Ottawa Sand #70-100

Ottawa sand #70-100 is a naturally occurring, mechanically sorted, siliceous sands, mined from deposits near Ottawa, IL. It is commonly used as a graded standard sand in the United States and denoted by the numbers 70-100. The denotation refers 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 shown in Fig. 4.31. Selected DIA images of Ottawa #70-100 are also presented in Fig. 4.32. The DIA images help show that particles of Ottawa #70-100 are rounded to sub-rounded.

Grain size distributions of Ottawa #70-100 are presented using several size descriptors in Fig. 4.33. Fig. 4.34 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 #70-100 is 287 µm. Typical particle size diameters in µm corresponding to several particle size descriptors are presented in Table 4.22. Comparison between EQPC sizes corresponding to various particle size diameters by weight/volume and number distributions are also presented in Table 4.23.

The density distribution for a number of commonly used shape descriptors is presented in Fig. 4.35 and summarized in Table 4.24. The distribution is clearly non gaussian and is thus fit with Johnson’s parameters. The fitting parameters are summarized in Table 4.25, and the goodness of fit is depicted in Fig. 4.36.

Fig. 4.31. Photo of Ottawa #70-100 sand with a 19 mm diameter US Penny for scale.

Fig. 4.32. Images of Ottawa #70-100 acquired using 2D DIA.

Table 4.22 Typical particle size diameters in µm corresponding to several particle size descriptors (by weight/volume distribution).

Ottawa #70-100	D1	D5	D10	D30	D50	D60	D90	D99
Feret-max	194	241	267	320	353	372	434	529
EQPC	153	192	216	261	287	302	352	429
Feret-min	135	171	192	233	261	273	332	388

Table 4.23 Typical EQPC corresponding to various particle size diameters by weight/volume and number distributions.

Ottawa #70-100	D1	D5	D10	D30	D50	D60	D90	D99
Volume	153	192	216	261	287	302	352	429
Number	3	3	4	5	8	10	223	345

Table 4.24 Statistics of particle shape descriptors for Ottawa #70-100 by number and volume distributions.

Ottawa #70-100	AR	S	Cx	Rwadell
Number
Mean	0.74	0.76	0.92	0.75
Median	0.75	0.78	0.93	0.76
Standard Deviation	0.10	0.10	0.04	0.10
Volume
Mean	0.74	0.76	0.93	0.75
Median	0.75	0.78	0.93	0.76
Standard Deviation	0.10	0.10	0.03	0.10

Table 4.25 Johnson fitting parameters for Ottawa #70-100.

Ottawa #70-100	γ	δ	ξ	λ
AR	-1.03	1.61	0.26	0.76
S	6.46	2.50	0.99	0.03
Cx	0.92	1.09	0.95	0.02
Rwadell	-5.43	3.49	-1.14	2.30

Fig. 4.33. Particle size distributions using various size descriptors.

Fig. 4.34. Particle size volume and number distributions.

Fig. 4.35. Particle shape density distributions (based on volume) for Ottawa #70-100.

Fig. 4.36. Johnson fitting of shape descriptors for Ottawa #70-100.