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New Improved CTPT2 now available!
for Fresh Cement, Concrete and Other Materials    
Download the datasheet for the CTPT2 computer controlled, two-point workability test rheometer for fresh wet cement and concrete  
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Fresh cement and concrete pastes have been shown to behave as Bingham fluids, that is to say that they do not flow until a characteristic Yield Stress has been exceeded. After this yield stress, they flow in a linear manner, with the shear stress being proportional to the shear rate. The level of the yield stress and the degree of proportionality between yield stress and shear rate (ie the plastic viscosity) are functions of processing parameters such as water content, sand to cement ratio and the amount and type of aggregate present.

If these parameters could be measured for each batch of fresh concrete, a pattern could be established of which batches were acceptable and which caused problems. In the 1970s, Dr G H Tattersall, working at the Centre for Cement and Concrete at the University of Sheffield, designed a rugged machine which would establish the two characteristic parameters. We have considerably improved the machine by adding state-of-the art automation in order to eliminate some operator variables of earlier versions, and have built in full guarding to protect the operator.

The sample, of about 20 to 30 litres, is contained in a steel bucket. An impeller (of which there are several geometries) is rotated in the mix at a series of controlled speeds, and the torque required to mix at each speed is displayed on a pressure gauge and recorded electronically. A planetary drive is available to avoid problems due to cavitation. A purpose-written computer programme analyses the data and determines the characteristic Yield Stress intercept and the Slope of the torque vs speed graph.

The CTPT is available in a Laboratory version, with separate PC system. A Site version with an embedded computer and industrial display is planned. The machine may be programmed to run a "standard" test with ramped speed, or may be run at constant speed or at a series of constant speeds. The instrument is extremely useful in formulation development, quality control, troubleshooting, and for research applications.

 

 

Key features of the CTPT2:

Automatic, instrumented two-point workability test for fresh cement and concrete Robust, welded-frame construction
Automatic, instrumented two-point workability test for fresh cement and concrete State-of-the art servomotor drive
Automatic, instrumented two-point workability test for fresh cement and concrete Contactless independent torque sensor
Automatic, instrumented two-point workability test for fresh cement and concrete Electrically interlocked guards
Automatic, instrumented two-point workability test for fresh cement and concrete Automatic control of speed of rotation
Automatic, instrumented two-point workability test for fresh cement and concrete Impellers may be fitted centrally or via planetary gear
Automatic, instrumented two-point workability test for fresh cement and concrete Sample container mounted on wheels to ease loading & improve safety
Automatic, instrumented two-point workability test for fresh cement and concrete Stainless steel impellers available as an option
Automatic, instrumented two-point workability test for fresh cement and concrete Suitable for R & D, troubleshooting and QA/QC
Automatic, instrumented two-point workability test for fresh cement and concrete Impeller speeds <0.01 rpm to 120 rpm
Automatic, instrumented two-point workability test for fresh cement and concrete
Torque to 30 Nm
Automatic, instrumented two-point workability test for fresh cement and concrete
Torque measured electronically
Automatic, instrumented two-point workability test for fresh cement and concrete Speed profile may be ramped or stepped,
      constant or manually varied

Automatic, instrumented two-point workability test for fresh cement and concrete Working parts may be cleaned with hose
Automatic, instrumented two-point workability test for fresh cement and concrete Powered from single phase 230V 50Hz.
    110/120V 60Hz available also

Automatic, instrumented two-point workability test for fresh cement and concrete Computer system logs data and analyses rapidly
Automatic, instrumented two-point workability test for fresh cement and concrete CTPVT Version allows Vane Test too.

We are always happy to quote for special modifications to suit your needs

Download the datasheet for the CTPT2 Two-Point Workability Test Rheometer for Fresh Wet Cement and Concrete

 

CTPT2 Automatic Two Point Workability Test Rheometer for Fresh Wet Cement Concrete and Other Materials

CTPT2 Two Point Workability Test

Different types of generic shear flows; Newtonian, Pseudoplastic or shear-thinning, Dilatant or shear-thickening, Bingham or plastic, and Herschel-Bulkley
To show different types of flow behaviour that have been observed for different materials. Cement based materials tend to be Bingham Fluids.

Plot of CTPT2 raw data for a sand and cement mortar, showing the preprogrammed "staircase" speed profile and the resultant torque.

Effects of the addition of superplasticiser and water to a cement mortar as determined by the CTPT2 Two Point Workability Test Rheometer from Celsum Technologies

Effects on the Flow Curve of the addition of Water and Superplasticiser

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Page last updated 15th June 2009
Specifications subject to change without notice
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