The reason is that the bonds between particles are weakened as the particles are moved further apart and appear simultaneously disruptive internal pressures through the clay–cement system making this more susceptible to erosive forces (Paaswell, 1973; Yoder, 1967).
The internal force system of a cement stabilized clayey mixture is defined as the resultant stresses established by the bonding potential (A) (attractive forces) of cement and the swelling potential (R) (repulsive forces). The net force acting between particles is strongly dependent on the relative magnitude of the repulsive force (R) and the bonding potential (A) and can be illustrated for combinations of (R–A) as follows:
(R–A) < 0 net attraction (bonding potential of cement). The strength and durability of clay–cement system are increased,
(R–A) > 0 net repulsion. The swelling forces are higher than the cement bonding forces. The strength and durability of clay–cement system are reduced,
The A-forces are highly susceptible to changes in the amount of cement, compaction, curing and soaking time whereas the R-forces are dependable on the environmental changes regarding the amount of water intrusion.
Finally R and A forces are strongly related to the type and amount of clay participated in cement stabilized soils (Table 2). Conclusively the net resulting force of (R) and (A) forces influences the resistance against deformation ( applied external force – unconfined compressive strength) and durability (bonding effect).
In an effort to evaluate the engineering effect of stabilization parameters (curing and soaking time, compaction, amount of cement used) of kaolin and active bentonite and their connections with strength and durability both slaking and unconfined compressive strength tests were carried out.
Final objective of present research work was a study of final water content and its influence on strength and durability.