Testing of industrial products - Aggregates for construction

Precision values obtained from the cross-testing experiment on the determination of Particle Density and Water Absorption of Coarse Aggregates

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Note. For all the tables here, "stragglers" have been included in the calculations, and "outliers" have been excluded.

Table 1. Repeatability and reproducibility values for determinations of particle density (Mg/m³) and water absorption (%) of coarse aggregate.
			Level 1	Level 2	Level 3
Pre-dried particle density	Number of laboratories included	N	18	19	18
	Average	X	2.70	3.06	2.60
	Repeatability standard deviation	S_r1	0.0028	0.0056	0.0030
	Reproducibility standard deviation	S_R1	0.0067	0.0094	0.0134
	Critical range	W_c	0.010	0.021	0.012
	Repeatability limit	r₁	0.008	0.016	0.009
	Reproducibility limit	R₁	0.019	0.026	0.037
SSD particle density	Number of laboratories included	N	19	19	19
	Average	X	2.67	3.05	2.51
	Repeatability standard deviation	S_r1	0.0027	0.0058	0.0059
	Reproducibility standard deviation	S_R1	0.0041	0.0089	0.0092
	Repeatability limit	r₁	0.008	0.016	0.017
	Reproducibility limit	R₁	0.012	0.025	0.026
Water absorption	Number of laboratories included	N	19	19	16
	Average	X	1.0	0.5	3.1
	Repeatability standard deviation	S_r1	0.061	0.047	0.084
	Reproducibility standard deviation	S_R1	0.101	0.112	0.222
	Repeatability limit	r₁	0.17	0.13	0.24
	Reproducibility limit	R₁	0.28	0.31	0.62

Table 2. Functional relations for determinations of particle density (Mg/m³) and water absorption (%) of coarse aggregate.
		Functional relationship
Pre-dried particle density	Repeatability standard deviation	S_r1 = 0042 (1)
	Reproducibility standard deviation	S_R1 = 0.0081 (1)
	Repeatability limit	r₁ = 0.012 (1)
	Reproducibility limit	R₁ = 0.023 (1)
SSD particle density	Repeatability standard deviation	S_r1 = 0.0048 (2)
	Reproducibility standard deviation	S_R1 = 0.0074 (2)
	Repeatability limit	r₁ = 0.014 (2)
	Reproducibility limit	R₁ = 0.021 (2)
Water absorption	Repeatability standard deviation	S_r1 = 0.043 + 0.0138 X
	Reproducibility standard deviation	S_R1 = 0.080 + 0.0414 X
	Repeatability limit	r₁ = 0.12 + 0.039 X
	Reproducibility limit	R₁ = 0.22 + 0.116 X

(1) Average values for Levels 1 and 2 (water absorptions 1.0 % and 0.5 %).

(2) Average values for Levels 1, 2 and 3.

Table 3. Repeatability and reproducibility standard deviations expressed as coefficients of variation.
			Level 1	Level 2	Level 3
Pre-dried	Repeatability coefficient of variation	C_r1	0.10	0.18	0.12
	Reproducibility coefficient of variation	C_R1	0.25	0.31	0.51
SSD	Repeatability coefficient of variation	C_r1	0.10	0.19	0.24
	Reproducibility coefficient of variation	C_R1	0.15	0.29	0.36
WA	Repeatability coefficient of variation	C_r1	6.0	9.6	2.7
	Reproducibility coefficient of variation	C_R1	10.0	22.9	7.1