Consistence tolerance

Consistence tolerance - slump test

Consistence, measured using the slump test (BS EN 12350-2), is either specified as a class or target. Although a supplier will endeavour to provide the required value or range, deviations in production and sampling apply. The following tables give the maximum allowable deviation based on a spot sample taken from the initial discharge of a ready-mixed concrete truck.

Class
Slump range
Max. allowable deviation on
range limit (mm)

S1 10 - 40 0 - 60

S2
50 - 90
30 - 110

S3 100 - 150 80 - 170

S4 160 - 210 140 - 230

Due to lack of sensitivity of slump test values less than 10mm or greater than 210mm, it recomended to only use the test for slump ≥10mm and ≤210mm

Target slump (mm)
Max. allowable deviation on
target value (mm)

≤ 40
± 30

50 - 90
± 40

≥ 100
± 50

Based on BS 8500-1:2015 +A1: 2016

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