The CTPT3 Workability Tester
from Aptifirst is designed to
automatically measure the
workability of fresh (wet) cement
pastes and concrete mortars.

Traditionally, workability is
measured using the Slump Test – a
standardised bucket that is filled with
the specimen, inverted and the
amount by which the sample slumps
measured. Whilst useful for batch-tobatch
comparisons, this does not
provide engineering information
about the flow properties, or rheology.

The CTPT3 has a helical impeller
driven by a state-of-the-art servodrive
system, which is immersed in a
sample of around 20 litres. The
impeller is rotated over a range of
speeds and the torque required to stir
the material at each speed is recorded
using a purpose-designed, radiotelemetry,
rugged torque transducer
mounted directly above the impeller.

A computer system controls the
speed and records and displays the
torque, and will analyse and store the
data, removing much operator
variability.