The alkali activation of metakaolin (MK) leads to the production of high-mechanical-performance network-structure materials. Adding calcium hydroxide (Ca(OH)(2)) to the raw MK produces a somewhat different reaction: a network structure and C-S-H gel form. In the present study, MK and (MK + Ca(OH)(2)) mixes were activated with 5M and 12M NaOH solutions and cured at 45degreesC. A 5M concentration, in the absence of Ca(OH)(27), did not produce MK activation within the test time. An activator concentration of 12M resulted in complete activation and the formation of a network structure. When Ca(OH)(2) was present in the raw mix, a small amount of C-S-H gel formed.