There are examples of Roman Brickwork over most of Western Europe, not least in Italy. They have survived 2000 odd years and in many cases are still intact despite appalling weather and significant climate change.
I think particularly of the Roman walls in London which I’ve seen and can comment on. They were relatively thin bricks in deep beds of mortar. It was quite starting to walk down the road and suddenly come face to face with a wall in the open air that has been around for 2000 years in British weather.
The question is why does Roman Brickwork survive virtually intact while most modern brick work crumbles either in the brick itself or in the mortar?
In particular why don’t we have the same standards today?
Part of the answer is that materials were not so well understood, so there was a tendency to over-engineer. Same sort of thing with some examples of Victorian era metal, stone and brickwork. If you don’t know how strong something needs to be, you make it too strong.
There’s also some selection at work. By definition, you’re not seeing the examples that were not strong enough to last.
Roman bricks were hand made and they had the correct proportions of Silica, Alumina (clay), Lime and Iron oxide to make hard durable bricks. They had also perfected the manufacture of waterproof cement. This process was lost until the discovery of Portland cement in England in the mid 19th century.
Roman building materials are generally weaker than their modern counterpart. However, they also tended to use volcanic ash in their construction materials, and this is what gives those walls their amazing ability to withstand the elements (at least according to the Smithsonian). The particular chemical composition of their concrete and mortar happens to survive very well in weather, and once you get into the chemical analysis of it, the reasons for it are only partially understood. They arrived at their mixture formulas kinda by hit and miss and without as good of a knowledge of modern material science as we have, but they happened to hit on some very good formulas. Once they knew what worked and worked well, they kept with it.
The Romans also had this idea that they were conquering the world, so many of their structures were built to show off their superiority in construction. We, on the other hand, have more of a Walmart mentality with things. It doesn’t have to be as good, just make it cheap. When your primary focus is on the budget and the bottom line, you don’t tend to build quite so impressive structures.
And, as Mangetout pointed out, the things that weren’t built so well have already crumbled into dust. You are comparing their longest-lasting stuff with our average stuff, which isn’t a fair comparison.
I thought Roman remains in Britain tended to have spent significant portions of those (roughly) 2000 years underground or at least out of the British weather.
There are plenty walls, and Roman bricks reused for early mediaeval churches, and remnants of Roman structures such as lighthouses — however a deficit, especially of city walls, mediaeval or earlier, is more due to Georgian and Victorian improvers pulling them down for modernization ( and earlier regimes slighting them as punishment ); and 20th century developer slime putting up contemporary crap, than to failure.
Over-engineering Rocks.
Here’s a brick layer in the wall of the roman garrison of Eburacum
not half a mile from where I’m sitting now. This layer has probably been exposed to the elements for hundreds of years, and maybe enclosed in a medieval structure for a similar length of time.
