scoria bricks, a material they made roads with, in York England, that I've never heard of until now! They weren't a success because they were found to wear unevenly and become slippery in wet conditions

In the mid-19th century, Teesside ironmasters faced the challenge of disposing of molten slag waste from blast furnaces, and used an ingenious method invented by Joseph Woodward in 1869 to transform this waste into durable, silvery-blue bricks.

Producing one ton of iron produced one ton of slag. As the furnaces of Cleveland, Hartlepool and Consett were producing 2.5 million tons of pig iron a year towards the end of the 19th Century, there was an awful lot of slag turning up everywhere..

At first, it was tipped onto the boggy marshlands around Middlesbrough to raise them up. When these were filled, the ironmasters then ended up paying the Tees Conservancy Commissioners 4d a ton in old money to take the slag away. The Conservancy Commission used it to good purpose, with over 20 miles of riverside walls and the North and South Gares built up on slag, a base still there to this very day.

But not only was this product a waste – it was a waste of money as well . The ironmasters did not want to pay to have their rubbish removed. They wanted to profit from it, to really show that where’s muck, there’s money.

 At its peak the company was taking 30% of the slag from the South-Tees works.

  These bricks became popular for paving roads and alleyways due to their strength and resistance to water and frost.

The bricks were also exported around the world and can be found in Canada, West Indies, Netherlands, Belgium, United States, India and South America

Millions of tons of pig iron were being produced in Cleveland in the North East of England at the time, generating much slag waste, a real problem for the ironmasters, as it was expensive to remove.

Scoria bricks were a kind of basalt, an igneous rock, very hard to break, very durable, completely waterproof, frost-proof and indeed chemical-proof, Eventually however the motor car destroyed the business, when it replaced metal-rimmed carriages, as people wanted a smoother ride, and tarmac started to follow in the 1930s. Steel and iron making ran down and by 1966 the Company went bankrupt

 York has around 16 miles of back lanes, a third of which use scoria bricks.

In 1912, 62,881 tons of scoria bricks were exported from wharves along the Tees. Thirty-seven per cent of these went to Canada, and 36 per cent to the West Indies. Smaller quantities went to Holland (Rotterdam was an early customer), Belgium, the US, South America and Africa. There are lots of them in fact in Dublin and other Irish towns. As the average scoria brick weighs 13lbs, this means that in 1912 alone, nearly 11 million bricks were exported.

https://www.clementshallhistorygroup.org.uk/blog/the-story-of-the-scoria-brick-a-recycling-success/

https://en.wikipedia.org/wiki/Scoria_brick

https://northeastbylines.co.uk/region/north-east/scoria-bricks-history-at-our-feet/