Quantifying Repeatability Reproducibility Sources of Error and Capacity of a Measurement: Demonstrated Using Laboratory Soil Plasticity Tests

Table 1

Trough designs and drying methods for various BLS testing standards.

Parameter	South Africa TMH1 A4	British standard BS1377	Australia P6A/1	Texas 107-E	California CTM-228
Cross-section shape	Square	Semicircular	Semicircular	Square	Tapered
Cross-section dimension (mm)	10 × 10	25 diameter	25 diameter	19 × 19	Top width 19.05, bottom width 17.48
Length (mm)	150	140	135 or 250	127	127
Drying method	Oven dry (110°C)	Air dry + oven dry (65 and 110°C)^a	Air dry (24 h) + oven dry (110°C)	Air dry^b + oven dry (110°C)	Air dry^b + oven dry (110°C)

^aPlace the mold where the soil/water can air-dry slowly in a position free from drafts until the soil has shrunk away from the walls of the mold. Then complete the drying, first at a temperature not exceeding 65°C until shrinkage has largely ceased and then at 105°C to 110°C to complete the drying. ^bAir-dry the soil bar at room temperature until color changes slightly.