# Concrete pavement over a culvert **URL:** \ **Category:** General Discussion\ **Created:** [December 17, 2020, 3:56am UTC](https://community.cartalk.com/t/concrete-pavement-over-a-culvert/173374 "2020-12-17T03:56:01Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![RandomTroll](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/randomtroll/32/12184_2.png) [@RandomTroll](https://community.cartalk.com/u/RandomTroll)\ **Post date:** [December 17, 2020, 3:56am UTC](https://community.cartalk.com/t/concrete-pavement-over-a-culvert/173374/1 "2020-12-17T03:56:01Z")
I walked along a drainage channel this afternoon, crossed Chavez, a busy street, noticed that 15 feet of Chavez’s pavement over the center of the drainage channel is concrete; it’s asphalt elsewhere. The channel is much wider and there’s no support in the middle. Why was this bit concrete? This portion of the drainage channel is dirt. ---
**Author:** ![Purebred](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/purebred/32/46796_2.png) [@Purebred](https://community.cartalk.com/u/Purebred)\ **Post date:** [December 17, 2020, 9:48am UTC](https://community.cartalk.com/t/concrete-pavement-over-a-culvert/173374/2 "2020-12-17T09:48:18Z")
Not really able to picture what you are describing. Could you upload a photo? Concrete poured over culverts is self supporting, whereas, to my knowledge, asphalt is not. ---
**Author:** ![Mustangman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/mustangman/32/44130_2.png) [@Mustangman](https://community.cartalk.com/u/Mustangman)\ **Post date:** [December 17, 2020, 1:41pm UTC](https://community.cartalk.com/t/concrete-pavement-over-a-culvert/173374/3 "2020-12-17T13:41:14Z")
Maybe… concrete culvert pipe laid down to let the road pass over, concrete poured over to supoort traffic. Asphalt is a flexible surface that must be supported by a solid foundation. That is why asphalt highways have a concrete base, not a gravel base. ---
**Author:** ![MikeInNH](https://avatars.discourse-cdn.com/v4/letter/m/a587f6/32.png) [@MikeInNH](https://community.cartalk.com/u/MikeInNH)\ **Post date:** [December 17, 2020, 2:37pm UTC](https://community.cartalk.com/t/concrete-pavement-over-a-culvert/173374/4 "2020-12-17T14:37:22Z")
> [@Mustangman](#): > > That is why asphalt highways have a concrete base, not a gravel base. In the south they do…not up here in the north. Ours is very compressed gravel base about 2-3 feet thick. ---
**Author:** ![Mustangman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/mustangman/32/44130_2.png) [@Mustangman](https://community.cartalk.com/u/Mustangman)\ **Post date:** [December 17, 2020, 2:52pm UTC](https://community.cartalk.com/t/concrete-pavement-over-a-culvert/173374/5 "2020-12-17T14:52:28Z")
> [@MikeInNH](#): > > Ours is very compressed gravel base about 2-3 feet thick Must be a solution to the freeze-thaw expansion. My Ohio highway experience is when any major highway gets re-paved, they are done in concrete with a gravel base. Once the surface of the concrete starts to spall, they lay down an asphalt cap. I lived near a recently re-paved highway for a few years done in concrete. It was NOISY as heck in the winter when the leaves were off the trees. We were less-than-patiently waiting for the asphalt cap to be added to reduce the noise. A number of years ago, a ring-road got built in the Phoenix area all in concrete. Concrete holds up better than asphalt in the desert heat. The noise was a huge issue with the locals so they sprayed a coating that looked like asphalt seal coat on the road to quiet things down. ---
**Author:** ![wentwest](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/wentwest/32/6073_2.png) [@wentwest](https://community.cartalk.com/u/wentwest)\ **Post date:** [December 17, 2020, 5:39pm UTC](https://community.cartalk.com/t/concrete-pavement-over-a-culvert/173374/6 "2020-12-17T17:39:56Z")
Maybe they bridged the gap over the creek with a reinforced concrete plate. The steel could be completely within the concrete slab. ---
**Author:** ![Nevada\_545](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/nevada_545/32/41232_2.png) [@Nevada\_545](https://community.cartalk.com/u/Nevada_545)\ **Post date:** [December 17, 2020, 6:11pm UTC](https://community.cartalk.com/t/concrete-pavement-over-a-culvert/173374/7 "2020-12-17T18:11:40Z")
> [@RandomTroll](#): > > Why was this bit concrete? Strength, concrete can be reinforced, rebar doesn’t work well in asphalt. ---
**Author:** ![RandomTroll](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/randomtroll/32/12184_2.png) [@RandomTroll](https://community.cartalk.com/u/RandomTroll)\ **Post date:** [December 18, 2020, 4:22am UTC](https://community.cartalk.com/t/concrete-pavement-over-a-culvert/173374/8 "2020-12-18T04:22:55Z")
> [@Purebred](#): > > Concrete poured over culverts is self supporting It takes at least 60 feet to traverse the culvert; the concrete bit is only 15. Nothing is under the concrete to hold it up. > [@Mustangman](#): > > concrete culvert pipe laid down to let the road pass over, concrete poured over to supoort traffic. There’s no pipe: it’s open unfinished dirt in this stretch. > [@wentwest](#): > > Maybe they bridged the gap over the creek with a reinforced concrete plate. The gap is 4 times wider; nothing holds up the concrete part. ---
**Author:** ![wentwest](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/wentwest/32/6073_2.png) [@wentwest](https://community.cartalk.com/u/wentwest)\ **Post date:** [December 18, 2020, 4:24am UTC](https://community.cartalk.com/t/concrete-pavement-over-a-culvert/173374/9 "2020-12-18T04:24:51Z")
> [@RandomTroll](#): > > The gap is 4 times wider; nothing holds up the concrete part. Wanna bet? The law of gravity is final. If nothing is holding it up, it would not be up. ---
**Author:** ![RandomTroll](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/randomtroll/32/12184_2.png) [@RandomTroll](https://community.cartalk.com/u/RandomTroll)\ **Post date:** [December 18, 2020, 4:26am UTC](https://community.cartalk.com/t/concrete-pavement-over-a-culvert/173374/10 "2020-12-18T04:26:46Z")
> [@wentwest](#): > > If nothing is holding it up, it would not be up. There’s no extra support under the concrete part. ---
**Author:** ![Barkydog](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/barkydog/32/2470_2.png) [@Barkydog](https://community.cartalk.com/u/Barkydog)\ **Post date:** [December 18, 2020, 5:48am UTC](https://community.cartalk.com/t/concrete-pavement-over-a-culvert/173374/11 "2020-12-18T05:48:32Z")
In the village adjacent to us concrete drive aprons are prohibited due to plow damage. A corrugated metal pipe is typically used under asphalt.