The Slump Test is the most widely-used method of measuring the
workability of fresh concrete. This involves sampling concrete directly from a readymix truck which wastes many thousands of cubic metres of the material that should be poured into the building or structure. This paper outlines the development of a Probe (a sensor) that can be mounted into the drum of a ready-mix concrete truck to monitor the concrete workability in real time. It can also measure the concrete temperature, drum speed and the volume of concrete in the drum.
The workability is first assessed by measuring the normal pressure applied on the
Probe by the concrete inside the drum while the drum is turning. Then by measuring
that pressure at different speed, one can get a rheological profile from which
viscosity and yield stress can be determined and hence the Slump of the concrete
can be estimated with a reasonable degree of accuracy.
This data can be checked on a display mounted directly onto the truck or sent to a
remote monitoring location. This paper also discusses some aspects of the