I want to extend my driveway (from the side) by about 3 1/2 feet. Roughly the size of a sidewalk, albeit a slightly oversized one. A friend of mine has offered to give me about a dozen bags of Dolomite Lime (I believe it's the type normally used for drywalling), which he says I can use to mix my own concrete for this project. Can this be used/would this work? What else would I mix with it to make a durable cement? Or should I just tell him to keep his kind offer?