Look around your home. Are there cracks in the ceiling? How many times have you had shingles replaced on your house? Then consider this: Rome's Pantheon, Trajan's Markets and the Colosseum have been standing for nearly 2,000 years.
The Romans knew how to make cement.
Better than we do.
The endurance of Roman concrete has been checked with X-rays at the Advanced Light Source (ALS) of the DOE's Lawrence Berkeley National Laboratory, according to Phys.org.
"The mortar resists microcracking through in situ crystallization of platy strätlingite, a durable calcium-alumino-silicate mineral that reinforces interfacial zones and the cementitious matrix," said Marie Jackson, a faculty scientist with the University of California (UC) Berkeley's Department of Civil and Environmental Engineering, according to Phys.org. "The dense intergrowths of the platy crystals obstruct crack propagation and preserve cohesion at the micron scale, which in turn enables the concrete to maintain its chemical resilience and structural integrity in a seismically active environment at the millennial scale."
Most modern concrete is held together by limestone-based Portland cement. The limestone and clay are mixed and heated to 2,642 degrees Fahrenheit, releasing 7 percent of total annual carbon emissions. Roman architectural mortar is composed of 85 percent volcanic ash, water and lime and heated at a lower temperature, thereby reducing carbon.
The Imperial Romans made better, environmentally friendly cement.
Better than we do... right now.
"If we can find ways to incorporate a substantial volumetric component of volcanic rock in the production of specialty concretes, we could greatly reduce the carbon emissions associated with their production also improve their durability and mechanical resistance over time," Jackson told Phys.org.
What does this mean for the future? According to Jackson, "find ways to activate aggregates, as slag or as volcanic ash for example, in innovative concretes so that these can develop strätlingite reinforcements in interfacial zones like the Roman architectural mortars."