What Concrete Mix Should I Use for Stepping Stones?

Making your own stone stepping stones is an easy and rewarding do-it-yourself project. They can be formed in any size or shape you want, or personalized to make the family mementos. A variety of stepping stone kits are available, containing all the forms and materials you need, but it's also possible to build your own forms and create truly unique stepping stones for your landscape. 

Other than your labor and ingenuity, concrete is probably the most vital ingredient in your stepping stones. But what kind of concrete should you use to make your stepping stones?

Terminology

The words cement and concrete are often used interchangeably—and incorrectly. The material used for the rock-hard surfaces that form sidewalks, driveways, and entry steps is known as concrete. One of the prime components of that concrete is cement—which is a fine gray powder made from pulverized calcined limestone and clay. It is this powdered cement that gives the bonding power and strength to poured concrete after it dries. 

Powdered cement is added to other ingredients in order to form concrete. The basics are cement powder, mineral aggregates of different types, and water. The variable here is in the mineral aggregate. This can vary greatly, depending on what the product will be used for. The main categories of cement are: 

• Mortar is a mixture that uses very fine sand with powdered concrete and water. It forms a very smooth-textured bonding concrete that is used for things like joining bricks or as the bed in which to lay ceramic tiles.
• Sand-mix concrete uses coarser sands, similar to playground sand, to form an all-purpose concrete. It can be used for sidewalks and paving surfaces, though is more likely to be used where a finer texture and smoother surface is required. 
• Gravel-mix concrete uses a mixture of small stones, or gravels, to form the concrete. This is another general-purpose concrete normally used for things like pouring driveways, retaining walls, or street surfaces. 

In addition to these general categories, manufacturers offer a variety of different formulations for specific purposes. These might include: 

• Quick-Setting Concrete: This is available at hardware or home improvement stores. These mixtures include special hardening agents that speed up the rate at which the concrete hardens. They are usually used in applications where low temperatures can otherwise make concrete take very long to harden, or in footings where you need strength quickly. 
• Crack-resistant concrete: This usually included polymers, vinyl additives, or bonding agents to give the concrete extra lateral strength. Concrete countertops and other surfaces where a durable, perfectly smooth surface is needed may use this formulation. 
• High-strength concrete: This mixture used aggregates of very hard minerals rather than more brittle sedimentary gravels. 
• Stepping Stone Concrete: You can find this concrete mixture at crafts stores. It is made especially for use in stepping stones and is quite expensive.

What's the Best Concrete for Stepping Stones?

Your choice of concrete will largely depend on the look you're after, as well as how many stones you are casting. Gravel-mix concretes will give you a pebbly surface that may be fine in some applications, but will make it hard to embed pieces of decorative glass or to make imprints. 

A good general-purpose sand-mix concrete is probably the best choice. An 80-pound bag should be enough to cast 5 to 6 stones, depending on their size. The texture is fine enough to allow you to embed decorative glass or pebbles, and it can easily accept imprints. 

Gravel-mix concrete is a good choice where you want a rough, pebbly surface to your stepping stones. It is an inexpensive material to use for stepping stones. But it is not the best choice if you plan to make imprints or embed glass or decorative pebbles. 

So-called "Stepping Stone Concrete" is probably not worth the high price, and there is really no reason to opt for any special concrete formulas, such as crack-resistant or high-strength formulas when casting stepping stones. It is the effort you put in, not the cost of the concrete, that will make your stepping stones special.