*3.3. Water Absorptivity of Cement Paste Samples*

The results of water absorptivity values obtained for the respective cement paste samples have been presented in Figure 5. Considering the results, it might be stated that the water absorptivity of 0.30 5% is similar to 0.30 ref. However, as 10% and more of cement is substituted with spent catalyst, the water absorptivity increases. The values obtained for 0.30 10%, 0.30 15% and 0.30 20% are also similar to each other, nonetheless, exceeding 0.30 ref for 17%, 14% and 17%, respectively.

**Figure 5.** Effects of cement substitution with spent FCC catalyst on the water absorptivity of cement paste samples.
