Dear James: I need to do some projects around my house that require patching and adding some concrete. Is this a project the average do-it-yourselfer can do without expensive tools? —Sharon M. Dear Sharon: If you have a container or wheelbarrow for mixing the concrete, and you are strong enough to carry the heavy bag of dry concrete, you should be able to do simple concrete projects yourself. The key to a good result is carefully chipping out all the deteriorated old concrete for a stable base. Before starting your project, it is wise to understand how concrete works so you can use it properly. The mixture percentages and timing are important. Contrary to popular belief, concrete does not dry when it is poured. Instead, it cures through a chemical reaction among its components. Concrete is just a dry mixture of cement and some type of aggregate, usually sand and …