Ancient Roman seawalls that have been exposed to the elements for over 2,000 years are finally beginning to reveal the secret of their longevity to researchers trying to figure out what makes them so durable. Lasting for 2,000 years in impressive enough, but even more impressive is the fact that the concrete barriers have actually strengthened over that time period.
According to Time, new research published in American Mineralogist discovered it is a mixture of volcanic ash, lime, seawater, and a mineral called aluminum tobermorite that gives the concrete its durability.
This mixture can reinforce the wall and prevent cracks from expanding. The reaction was caused by seawater continually pounding the structures for centuries, which allowed the mineral mixture of silica oxides and lime to grow between the volcanic rock aggregate and mortar to develop resistance, Time reports. This Roman concrete thrives in open chemical exchange with seawater, which is very rare on Earth.
The information gleaned from this research could prove vital in developing a more environmentally friendly, longer-lasting concrete that could be used in projects today’s concrete would be deemed unsuitable for such as sea barriers or coastal structures.