The effects of lime and admixtures on the water-retaining properties of cement mortars

The water-retaining properties of wet mortar mixes are examined. The desorptivity is defined as a parameter characterising the water-retaining properties of such mixes. A test method based on the American Petroleum Institute filtration cell is described for measuring the desorptivity of wet mixes. Experimental results are reported for a range of wet cement mortars including mixes containing lime and air-entraining and water-retaining admixtures. These show that 1:3 cement:sand and equivalent mixes containing lime all have very similar water-retaining characteristics, but are all much less water-retaining than a 1:3 lime:sand mix. These results therefore demonstrate the strong water-retaining characteristics of lime. (C) 1999 Elsevier Science Ltd. All rights reserved.