Quick Answer
Cinders can be used as a driveway sub-base material, but it's crucial to ensure proper compaction and drainage to prevent settling and water damage.
Compaction Requirements
Compacting cinders is essential to create a stable sub-base. Use a vibrating plate compactor or a heavy roller to achieve a minimum of 95% compaction. This can be achieved by applying 3-4 passes with a vibrating plate compactor or 2-3 passes with a heavy roller. It’s recommended to compact cinders in 3-4 inch layers, allowing for adequate moisture to be absorbed between each layer.
Drainage Considerations
Cinders can be prone to water accumulation and erosion, which can lead to settling and damage to the driveway. To mitigate this, incorporate a 1-2% slope into the driveway design to allow water to drain towards a designated area. Additionally, consider installing a French drain or a permeable paver system to further improve drainage.
Material Sourcing and Specifications
Ensure the cinders meet the specifications outlined in the American Association of State Highway and Transportation Officials (AASHTO) M 302 standard. This includes a maximum particle size of 3/4 inch and a minimum dry density of 85 pcf (pounds per cubic foot). It’s also essential to source cinders from a reputable supplier to ensure consistent quality and minimal contaminants.
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