the effect of the particle size distribution on non-newtonian turbulent ...

Chapter 3 Experimental Work Page 3.19
3.5.2 Solids Relative Density
The relative density <strong>of</strong> <strong>the</strong> solids (S,) is determined using test method 6B for fine grained
soils from BS 1377 (1975).
3.5.3 Slurry Temperature
A mercury <strong>the</strong>rmometer was used to measure <strong>the</strong> temperature <strong>of</strong> <strong>the</strong> slurry in <strong>the</strong> hopper.
The temperature very rarely went above 20°C, with a temperature <strong>of</strong> between 19°C and
20°C being <strong>the</strong> norm. A rise <strong>of</strong>.approximately 2°C is usually experienced during a test run.
If a temperature rise exceeding 2°C is experienced, data at <strong>the</strong> extreme temperatures is
compared to detect for any temperature <strong>effect</strong>s (Slatter, 1994).
3.5.4. Particle Size Distribution
The ASTM (American Standard Testing Method), which is recognized worldwide, was used
to determine <strong>the</strong> <strong>particle</strong> <strong>size</strong> <strong>distribution</strong>s and were conducted at Gibbs Africa laboratories.
In this procedure a sample <strong>of</strong> slurry is thoroughly dried and <strong>the</strong> courser <strong>particle</strong>s are screened
to determine <strong>the</strong> <strong>distribution</strong>. The <strong>distribution</strong> <strong>of</strong> finer <strong>particle</strong>s is determined using a
hydrometer. The <strong>particle</strong> <strong>size</strong> <strong>distribution</strong>s for <strong>the</strong> kaolin clay test sets however, were
determined using <strong>the</strong> Malvern 2600/3600 Particle Sizer VF.6 instrument, which if used
correctly produces more accurate results for finer material (Robertson, 1996). Ideally it
would have been preferable to use only one PSD method however, <strong>the</strong> testing method <strong>of</strong> <strong>the</strong>
Malvern instrument was not suitable for determining <strong>the</strong> courser <strong>particle</strong>s <strong>of</strong> <strong>the</strong> slurry and
hence it was decided to use <strong>the</strong> ASTM method for Mixture 1 and Mixture 2 and <strong>the</strong> Malvern
Instrument for <strong>the</strong> finer kaolin clay <strong>particle</strong>s. The <strong>particle</strong> <strong>size</strong> <strong>distribution</strong>s are presented
in Appendix A.
Any comparison <strong>of</strong> <strong>particle</strong> <strong>size</strong> <strong>distribution</strong>s should be undertaken with caution as those
prodUced by methods o<strong>the</strong>r than <strong>the</strong> ASTM or <strong>the</strong> Malvern 2600/3600 Particle Sizer VF.6
Instrument may not necessarily agree. An example <strong>of</strong> this can be seen in Figure 3.15 where
<strong>the</strong> same slurry (mixture <strong>of</strong> kaolin, rock flour and sand) used for <strong>the</strong> ASTM, was used on
<strong>the</strong> Malvern instrument for <strong>particle</strong> <strong>size</strong> <strong>distribution</strong> determjnations. As can be seen from