Related Links: Recycling Asphalt Rescues Roads The rate of evolution in highway products is very slow compared to electronic, medical or communication products. If you think back to the 1960s, roads today still have the same asphalt, concrete and signs.In fact, we are still designing pavements based on the American Association of State Highwa and Transportation Officials' road tests of the early 1960s. On the other hand, if you compare cars, computers, household products and medical facilities to those of the 1960s, you see a much greater change.I have always felt amazement at nature's brilliant selection process that advances the
Arch dams, classically curved monoliths situated in narrow valleys, are not as common as other types of dams, such as embankment dams and gravity dams. ENR takes a look at some of the biggest arch dams in the world, both completed and under construction.