**7.1 Maximum compaction test**

With due attention to part 3 and the principle of additive chemical act, further use of RRP235special causes more water release using ion exchange process and decreases optimum water content. The more use of RRP235special, the more release of interlayer

**Figure 11.** *STPT test devices.*

**Figure 12.** *Maximum dry density curves.*

water. Also, the additive arranges the colloid placement. Releasing interlayer water and colloids arrangement increases congestion and maximum dry density. The results in **Figure 12** reveal that maximum dry density increases and optimum water content decrease by 4, and 38 percent, respectively.
