The asteroid belt is nothing but tourist traps, and the rest stops really thin out after Saturn. Some of you will want to consider flying. Luckily, at a Boeing 777's maximum velocity of 590 miles per hour, the trip to Pluto will take only about 680 years.
Yet structures like the Pantheon and the Colosseum have survived for centuries, often with little to no maintenance. Geologists, archaeologists and engineers are studying the properties of ancient Roman concrete to solve the mystery of its longevity. âRoman concrete is . . . considerably weaker than modern concretes. Itâs approximately ten times weaker,â says Renato Perucchio, a mechanical engineer at the University of Rochester in New York.
Definition of concrete. 1  1 : a mass formed by concretion or coalescence of separate particles of matter in one body. 2  2 : a hard strong building material made by mixing a cementing material (as portland cement) and a mineral aggregate (as sand and gravel) with sufficient water to cause the cement to set and bind the entire mass. 3 : a waxy essence of flowers prepared by extraction and evaporation and used in perfumery.