FRF Sand

FRF is a sediment obtained from the US Army Corps of Engineers Field Research Facility at Duck, North Carolina. FRF sand is classified as a mixture of sub-angular and sub-rounded particles, as shown in Fig. 4.103. Selected DIA images of FRF are also presented in Fig. 4.104.

Grain size distributions of FRF sand are presented using several size descriptors in Fig. 4.105. Fig. 4.106 also depicts variation between number and volume distribution. The size of the number distribution is dominated by the finer particles while volume distribution is dominated by the larger particles. The grain size D₅₀ of FRF is 341µm. Typical particle size diameters in µm corresponding to several particle size descriptors are presented in Table 4.70. Comparison between EQPC sizes corresponding to various particle size diameters by weight/volume and number distributions are also presented in Table 4.71.

The density distribution for a number of commonly used shape descriptors is presented in Fig. 4.107 and summarized in Table 4.72. The distribution is clearly non gaussian and is thus fit with Johnson’s parameters. The fitting parameters are summarized in Table 4.73, and the goodness of fit is depicted in Fig. 4.108.

Fig. 4.103. Photo of FRF sand with a 19 mm diameter US Penny for scale.

Fig. 4.104. Images of FRF acquired using 2D DIA.

Table 4.70 Typical particle size diameters in µm corresponding to several particle size descriptors (by weight/volume distribution).

FRF	D1	D5	D10	D30	D50	D60	D90	D99
Feret-max	207	263	292	361	414	447	589	825
EQPC	171	214	246	295	341	364	472	618
Feret-min	153	194	210	264	300	318	406	527

Table 4.71 Typical EQPC corresponding to various particle size diameters by weight/volume and number distributions.

FRF	D1	D5	D10	D30	D50	D60	D90	D99
Volume	171	214	246	295	341	364	472	618
Number	3	4	4	6	9	11	253	408

Table 4.72 Statistics of particle shape descriptors for FRF by number and volume distributions.

FRF	AR	S	Cx	Rwadell
Number
Mean	0.73	0.85	0.95	0.73
Median	0.74	0.86	0.95	0.74
Standard Deviation	0.10	0.05	0.02	0.09
Volume
Mean	0.74	0.85	0.95	0.75
Median	0.75	0.86	0.95	0.76
Standard Deviation	0.10	0.05	0.02	0.09

Table 4.73 Johnson fitting parameters for FRF.

FRF	γ	δ	ξ	λ
AR	-0.63	1.30	0.36	0.62
S	1.17	1.24	0.90	0.03
Cx	2.82	1.89	0.98	0.01
Rwadell	-1.04	1.49	0.30	0.66

Fig. 4.105. Particle size distributions using various size descriptors.

Fig. 4.106. Particle size volume and number distributions.

Fig. 4.107. Particle shape density distributions (based on volume) for FRF.

Fig. 4.108. Johnson fitting of shape descriptors for FRF.