By: Meghan Thoreau, OSU Extension Educator, Community Development & STEM, Pickaway County
The Science of Concrete
Concrete is a composite material made from a mixture of cement, water, aggregates (such as sand or gravel), and admixtures (chemical additives). When cement comes into contact with water, it undergoes a chemical reaction called hydration, which forms a hardened paste that binds the aggregates together.
The Concrete Mixing Process
The process of mixing concrete involves combining the ingredients in the correct proportions and mixing them until a uniform consistency is achieved. The mixing process can be done manually or using a machine.
Making Concrete Stepping Stones
To make concrete stepping stones, you will need:
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Concrete mix
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Water
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A mold to shape the stepping stone
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A release agent to prevent the concrete from sticking to the mold
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Optional: decorative aggregates, such as small rocks or shells, to add texture and visual interest
Basic process for making concrete stepping stones:
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Prepare the mold: Before pouring in the concrete mixture, make sure the mold is clean and dry. Apply a release agent to prevent the concrete from sticking to the mold.
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Mix the concrete: Follow the instructions on the concrete mix package to combine the correct proportions of mix and water. Mix until a uniform consistency is achieved.
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Add decorative aggregates (optional): If desired, add small rocks, shells, or other decorative aggregates to the concrete mixture for added texture and visual interest.
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Pour the concrete mixture into the mold: Pour the mixed concrete into the prepared mold, making sure to fill it to the top.
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Vibrate the mold (optional): If you have a vibrating tool, such as a vibrating plate or a tamping tool, use it to vibrate the mold and eliminate any air bubbles in the concrete. If not, tap side of mold with firm finger tips for two to three minutes.
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Allow the concrete to set: Let the concrete set and harden in the mold. This can take anywhere from a few hours to overnight, depending on the temperature and humidity.
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Remove the stepping stone from the mold: Once the concrete has hardened, remove the stepping stone from the mold. If necessary, use a release agent to help release the stone from the mold.
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Seal the stepping stone (optional): To protect the stepping stone from the elements and extend its lifespan, apply a concrete sealer according to the manufacturer’s instructions.
- Seal the stepping stone (optional): To protect the stepping stone from the elements and extend its lifespan, apply a concrete sealer according to the manufacturer’s instructions.
