Aggregates have been around since before humans walked the earth, formed in the fires of volcanoes and moulded by erosion, time, water and glaciers. The first type of concrete, a mixture of gypsum and lime, was used in ancient Egypt during the building of the pyramids as a mortar between the stones. It was in Roman times that concrete really became a construction material of choice. They had a recipe that used volcanic ash, lime and salt water that produced an incredibly strong building material. Unfortunately, the curing time of the Roman concrete was significantly longer than today’s concrete. The Romans were excellent engineers and used rock and concrete in almost everything they built, from aqueducts and bridges to roads and buildings that are still standing today. In almost every country in the world you can find ancient structures that used some form of aggregate.