Schleibinger Testing Systems - ASTM-Shrinkage Ring

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ASTM-Shrinkage Ring

Measuring the Restrained Shrinkage According to ASTM C1581

"Standard Test Method for Determining Age at Cracking and Induced Tensile Stress
Characteristics of Mortar and Concrete under Restrained Shrinkage"

This test method covers the laboratory determination of the age at cracking and induced tensile stress characteristics of mortar or concrete specimens under restrained shrinkage. The procedure can be used to determine the effects of variations in the proportions and material properties of mortar or concrete on cracking due to both drying shrinkage and deformations caused by autogenous shrinkage and heat of hydration.

A sample of freshly mixed mortar or concrete is compacted in a circular mold around an instrumented steel ring. The compressive strain developed in the steel ring caused by shrinkage of the mortar or concrete specimen is measured with 4 strain gages from the time of casting. Cracking of the test specimen is indicated by a sudden decrease in the steel ring strain. The age at cracking and the rate of tensile stress development in the test specimen are indicators of the materials resistance to cracking under restrained shrinkage (cited from the standard).

Steel ring strain vs. time. The specimen is cracking after 6.8 days at a strain of about 100 µm/m : ASTM C1581

If you want use bigger aggregates up to 20 mm we recommend the Schleibinger AASHTO Ring. Near the same design, but a bigger Volume of 13.83 l = 3.65 US Gallons.

On each steel ring a strain-gage amplifier and one thermocouple type K input is mounted. The data of up to 6 rings are digitally transferred to the data-logger.

A data-logger supplied with the system records strain gage data and temperature and store it in the logger as standard ASCII files. Optional a synchronous registration of the environmental temperature and humidity is possible.

The logger has a network interface (Ethernet). So you can easily integrate it into local intranet. With a standard web-browser software you can readout the data and visualize it. For further data handling we recommend Microsoft Excel ® ore any similar visualization program. The data are visualized online graphical and numerical on the screen. No special PC software is necessary. You need only your browser-software like Firefox, Chrome, Edge, Opera ® . Operating system Windows, MacOS, Android, Linux.

Literature:

Shrinkage Ring Order code: S00031:

ASTM Shrinkage ring made of steel (1.0570) with 4 strain gages. Thickness 13 mm, outer diameter 330 mm, height 150 mm, weight 15.5 kg. Other sizes on request.
Strain gage amplifier, thermocouple type K input and digitizing unit, mounted inside the inner ring. Serial digital SMB bus interface to the data logger S0003.
Outer ring made of stainless steel. Inner diameter 406 mm, height 150 mm.
Specimen volume ca. 6.6 liters (1.74 US.liq.gal.). Specimen thickness ca. 35.5 mm. For bigger size, please check the AASHTO-Ring.
Base made of PP. 480 x 480 x 20 mm³
Bolts, nuts and washers for fixing the rings on the ground plate.
Stainless steel ring for covering the specimen.