Limestone aggregate is a natural resource. Like all natural resources, it can be depleted. Additionally, limestone can be expensive to mine, and transport – activities that also create a carbon footprint. In construction, limestone aggregate is used primarily as base material that compacts well and allows for a finished surface like asphalt and concrete to be laid on top.
Recycled concrete, stone, hard fill and similar demolition waste are more sustainable construction materials that are equally effective compared to limestone aggregate. In fact, lab testing has shown that commingled recycled aggregate has a similar characteristic to limestone aggregate of the same size range.
Recycled aggregates cost about 50% less than natural stone and yield the same if not better results.
The New Jersey EPA performed a pilot project using recycled aggregates and other natural stones as a base under permeable pavers and concluded that recycled aggregates was just as safe as the other aggregate options.