Page 27 - RoadCem Manual - PCT BV

The strength of cement bound products is very much dependent upon the hydration reaction just discussed. Water plays a critical role, particularly the amount used. The strength of the product increases, when a lower amount of water is used. The hydration reaction itself consumes a specific amount of water.
CEMENT PARTICLES SUSPENDED IN MIX WATER
FULLY HYDRATED CEMENT
LOW WATER:CEMENT RATIO
HIGH WATER:CEMENT RATIO
LOW POROSITY = HIGH STRENGTH
HIGH POROSITY=LOW STRENGTH
(Yellow is water, blue is cement)
Figure 2.4 Schematic drawings to demonstrate the relationship between the water/cement ratio and porosity.
The empty space (porosity) is determined by the water to cement ratio. The relationship between the water to cement ratio and strength is shown in figure 2.5.
Figure 2.5 A plot of product strength as a function of the water to cement ratio.
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