Quartz #4

Quartz #4 is formed by mechanical crushing of quartzite rock. Quartz Sands are denoted as #4 by its distributor AGSCO, Inc. The number 4 represents a size order, in sizes offered by the distributor, with larger numbers denoting larger sizes. The material is classified as SP according to ASTM Unified Soil Classifications System (USCS). Particles of Quartz #4 are angular as shown in Fig. 4.49. Selected DIA images of Quartz #4 are also presented in Fig. 4.50.

The Quartz sands explored in this chapter consist of 99.5% Silicone Dioxide. The balance of the constituents consists of trace amounts of Aluminum, Zirconium, Sodium, Calcium, and Iron oxides. Their specific gravity is 2.65 g/cm³.

Grain size distributions of Quartz #4 are presented using several size descriptors in Fig. 4.51. Variation between number and volume distribution is also depicted in Fig. 4.52. The size of number distribution is dominated by the finer particles while volume (i.e. mass) distribution is dominated by the larger particles. The grain size D50 of Quartz #4 is 2179 µm (by volume), which is the largest among the quartz sands investigated in this chapter. Typical particle size diameters in µm corresponding to several particle size descriptors are presented in Table 4.34. Comparison between EQPC sizes corresponding to various particle size diameters by weight/volume and number distributions are also presented in Table 4.35. A large number of finer particles were generated during the crushing process, which resulted in a marked difference between number and volume distribution calculation.Fig. 4.49. Photo of Quartz #4 sand with a 19 mm diameter US Penny for scale.

Fig. 4.49. Photo of Quartz #4 sand with a 19 mm diameter US Penny for scale.


Fig. 4.50. Images of Quartz #4 acquired using 2D DIA.

Fig. 4.50. Images of Quartz #4 acquired using 2D DIA.


Table 4.34 Typical particle size diameters in µm corresponding to several particle size descriptors (by weight/volume distribution).

Quartz #4 D1 D5 D10 D30 D50 D60 D90 D99
Feret-max 349 1409 1706 2220 2734 2991 3762 3993
EQPC 257 1023 1252 1607 2179 2547 3651 3982
Feret-min 210 798 976 1320 1561 1672 3393 3957


Table 4.35 Typical EQPC corresponding to various particle size diameters by weight/volume and number distributions.

Quartz #4 D1 D5 D10 D30 D50 D60 D90 D99
Volume 257 1023 1252 1607 2179 2547 3651 3982
Number 3 3 4 5 7 9 25 94


Table 4.36 Statistics of particle shape descriptors for Quartz #4 by number and volume distributions.

Quartz #4 AR S Cx Rwadell
Number
Mean 0.62 0.62 0.93 0.38
Median 0.63 0.61 0.93 0.38
Standard Deviation 0.14 0.09 0.03 0.08
Volume
Mean 0.63 0.62 0.93 0.38
Median 0.64 0.61 0.93 0.37
Standard Deviation 0.14 0.09 0.04 0.07


Table 4.37 Johnson fitting parameters for Quartz #4.

Quartz #4 γ δ ξ λ
AR -0.44 1.35 0.15 0.84
S 0.10 1.41 0.35 0.55
Cx 1.41 1.47 0.96 0.02
Rwadell -0.44 2.13 0.34 0.15


Fig. 4.51. Particle size distributions using various size descriptors.

Fig. 4.51. Particle size distributions using various size descriptors.

The density distribution for several commonly used shape descriptors is presented in Fig. 4.53 and summarized in Table 4.36. The distribution is clearly non gaussian and is thus fit with Johnson’s parameters. The fitting parameters are summarized in Table 4.37, and the goodness of fit is depicted in Fig. 4.54.

Fig. 4.52. Particle size volume and number distributions.

Fig. 4.52. Particle size volume and number distributions.Fig. 4.53. Particle shape density distributions (based on volume) for Quartz #4.

Fig. 4.53. Particle shape density distributions (based on volume) for Quartz #4.

Aspect Ratio - Fig. 4.54.1
Sphericity - Fig. 4.54.2
Convexity - Fig. 4.54.3
Wadell Roundness - Fig. 4.54.4

Fig. 4.54. Johnson fitting of shape descriptors for Quartz #4.