Yes, it is possible to mix concrete by hand using construction ballast. Concrete is made by mixing together cement, water, and a fine aggregate (such as sand) with a coarse aggregate (such as ballast). To mix concrete by hand, you will need to follow these steps: Combine the dry ingredients: Mix together the cement, sand, and ballast in a large mixing container.Add water: Slowly add water to the dry mixture, stirring constantly to ensure the ingredients are well-combined. The amount of water you need will depend on the specific mix ratio being used and the desired consistency of the finished concrete.Mix the concrete: Continue mixing the concrete until it is smooth and uniform in consistency.Pour the concrete: Once the concrete is mixed, it can be poured into the desired form or mould. Keep in mind that hand-mixing concrete can be labour-intensive and may not produce as consistent a mix as using a mechanical mixer. It is generally best to use a mechanical mixer for larger projects or for projects that require precise control over the mix.