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Pheso Rheometer
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Like all Calmetrix instruments, Pheso was designed by real users from the world of research and development. As a result, it combines all the practical elements making it well adapted and easy to use in the cement and concrete industry. 


Pheso features a proprietary software and computer-controlled motion with direct measurement of torque up to 160 Nm at an accuracy of +/- 0.01 Nm. The robust design makes this equipment suitable both for a laboratory environment and on job sites or plant environments where daily quality control is necessary. 


The Pheso rheometer was designed and developed by true concrete research professionals and therefore incorporates design elements that are typically missing from other alternatives in the market. Pheso is exceptionally versatile, as its torque range is suitable for soft & stiff suspensions, from liquids all the way to dry powder materials in sample volumes anywhere from 1 liter to 20 liters. With options to operate in either central or planetary mode, and interchangeable impellers, users have access to all the flexibility allowing them to measure different material characteristics in cement paste, mortar or concrete, in high or low fluidity, including “0 slump” concrete, as well as dry materials or fibrous suspensions. The operation in planetary mode and the high shear mixing using the attritor shaped impeller allow for long term testing without segregation in a realistic simulation of field conditions. One can emulate the entire chain of events from the batch process at the concrete plant through delivery and placement at the job site. Long term testing for several hours can be conducted without interruption as mixing occurs directly in the Pheso rheometer, concurrently with the rheological measurement, such that rheology is measured in the exact sequence of mixing, without the need to transfer material from outside mixers. A convenient software interface allows users to program mixing and test routines with a customized rotation speed and duration for each step, to easily obtain flow test, stress growth test, and shearing cycle curves.




Pheso can be used to study rheological parameters such as mixing profiles, shearing profiles and mixing energy in a wide range of situations and mix designs, including cement paste, mortar or real concrete in soft and stiff suspensions, as well as dry or fibrous materials. Typical applications:

  • assess the effect of different shapes of aggregates, or different size distributions,  on rheology

  • study the impact of different chemical admixtures (air entraining agents, plasticizers, retarders) and their interaction with other materials such as supplementary cementitious materials or fibers

  • compare the effectiveness and ease of placement of different specialty mortars

  • long-term studies of rheological behavior from initial mixing to delivery on the job site

  • determine the optimum dosage, addition time and mixing time for self-consolidating concrete

  • measure the effect of water addition or admixture addition rate on concrete rheology

  • quality control of concrete mixes, mix design optimization, selection of raw materials, etc.

  • find the optimum mixing sequence for concrete with fibers (when to add the fibers)



When to consider a Pheso rheometer:

Pheso is the right rheometer if you conduct research, development or quality control involving:

  • granular or inhomogeneous mixtures like concrete or mortar

  • mixes that require high shear or mixing energy

  • a wide variety of materials from very stiff to very fluid

  • samples with granules such as aggregates that segregate in other rheology tests

  • fibrous suspensions (steel or plastic fibers)

  • stiff concrete, including pervious or "zero-slump" concrete

  • long-term rheology testing (up to several hours) 

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