Different areas use different kinds of road surfacing for different purposes and types of traffic. High traffic areas need a different surface than lower use, e.g. country roads, rural areas, cheapo counties. Freeways, bridges, toll roads are often of cement because of the rate of traffic, or water involvement - it doesn't erode as quickly.
What we used to call macadam - is pretty old, maybe even the oldest of the road surfaces. Macadam was essentially laying of tar over dirt. It wasn't much more useful than defining a roadway. But it was fine for horses and carts. Cars pretty much did it in, since they moved faster and would often rip chunks or strips of it up on a hot day. Rains would erode it fairly quickly.
Tarmac was an extension of these types of roads where an actual road "bed" was laid, usually crushed stone, then the tar poured over it. Easy to fix: wait for a hot day, front loader scooped the road over where it belonged, or more tarmac dumped in a hole, rolled over and done. Different types of aggregate stone was used, depending on what was locally available. Gradually less tar and more, different types of elements added to it kept it more stable.
This was the predominate road surface until cars got moving over 45 MPH and tore it all up. But you still see a lot of it - I can remember riding on hot days and leaving hoof prints in the road, or getting sticks and rolling road pitch on them, then making little animals out of it.
Asphalt roads had more petroleum in them and were less temperature sensitive. It was also a cheap by product of crude petroleum. The big deal with that was, it could be mixed with the rock aggregate and laid - like one mixes cement with stones - rather than the stones laid in a bed, and tar poured over it. The difference was basically that it formed a better (for cars) surface, smoother, less give, less likely to be pulled up off the dirt, or eroded from below. It is a harder, more durable surface, more slick, and less likely to melt either in the sun, or from the heat of bazillions of tyres incessantly running over it. It pretty much stays where you put it, doesn't erode much, unless the dirt under it was badly laid, not smooth, or lots of water gets under it, in which case the DIRT erodes and the asphalt road collapses into the erosion bowl underneath.
Chip seal, bless its heart, is the cheapo version of road surfacing - like that nylon harness on eBay. Money strapped counties love chipseal. It started out as bed liner for asphalt roads to keep that pesty erosion at bay. Chipseal is built in layers, as opposed to rock with tar poured over of tarmac, or mixed rock and "glue" of asphalt. So you get a skimpy layer of asphalt over an already laid road, then a layer of small to fine crushed rock or aggregate (chips), which is then rolled over the asphalt layer, then finally sealed with something waterproof or ??? Lately, Yavapai county has been adding a mix of recycled rubber to the mix. This allows for more cushioning for tyres, resulting in less tyre tear-up as cars go faster than the posted 35MPH, and therefore less repair. Chipseal can be repaired by dumping more chipseal layers on it, rather than having to rip up all the cement or asphalt and relaying it.
Cement is just that. It's hard, slick, retains oil, so in a rain the oil lifts and creates an even slicker surface. It's more water resistant, so is often used on freeways with grooves for water to run through, so cars don't slide - hydroplane!
So those are the basics:
Tar will pull shoes on a hot day but basically as good for driving as dirt. Bad for doggie paws: burns pads on hot days, freezes pads in icy weather - think sticking tongue on frozen pole.
Tarmac better than tar, worse than dirt, can be slick, depending on how its laid. Has more spring, i.e. less concussion on feet. I work on it at a good trot with no issues. European roads generally tarmac since speed limits are lower and weather not as hot.
Asphalt is sturdier/harder, doesn't tend to melt, can be slicker and is generally laid for faster traffic, so watch for faster cars. Great for working up and down hills, walking or slow jogs. Doesn't generate as much heat on a hot day as does tar and tarmac, so slightly cooler to work on. Not my fave but inevitable.
Chipseal pretty much can work at any speed of trot. I don't ever canter on any road surface - too much concussion, too slick, bad news in a spook. If the chipseal is new, check for chips in the hooves. My neighbour's horse had chips work themselves up to the coronary band, although I will say they had hoof problems to begin with with wall separations. Still, it can obviously happen and it's easier to use a hoofpick.
The best thing about chipseal is the things they can mix in it - or the worst. Our county is mixing rubber. The surface tends to have a texture, sharpish at first, then grading down as traffic runs across it, but always some sort of texture. Good for keeping hooves trimmed (better if you have a rasp and keep on them). The rubber helps cushion the shock value. It makes for good conditioning for the horses.
Cement, just leave that alone. If it's down, there is a reason: fast traffic, fast water, low lying road with flash flood crossing it. No more than a walk, just too hard. Very slippery. We have a cement bridge by my house, I walk across it just to get horses used to hollow footsteps sound. I hate it because there is no place to go if someone yahoos across it. If the horses spook, all their feet go different directions. Happily most of us here have horses and even the motor cycles will shut their engines if needed. But cement better left alone.
So Leia, there are road surface basics from a rider/driver point of view!
Sorry for long
Okay, what the heck is the difference between "cement," "asphalt," "tarmac," "chip seal" and all the rest?!
I was using the terms interchangeably to mean "the hard stuff they pave roads in" but have no idea which is which.
Leia
