Quartz #2

Quartz #2 is obtained by crushing quartzite rock mechanically, and it is classified as SP based on the ASTM Unified Soil Classifications System. AGSCO, Inc denotes it as #2, which signifies its size order, in the quartz sands offered. The particles of Quartz #2 are angular in shape, as indicated in Fig. 4.61, and selected DIA images are presented in Fig. 4.56.

The grain size distributions of Quartz #2 are depicted in Fig. 4.63 using various size descriptors, and the variation between the number and volume distribution is shown in Fig. 4.64. The size of number distribution is dominated by the finer particles while volume distribution is dominated by the larger particles. The grain size D₅₀ of Quartz #2 is 400 µm. Typical particle size diameters in µm corresponding to several particle size descriptors are presented in Table 4.42. Comparison between EQPC sizes corresponding to various particle size diameters by weight/volume and number distributions are also presented in Table 4.43. A large number of finer particles were generated during the crushing process, which resulted in a difference between number and volume distribution calculation.

The density distribution for a number of commonly used shape descriptors is presented in Fig. 4.65 and summarized in Table 4.44. The distribution is clearly non gaussian and is thus fit with Johnson’s parameters. The fitting parameters are summarized in Table 4.45, and the goodness of fit is depicted in Fig. 4.66.

Fig. 4.61. Photo of Quartz #2 sand with a 19 mm diameter US Penny for scale.

Fig. 4.62. Images of Quartz #2 acquired using 2D DIA.

Table 4.42 Typical particle size diameters in µm corresponding to several particle size descriptors (by weight/volume distribution).

Quartz #2	D1	D5	D10	D30	D50	D60	D90	D99
Feret-max	62	185	297	454	563	615	855	1152
EQPC	44	132	209	325	400	437	589	735
Feret-min	41	108	166	262	326	357	496	626

Table 4.43 Typical EQPC corresponding to various particle size diameters by weight/volume and number distributions.

Quartz #2	D1	D5	D10	D30	D50	D60	D90	D99
Volume	44	132	209	325	400	437	589	735
Number	3	4	4	6	8	10	26	136

Table 4.44 Statistics of particle shape descriptors for Quartz #2 by number and volume distributions.

Quartz #2	AR	S	Cx	Rwadell
Number
Mean	0.59	0.70	0.90	0.59
Median	0.60	0.72	0.91	0.59
Standard Deviation	0.15	0.10	0.05	0.13
Volume
Mean	0.60	0.71	0.91	0.57
Median	0.60	0.73	0.92	0.57
Standard Deviation	0.15	0.09	0.04	0.12

Table 4.45 Johnson fitting parameters for Quartz #2.

Quartz #2	γ	δ	ξ	λ
AR	-0.24	1.25	0.14	0.85
S	-3.46	1.90	-0.46	1.37
Cx	1.86	1.57	0.96	0.03
Rwadell	2.80	4.54	0.88	0.47

Fig. 4.63. Particle size distributions using various size descriptors.

Fig. 4.64. Particle size volume and number distributions.

Fig. 4.65. Particle shape density distributions (based on volume) for Quartz #2.

Fig. 4.66. Johnson fitting of shape descriptors for Quartz #2.