If you want to mix concrete yourself in small batches or you are unable to find a company that will do it for you, you can rent an electric-powered concrete mixer.
Transporting the sand, gravel, and bagged cement requires a pickup truck with a bed that seals tight.
To mix your own concrete for footings and piers, use 1 part Portland cement, 2 parts clean river sand, and 3 parts gravel (maximum of 1 inch diameter and specially washed for concrete mixing). Add clean water, a little at a time, as you mix.
The concrete should be plastic, not runny. You can also use dry mix or transit mix, which contain the same proportions of cement, sand, and gravel detailed above. Tumble, adding water slowly for two to three minutes, and then pour. Concrete hardens because the powder-like cement and water form an adhesive that binds the sand and gravel together.
Too much water thins or dilutes this adhesive paste and weakens its cementing qualities; too little makes it stiff and unworkable. If the batch is too stiff, add water one cup at a time and continue mixing until it’s right. If it is too soupy, add small amounts of sand and gravel. Keep in mind that concrete changes consistency radically when you add even small amounts of any ingredient.