Measuring and testing – Liquid analysis or analysis of the suspension of solids in a... – Viscosity
Patent
1989-03-30
1990-06-05
Williams, Hezron E.
Measuring and testing
Liquid analysis or analysis of the suspension of solids in a...
Viscosity
73815, G01N 1114, G01N 3338
Patent
active
049303465
DESCRIPTION:
BRIEF SUMMARY
A method for the determination of the properties of mouldable materials, particularly for the determination of the plastic and reologic properties thereof:
BACKGROUND OF THE INVENTION
This invention relates to a method for the determination of the properties of mouldable materials, such as the granular and pulverous masses of fresh concrete, and stiff liquids, particularly for the determination of the plastic and reologic properties thereof, in which method therefor are determined.
Bingham's theory on the interdependence between the resistance to deformation and the shear speed of a material can be applied to plastic materials, such as concrete. According to this theory a plastic material has a yield ratio, i.e. a determined minimum shear stress, which is required for obtaining a permanent deformation, and a plastic viscosity dependent on the shear speed.
The measurement of the plastic and reologic properties, such as the yield ratio and the plastic viscosity, would be useful, because the behaviour of concrete both with respect to the castability and the compactibility thereof can be assessed by means of these values. Since the slump of a concrete cone is generally used to describe castability, it has to be taken into account that when using activated plasticizers or silica, the slump value has to be greater than in cases where these additives are not used if the same workability is to be achieved. This is due to the fact that such additives increase the plastic viscosity but not the yield ratio. In other words, concrete containing e.g. silica possesses a normal resistance to deformation at low speeds in slump measurements, but a high resistance at shear speeds occurring during vibration.
For measuring the plastic and reologic properties of plastic concrete masses with different shear speeds, a method is known in which concrete resting freely in a vessel is mixed with several different speeds and the force resisting the mixing is measured. The poorly controlled flows make it necessary to use a nonlinear speed scale. Thereby the shear speed field, too, is strongly non-homogenenous, and no accurate result can be obtained by the measurement if the concretes deviate greatly from each other. Consequently, not even plastic concrete masses can be measured reliably by means of this method.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a method which avoids the above disadvantages and enables a more accurate measuring of the plastic and reologic properties of mouldable materials. This object is achieved by means of a method according to the invention which is characterized in that the sample is compressed in two opposite directions with a constant force; the sample is moulded under a constant compression between two parallel inclined planes which change position by revolving; the volume of the sample is measured prior to the compaction and after a determined number of working revolutions; and the magnitude of the torque resisting the revolving of the inclined planes is measured at least at one determined shear speed of the sample, which speed depends on the revolving speed of the inclined planes and the angle of incline thereof.
The invention is based on the concept that the determination of the plastic and reologic properties of a concrete mass is carried out by machine under accurately similar circumstances reproduceable for individual samples, whereby the information obtained on these properties is always reliable.
During the measuring process the shear speeds of the sample are accurately determined and homogenenous. This makes it possible to measure concrete samples in such a way that the obtained results are reliably reproduceable and physically controllable in view of the assessment of concrete.
By virtue of the method according to the invention it is possible to immediately alter the composition of the concrete mass to be prepared in a concrete mixer on the basis of the plastic and reologic properties measured from the sample so that the properties of a cast product will be
REFERENCES:
patent: 4095461 (1978-06-01), Starita
patent: 4343190 (1982-08-01), Danko et al.
Nordenswan Erik T.
Paakkinen Ilmari
Rantanen Heikki O.
Paakkinen Ilmari
Roskos Joseph W.
Williams Hezron E.
LandOfFree
Method for the determination of the properties of mouldable mate does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for the determination of the properties of mouldable mate, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for the determination of the properties of mouldable mate will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-484363