Old concrete was better - Down the Road

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Old concrete was better

31 July 2026

Jim Grey

14 comments on Old concrete was better

3–4 minutes

concrete, highways, National Road, Putnam County Indiana, roads, US 40

Not long ago I revisited some favorite places on the National Road in Putnam County, Indiana. One of them was this short stretch of concrete road east of Reelsville. This photo is eastbound, from the intersection with CR 800 W.

Notice how the concrete appears to curve off to the right, and the road beyond is gravel. It’s a long story that I told here, but the concrete was removed past that curve and no road exists there anymore.

Here’s the westbound road toward its dead end just ahead of modern US 40. This is private property now and serves as a driveway.

Notice that there are no expansion joints in this road. I’ve seen a few other examples of what I call "continuous concrete" around Indiana, including another segment of former US 40 not too far away, a segment of former US 52 in Indianapolis, and a since-demolished segment of State Road 37 near Martinsville.

My hypothesis is that Indiana built continuous concrete roads before figuring out that expansion joints reduced cracking and therefore maintenance. Based on my research, I’ve not seen any continuous concrete roads that were built after about 1925.

I’ve always marveled at the good condition these centenarian highways are in. Many of them were bypassed within ten to 20 years, this section of US 40 among them. The pattern for well-traveled highways was that Indiana first hard-surfaced them in place during the 1920s, and then starting in the 1930s built bigger, better new alignments nearby.

I assumed that part of these concrete highways’ good condition was that they served as highways for only a short time, and the local traffic that used them thereafter weren’t enough to wear the road down, even after a hundred years.

Not long ago, reader Phil (Kamera Ostalgie) left a comment about old concrete highways that added to my knowledge. I’m sharing it here because it’s so useful.

The older concrete roads lasted such a long time because concrete was produced differently and ordered differently back then. You used a ratio system. So lets take a common mix like 1:2:4 which was a standard structural concrete and was made up of 1 part cement, 2 parts sand, and 4 parts aggregate. You the customer ordered the ready mix concrete at the ration you required. So the key is here the customer had control over the actual cement content.

In modern times you ordered your ready mixed concrete by the strength you needed in Newtons. So if you ordered a 21 Newton concrete all the concrete had to do was reach the specified strength of 21N/mm2 at 28 days.

This is crucial as the concrete manufacturer could and did, put in what weight of cement they wanted into the mix, as long as the concrete reached 21N/mm2 at 28 days old when cube tested. This was free reign for the producers to take out expensive cement.

This meant that manufacturers took out actual Portland cement which was very expensive and replaced some of the Portland cement with materials like finely ground blast furnace waste. Also additives in the form of industrial soaps were added to improve density and reduce the water content which in turn increased 28 day strengths. So ready mix producers tried anything and everything to reduce actual expensive Portland cement contents in their mixes.

But whilst they produced concrete to the specified strength the customer ordered, durability was reduced as the Portland cement content dropped.

So to sum up, the old highway concrete would have had far more actual Portland cement in it than modern equivalent concretes. This is the main reason for it durability, there are others of course but this comment would end up like a book if we went into them.

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14 responses to "Old concrete was better"

Peter Miller

31 July 2026

This was very illuminating. A gentlemen I knew had a second career selling ground-up tires mixed into concrete. My neighbor sold me on getting our driveway power washed by his daughter’s boyfriend. He did a great job. My neighbor commented on the quality of our 65 year old driveway with "good" concrete. It has cracks and needs to be leveled but does look pretty good.

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Jim Grey

31 July 2026

Ground-up tires? Wow, I didn’t know that was a thing.

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Martin

31 July 2026

Recycling old tires in Asphaltic Concrete (the technical name for "asphalt"), not Portland cement concrete, is indeed a thing. How much used and how successfully is another matter.

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Jeff Sun

31 July 2026

Well, I have always figured that concrete could be strong enough to last as...