How Roman bridges can be still standing after 2000 years, when your 10 year old concrete driveway is cracking? You can find your answers below, from the top-rated explanations on the internet.
Before you build a bridge you have to make sure the soil under it can bear the weight, the soil has to be very compact and stable. They had ways of doing this similar to a proctor test and a sand cone testThe ancient Romans being the best civil engineers that history would see for centuries learned it the hard way. This is before science so it was just an ongoing record of learning from past mistakes with knowledge handed down to the next generation. They only built with the best plans, with the best material available. Earthquakes are a big problem in Italy so you have to “over build” often. That means make something much stronger than necessary every step of the way so that when it’s finished it’s going to stick around.
They also made sure to pick the best spot for their bridges and would sometimes dig and dig and dig to make sure that if there is bed rock, they’ll hit it.
Also, you have to remember that after thousands of years all of the ones who couldn’t survive the test of time fell apart. What you’re seeing is the ones who could and did.
What you are seeing in your driveway is the cheapest cement on discount at Home depot, poured by the cheapest guys a crooked sub-contractor tricked into working in terrible conditions regardless of the untested soil.
Old stone bridges that are still standing probably had their footings build on solid rock or very stable earth. By contrast, your driveway was poured onto earth that moved or eroded under it.
Fortunately, cracked driveways are still safe to use, unlike cracked bridges.
A lot of Roman stuff still standing has been maintained and periodically fixed. The Colosseum for example has new parts that keep it from further damage. However, the Colosseum was actually built with iron supports originally to keep it from falling down. After the empire collapsed, people removed the iron to sell for scrap. It would be in a lot better shape now if people didn’t use it for parts.
The Colosseum has been quarried for a long time and most people stealing the stone did not care enough or appreciate disturbing the structural integrity of the building. Also, there have been major earthquakes in and around Rome since the Romans built it. So the government there has been forced to reinforce a lot of the Roman architecture. However, without the pillaging most of it would be intact even with earthquakes.
Volcanic ash causes reactions which produce additional calcium silicate hydrate which acts as a binder. It also increases the concrete’s resistance to chemical attacks. There’s a report called ROMACONS on its use in hydraulic concrete in ancient Mediterranean ports for anyone interested.