Another Florida Post - Asphalt Mix

[Fred Defender]

This is another oddball sort of question (the kind that you'd expect from me). Those of you that lived/grew up in Florida like me - and are old like me - will remember this:

Back in the 1950's/60's and up until the early-70's, Florida paved its state highways with an asphalt mix that was more white than black. I remember noticing as a youngster, riding my bicycle on one of these road surfaces, that the asphalt had pieces of seashell in it. By the late-70's, the state had gone to a gravel mixture that was decidedly blacker and much more prone to crumbling. If you lived on the West Coast south of Tampa, you may recall the newly-constructed I-75 pavement prematurely failing when the surface pretty much disintegrated after only five years or so. In Alachua County, County Road 235A (formerly State Road S235A) in the City of Alachua was repaved with this same mixture. Alachua County roads are known for being pretty crappily-maintained and much of the original whitish asphalt on 235A can be seen underneath the long since crumbled gravel mixture.

But, to my question...why did Florida get away from the lighter-colored mixture? I would think that the lighter the color, the cooler the road surface would be. I would think that a cooler surface would be less prone to softening and crumbling. It seems like the darker mixes require resurfacing at least every ten years. But, as I recall, many of those early lighter pavements (where I grew up...US41 between Sarasota/Bradenton and Venice, for instance) lasted at least fifteen years before they required resurfacing.

[realjd]

The answer is almost certainly cost. The whitish stuff was probably more expensive.

Another good example is the widening of I-95 through Brevard County. 8 years ago when they widened it, oil (and thus asphalt) was super expensive so they used concrete for the first part north of SR519 (Fiske). Oil prices dropped and they switched back to asphalt for the rest of then construction.

[jwolfer]

This is another oddball sort of question (the kind that you'd expect from me). Those of you that lived/grew up in Florida like me - and are old like me - will remember this:

Back in the 1950's/60's and up until the early-70's, Florida paved its state highways with an asphalt mix that was more white than black. I remember noticing as a youngster, riding my bicycle on one of these road surfaces, that the asphalt had pieces of seashell in it. By the late-70's, the state had gone to a gravel mixture that was decidedly blacker and much more prone to crumbling. If you lived on the West Coast south of Tampa, you may recall the newly-constructed I-75 pavement prematurely failing when the surface pretty much disintegrated after only five years or so. In Alachua County, County Road 235A (formerly State Road S235A) in the City of Alachua was repaved with this same mixture. Alachua County roads are known for being pretty crappily-maintained and much of the original whitish asphalt on 235A can be seen underneath the long since crumbled gravel mixture.

But, to my question...why did Florida get away from the lighter-colored mixture? I would think that the lighter the color, the cooler the road surface would be. I would think that a cooler surface would be less prone to softening and crumbling. It seems like the darker mixes require resurfacing at least every ten years. But, as I recall, many of those early lighter pavements (where I grew up...US41 between Sarasota/Bradenton and Venice, for instance) lasted at least fifteen years before they required resurfacing.

Also the reason for the black counter stripes in Florida

[FLRoadsGuy]

The original concrete on I-75 in Manatee and Sarasota Counties failed as water was seeping the cracks and instead of doing a quick fix for this long stretch FDOT did a total rebuild in the early 1990s. I-275 in southern St. Pete was built the at the same time and with the same pavement type but wasn't as bad and made fixes to make the concrete strong.
With the whitish colored asphalt pavement my guess would have to be with the local white sandy soils.

SM-N920T

[Fred Defender]

The original concrete on I-75 in Manatee and Sarasota Counties failed as water was seeping the cracks and instead of doing a quick fix for this long stretch FDOT did a total rebuild in the early 1990s. I-275 in southern St. Pete was built the at the same time and with the same pavement type but wasn't as bad and made fixes to make the concrete strong.
With the whitish colored asphalt pavement my guess would have to be with the local white sandy soils.

SM-N920T

Good point regarding I-75 the concrete in Manatee/Sarasota. This was a colossal CHARLIE-FOXTROT. The concrete (they called it "econocrete") began cracking before the highway even opened. Within ten years, sections of it had pretty much crumbled into oblivion requiring a 30+ mile stretch to be completely rebuilt and paved with asphalt. The asphalt section that I referred to was immediately south of the concrete section - south or SR681 near Venice. That asphalt began disintegrating within a few years, also. I remember FDOT placing signs along that stretch prior to resurfacing, "Warning: Loose Gravel". Of course, Florida taxpayers took it up the whazoo for the entire shooting match.

Also good point by jwolfer regarding the black striping.

There are a number of county (formerly secondary-maintenance state) roads in rural northern Florida that still have the whitish asphalt mix. I traveled several in Union and Bradford Counties this weekend during a motorcycle ride.