Ottawa Sand #35-50

Ottawa sand #35-50 is a naturally occurring, mechanically sorted, siliceous sand, mined from deposits near Ottawa, IL. It is commonly used as a graded standard sand in the United States and denoted by the numbers 35-50. 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 are rounded as shown in Fig. 4.13. Selected DIA images of Ottawa #35-50 are also presented in Fig. 4.14.

Grain size distributions of Ottawa #35-50 are presented using several size descriptors in Fig. 4.15. Fig. 4.16 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 #35-50 is 557 µm. Typical particle size diameters in µm corresponding to several particle size descriptors are presented in Table 4.10. Comparison between EQPC sizes corresponding to various particle size diameters by weight/volume and number distributions are also presented in Table 4.11.

The density distribution for a number of commonly used shape descriptors is presented in Fig. 4.17 and summarized in Table 4.12. The distribution is clearly non-Gaussian and is thus fit with Johnson’s parameters. The fitting parameters are summarized in Table 4.13, and the goodness of fit is depicted in Fig. 4.18.

Fig. 4.13. Photo of Ottawa #35-50 sand with a 19 mm diameter US Penny for scale.

Fig. 4.14. Images of Ottawa #35-50 acquired using 2D DIA.

Table 4.10 Typical particle size diameters in µm corresponding to several particle size descriptors (by weight/volume distribution).

Ottawa #35-50	D1	D5	D10	D30	D50	D60	D90	D99
Feret-max	427	481	533	600	666	697	822	1001
EQPC	353	412	446	503	557	582	697	907
Feret-min	301	360	379	448	495	518	628	778

Table 4.11 EQPC corresponding to various particle size diameters by weight/volume and number distributions.

Ottawa #35-50	D1	D5	D10	D30	D50	D60	D90	D99
Volume	353	412	446	503	557	582	697	907
Number	3	3	4	5	7	9	26	612

Table 4.12 Statistics of particle shape descriptors for Ottawa #35-50 by number and volume distributions.

Ottawa #35-50	AR	S	Cx	Rwadell
Number
Mean	0.74	0.87	0.96	0.76
Median	0.76	0.88	0.97	0.77
Standard Deviation	0.10	0.05	0.02	0.08
Volume
Mean	0.74	0.86	0.96	0.77
Median	0.75	0.88	0.97	0.77
Standard Deviation	0.10	0.05	0.02	0.08

Table 4.13 Johnson fitting parameters for Ottawa #35-50.

Ottawa #35-50	γ	δ	ξ	λ
AR	-2.38	2.10	-0.21	1.27
S	1.10	0.94	0.91	0.02
Cx	0.90	0.73	0.98	0.00
Rwadell	-0.93	1.851	0.38	0.63

Fig. 4.15. Particle size distributions using various size descriptors.

Fig. 4.16. Particle size volume and number distributions.

Fig. 4.17. Particle shape density distributions (based on volume) for Ottawa #35-50.

Fig. 4.18. Johnson fitting of shape descriptors for Ottawa #35-50.