The SANS 50196-3:2006 method of testing cement was used to determine the standard consistence and setting time of the three cement paste mixtures. This method is used to assess whether the setting time of particular cement is in conformity with its specification. The method for mixing the pastes is clearly defined in standard method and the standard consistence is determined through trial and error to give the w/b ratio to be used in the initial and final setting time tests. The initial and final setting tests are conducted through penetration of a sample at standard consistence with the use of a manual Vicat, which can be seen in the image below.

 

A summary of the standard test method is as follows:

 

An automatic mixer was used to prepare samples using 500 grams of binder and varied amounts of water to determine the standard consistence. Once the w/b ratio had been determined at standard consistence, by plunger depth penetration, samples for setting time tests could be prepared. The initial setting time test was conducted by needle penetration at appropriately spaced time intervals (±10 min), which commenced at ±2 h after wetting of binder and was terminated once a depth of 6 mm (±3 mm) was achieved between the needle and the base plate of the Vicat. Final setting time was determined by measuring the depth of penetration on the inverse surface of the sample used for the initial setting time test. Again the test was conducted at appropriately spaced time intervals (±30 min), which commenced at ±3 h after wetting of binder and was terminated once the final setting time needle penetrated the sample by only 0.5 mm, which is indicated when no marking by the final setting time needle attachment was seen on the surface of the sample.