Texture blending

Okay so I've been looking around trying to find an answer but i can't seem to find anything.

Basically what im trying to accomplish is to have an object with multiple texture layers, ill call them texture1 and texture2. my goal is to have texture2 on top of texture1 and over time or based off of a value i want texture1 to start showing through texture2, like alpha blending i guess? Any help or pointers would be greatly appreciated