The test consists to determinate flexural strength of mortar samples after a certain period of curing at temperature of 21 ± 2°C and relative humidity of 60 ± 10%. The described method can be applied to all types of mortar having an aggregate with a maximum size of 8mm.
The test is carried out on three prismatic test of size 40mm x 40mm x 160 mm, that are prepared by mechanical mixer and compacted by a jolting machine or a pestle. The instrument used to perform this test is an automatic hydraulic press with a capacity of 15 kN. To determine the value of the flexural strength it is necessary to position the prism (40mm x 40mm x 160 mm) in the flexural device, with a side face on the supporting rollers and with its longitudinal normal axis on the supports. It is always a good rule to positionate the face of the sample, that in the mold preparation step it was in contact to air, on the supporting rollers towards the outside of the machine, and then in front of the operator. The test is performed by applying a vertical load by means of the loading roller on the side face of the prism and uniformly increasing the speed of (50 ± 10) N/s until breaking. During the test, on the monitor you can see the progress graph of time/force applied (s/kN) or time/stress (s/MPa). The highest value read on the graph represents the flexural strength of the sample under test.
The result of the flexural test is evaluated by calculating the arithmetic mean of the three individual results, each of which must be expressed to the nearest 0.1MPa.

 

Material type Standard Test method
finishing plasters EN 998-1
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gypsum-based plasters EN 13279-1
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screeds EN 13813
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self-levelings EN 13813
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restoring mortars EN 1504-3
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grouting mortars EN 13888
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cements EN 197-1
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surface protection mortars EN 1504-2
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Instruments used to perform the test: Press for cements