A. Limestone is abundant in Wisconsin, and it?s the material of choice for the surface of gravel roads, and the base for roads paved with asphalt or concrete. Limestone contains calcium carbonate, often with a mixture of magnesium carbonate. When chunks of limestone abrade against each other, small particles called “fines” are created, said Craig Benson, chair of the departments of civil and environmental engineering and of geological engineering at UW-Madison.
Office of Strategic Communication