Ottawa Sand #140-270

Ottawa sand #140-270 is a naturally occurring, mechanically sorted, siliceous sand, mined from deposits near Ottawa, IL. It is the finest grade of Ottawa sand commercially available in the United States. The denotation # 140-270refers to the passing and retaining sieve sizes. The specimens tested were purchased from AGSCO corporation. The material is classified as SP according to ASTM Unified Soil Classifications System (USCS). Particles of Ottawa Sand are rounded to sub-rounded as shown in Fig. 4.43. Selected DIA images of Ottawa #140-270 are also presented in Fig. 4.44. The resolution of DIA images is 4 µm/pixel, which contributes to the inability of the device to capture edge details precisely.

Grain size distributions of Ottawa #140-270 are presented using several size descriptors in Fig. 4.45. Fig. 4.46 also depicts variation between number and volume distribution. 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 Ottawa #140-270 is 97 µm. Typical particle size diameters in µm corresponding to several particle size descriptors are presented in Table 4.30. Comparison between EQPC sizes corresponding to various particle size diameters by weight/volume and number distributions are also presented in Table 4.31.

The density distribution for a number of commonly used shape descriptors is presented in Fig. 4.47 and summarized in Table 4.32. The distribution is clearly non gaussian and is thus fit with Johnson’s parameters. The fitting parameters are summarized in Table 4.33, and the goodness of fit is depicted in Fig. 4.48.

Fig. 4.43. SEM (scanning electron microscope) image of Ottawa #140-270 sand.

Fig. 4.44. Images of Ottawa #140-270 acquired using 2D DIA.

Table 4.30 Typical particle size diameters in µm corresponding to several particle size descriptors (by weight/volume distribution).

Ottawa #140-270	D1	D5	D10	D30	D50	D60	D90	D99
Feret-max	41	68	80	104	122	131	171	222
EQPC	29	52	63	82	97	103	133	163
Feret-min	27	49	60	78	90	97	126	160

Table 4.31 Typical EQPC corresponding to various particle size diameters by weight/volume and number distributions.

Ottawa #140-270	D1	D5	D10	D30	D50	D60	D90	D99
Volume	29	52	63	82	97	103	133	163
Number	3	4	4	6	10	16	79	126

Table 4.32 Statistics of particle shape descriptors for Ottawa #140-270 by number and volume distributions.

Ottawa #140-270	AR	S	Cx	Rwadell
Number
Mean	0.73	0.75	0.89	…
Median	0.74	0.77	0.90	…
Standard Deviation	0.11	0.10	0.06	…
Volume
Mean	0.73	0.75	0.89	…
Median	0.74	0.77	0.90	…
Standard Deviation	0.11	0.10	0.06	…

Table 4.33 Johnson fitting parameters for Ottawa #140-270.

Ottawa #140-270	γ	δ	ξ	λ
AR	-0.66	1.35	0.32	0.67
S	-1.95	1.31	0.13	0.78
Cx	1.34	1.14	0.93	0.02
Rwadell	…	…	…	…

Fig. 4.45. Particle size distributions using various size descriptors.

Fig. 4.46. Particle size volume and number distributions.

Fig. 4.47. Particle shape density distributions (based on volume) for Ottawa #140-270.

Fig. 4.48. Johnson fitting of shape descriptors for Ottawa #140-270.