation of a fluidized path along the walls. The critical flow rate and pressure drop conditions at failure have been carefully quantified for the different mixtures and layer thicknesses, leading to a fair estimation of the hydraulic resistance of the samples, which here is found to be virtually independent of the grain size. However, the test results also showed inconsistent failure modes precluding so far the derivation of a simple phase diagram. Nevertheless, it was possible to rationalize all the measured data by employing appropriate modifications of the classical dimensionless numbers that describe the fluidization of purely frictional materials, whereby the cementation strength of the soil is quantified at the microscale through the yield tensile force of the intergranular bonds. Irrespective of its subsequent development, during which boundary conditions obviously play a major role, the initiation of the instability appears to take place very locally at the inlet when the drag force induced by the flow overcomes the cementation strength of the paraffin bonds. The results of this study thus appear to endorse the extension of the dimensional relationships of particulate systems in interaction with fluid flows to the case of cemented granular materials, in a similar vein as in recent previous studies. KW - Fluidized beds KW - Granular materials KW - Fluid Dynamics KW - Cemented soil PY - 2024 DO - https://doi.org/10.1103/PhysRevFluids.9.064305 SN - 2469-990X VL - 9 IS - 6 SP - 1 EP - 13 PB - American Physical Society AN - OPUS4-60803 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lopez Meza, Sarynna A1 - Kalbe, Ute A1 - Berger, Wolfgang A1 - Simon, Franz-Georg T1 - Effect of contact time on the release of contaminants from granular waste materials during column leaching experiments N2 - When reusing or disposing of contaminated granular waste materials there is a need to evaluate how the contaminants will interact on the pathway soil-groundwater and the effect this interaction will have on the surrounding environment. While column testing can provide a closer approximation to field percolation conditions than batch testing, there is still a need to develop column testing procedures that consider the requirements of practical testing time frames. This study evaluates the effect of different column contact times (2.5, 5, and 16 h) on the release of inorganic constituents from bottom ash and demolition waste, two commonly reused granular materials. Leaching data for representative constituents of concern, such as copper, chromium, sulfate and chloride, as well as pH and electrical conductivity was compared for all different contact times studied. Results for the materials investigated in this study showed that variations in contact time have no significant effect on the release of the selected constituents and leaching parameters at low liquid to solid ratios. However, after a liquid to solid ratio of 1 L/kg, the effect is more noticeable, and higher contact times show lower pH values as well as a reduction in the release of constituents of concern from bottom ash. In the case of demolition waste, the variation of contact time did not have a strong effect on the leaching behavior. KW - Leaching procedures KW - Standardisation KW - Column tests KW - Contact time KW - Granular materials KW - Waste PY - 2010 DO - https://doi.org/10.1016/j.wasman.2009.11.022 SN - 0956-053X VL - 30 IS - 4 SP - 565 EP - 571 PB - Pergamon Press CY - New York, NY AN - OPUS4-20934 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lopez Meza, Sarynna A1 - Garrabrants, A.C. A1 - van der Sloot, H. A1 - Kosson, D.S. T1 - Comparison of the release of constituents from granular materials under batch and column testing N2 - Column leaching testing can be considered a better basis for assessing field impact data than any other available batch test method and thus provides a fundamental basis from which to estimate constituent release under a variety of field conditions. However, column testing is time-intensive compared to the more simplified batch testing, and may not always be a viable option when making decisions for material reuse. Batch tests are used most frequently as a simple tool for compliance or quality control reasons. Therefore, it is important to compare the release that occurs under batch and column testing, and establish conservative interpretation protocols for extrapolation from batch data when column data are not available. Five different materials (concrete, construction debris, aluminum recycling residue, coal fly ash and bottom ash) were evaluated via batch and column testing, including different column flow regimes (continuously saturated and intermittent unsaturated flow). Constituent release data from batch and column tests were compared. Results showed no significant difference between the column flow regimes when constituent release data from batch and column tests were compared. In most cases batch and column testing agreed when presented in the form of cumulative release. For arsenic in carbonated materials, however, batch testing underestimates the column constituent release for most LS ratios and also on a cumulative basis. For cases when As is a constituent of concern, column testing may be required. KW - Leaching KW - Batch tests KW - Column tests KW - Granular materials PY - 2008 DO - https://doi.org/10.1016/j.wasman.2007.11.009 SN - 0956-053X VL - 28 IS - 10 SP - 1853 EP - 1867 PB - Pergamon Press CY - New York, NY AN - OPUS4-17797 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lopez Meza, Sarynna A1 - Kalbe, Ute A1 - Berger, Wolfgang A1 - Simon, Franz-Georg T1 - Harmonization and validation of leaching standards - new developments in Germany N2 - This article presents a snapshot of key issues regarding characterization of granular waste materials with respect to their reuse as alternative construction materials, and the factors that need to be considered in their reutilization in order to comply with soil and groundwater protection regulations. KW - Column tests KW - Granular materials KW - Leaching protocols KW - Standardisation KW - Waste PY - 2008 DO - https://doi.org/10.2462/09670513.890 SN - 0967-0513 VL - 16 IS - 1 SP - 45 EP - 49 PB - EPP Publ. CY - Richmond AN - OPUS4-17376 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -