This test is conducted using a cement-mortar briquette in a tensile testing machine. The dimensions of the briquette are shown in Fig. 6.8.
Figure 6.8 Standard cement-mortar briquette
A 1:3 cement–sand mortar with water content of 8% is mixed and moulded into a briquette in the mould. It is cured for 24 hours at a temperature of 27 ± 2°C and for 24 hours in an atmosphere at 90% relative humidity.
The briquette is tested under direct tension, the pull being applied through special jaws engaging the wide ends of the briquette. The area of cross-section at the neck is 1 sq inch (i.e., 25.4 mm × 25.4 mm). The average strength for six briquettes tested after 3 and 7 days is recorded.
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