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

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 1Level 2Level 3
Pre-dried particle density Number of laboratories included N181918
Average X2.703.062.60
Repeatability standard deviation Sr10.00280.00560.0030
Reproducibility standard deviation SR10.00670.00940.0134
Critical range Wc0.0100.0210.012
Repeatability limit r10.0080.0160.009
Reproducibility limit R10.0190.0260.037
SSD particle densityNumber of laboratories included N191919
Average X2.673.052.51
Repeatability standard deviation Sr10.00270.00580.0059
Reproducibility standard deviation SR10.00410.00890.0092
Repeatability limit r10.0080.0160.017
Reproducibility limit R10.0120.0250.026
Water absorptionNumber of laboratories included N191916
Average X1.00.53.1
Repeatability standard deviation Sr10.0610.0470.084
Reproducibility standard deviation SR10.1010.1120.222
Repeatability limit r10.170.130.24
Reproducibility limit R10.280.310.62

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 Sr1 = 0042 (1)
Reproducibility standard deviation SR1 = 0.0081 (1)
Repeatability limit r1 = 0.012 (1)
Reproducibility limit R1 = 0.023 (1)
SSD particle densityRepeatability standard deviation Sr1 = 0.0048 (2)
Reproducibility standard deviation SR1 = 0.0074 (2)
Repeatability limit r1 = 0.014 (2)
Reproducibility limit R1 = 0.021 (2)
Water absorptionRepeatability standard deviation Sr1 = 0.043 + 0.0138 X
Reproducibility standard deviation SR1 = 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 1Level 2Level 3
Pre-driedRepeatability coefficient of variation Cr10.100.180.12
Reproducibility coefficient of variation CR10.250.310.51
SSDRepeatability coefficient of variation Cr10.100.190.24
Reproducibility coefficient of variation CR10.150.290.36
WARepeatability coefficient of variation Cr16.09.62.7
Reproducibility coefficient of variation CR110.022.97.1