Next: Degree of Hydration
Portland cement meeting the requirements of ASTM Type I was used for all specimens .
The sand chosen for the mortar specimens was ASTM C109 Ottawa sand. All samples were
tested at room temperature (25ºC). Two water/cement (w/c) ratios of 0.40 and 0.50 by mass were
chosen for all cement paste and mortar mixes. The sand volume fraction (percentage of total mix
volume) was 0, 35, 45, or 55 %. Entrapped air contents were allowed to vary (1 to 1.2% for
pastes and 7 to 9% for mortars). Vacuum consolidation was not used in order to simulate field
conditions for the mixing and placement of mortar and concrete. The mixtures were cast into 100
x 200 mm cylinders and rotated for the first 20 to 24 hours to minimize segregation and bleeding.
Following rotation, the samples were demolded and either stored in saturated lime water or
prepared for testing, depending on the degree of hydration required.