why concrete roads are always laid in blocks & gaps between the blocks are filled with tar?
819539
expansion joints- so when the road freezes or gets hot- expands or shrinks- the road can heave and move without cracking and breaking the road itself
375789
A concrete velodrome is no different from any other concrete structure.  The design will first specify a design of the base including information on soil compaction.  The concrete design itself will have steel rebar.  In some construction, a fiberglass filler is added in addition to or as a replacement to the rebar.  Concrete is extremely strong in compression, but very weak in tension.  Alternatively, a design could be made using pre-stressed concrete.  This method uses steel cables and plates to place the concrete under significant compressive stress.  This prevents the deflective load from placing the concrete under tension.  Tension stress is what ultimately causes the cracks.
432384
There are two typical means. The first (and oldest) is poured on site over a "rebar" type super structure. The second is made from "precast" sections that are delivered  and installed at the job site.
927570
"Excavating the road box" is pretty much what it means.  It means cutting into the original ground to create a "box" in which the structural section will be placed (think of a long sandbox).  In fill areas, the soil from the cut section will be placed and compacted or imported borrow will be used if there is no material available on site.  In the fill sections, the depth of the fill would only need to enough to match the elevation of the cut section.\n\nThe structural section is then placed on top of the original ground in the "box".  The structural section usually consists of a subbase, a layer or two of base material and then the surface of the roadway which typically would be concrete or asphalt concrete.
22240
My understanding is that it comes from cement trucks.  Cement trucks (apparently) carry nine yards of ready-mix concrete.  When they have emtied their entire load, they have dropped "the whole nine yards".  I've also heard that it comes from sailing (as do tons of sayings like that), but the cement-truck explanation seems pretty plausible to me.
412071
there are 1 or 2 tracks that are concrete and a few have concrete turns. concrete can be hard on your tires. asphalt is easier to maintain.. thanks for asking...
1072725
Concrete has limestone,calcium crystals etc,so even if you heat it at high temp or low or leach it ,transparency won't happen.\n  But, optimally cooled resin is transparent and can be used to set biological preserves , infrastructural support etc, but cant be used for large structures.The acid test lies in at which rate you cool it.
662022
No, most of it is chemically incorporated into the crystalline structure the cement forms.  Of course, some does evaporate, but this is undesirable.  This is why concrete is often covered until it cures.
644959
Um maybe you should talk to someone else about this. Check your city hall or something. I havent even heard of smackover, Arkansas! Anyways, blocking a RIGHT of way needs to be addressed if you or someone else is blocking it. There could be flammable gas underneath your feet! Be careful! If you can't contact someone, call the company who owns the line in the right of way and ask them if they can forward you somewhere.
1112775
The density of dry loose gravel regardless of size is on average about 90 to 105 pounds per cubic foot. This assumes a fairly consistent size. If the gravel is a mixture of large and very fine material then it will be some what higher because the fine grains will fill in between the larger pieces. \n\nAny granular material that is evenly graded (all pieces about the same size) will have the same degree of void space between granules. It calculates to around 30% (I don't remember the exact number but you can calculate it you like). Most sand and gravel is made of the same ground up rock, therefore density of the individual grains or pieces is the same. With 30% of any cubic foot the same and the density of the grains the same, sand or gravel will have the same density.
656252
It is because the round or circular shape is the most uniform shape of all (there are no edges or corners) - this means the amount of stress force exerted from the surrounding soil is uniformly distributed onto it; wheareas if it was some other shape with corners or edges, then stress concentration would be higher at those places, which would cause cracks/erosion that can destroy the pothole.
20791
Most potholes are caused when water seeps into the pavement surface and eventually freezes, creating pressure as it expands. This weakens the pavement surface and as vehicles pass over, it breaks the area into smaller pieces. \n\nEventually the pieces vacate the cavity and a pothole is created. If a pothole isn't fixed in a timely manner, and additional water invades it, erosion will be accelerated and the pothole will become more pronounced.
228898
I had the same thing keep happening to me, so I took a big,long, steel pipe and dug down about 3 feet deep and concreted it in the hole. Then I covered the concrete with dirt,built a square tube out of 1x4 boards and placed over the pipe. Then nail the mailbox to the boards, now your mail box looks like any other mailbox! Let someone run over this mailbox and they can say good bye to their car!lol
623326
Because they always spend the money on roads that don't really need repaving and cause traffic jams and accidents.  I was in an accident due to a crappy job of road workers giving ample warning that traffic on an interstate was about to come to a halt at the bottom of the hill.
754059
The concrete at Bristol is coming apart? Well, that's news to me. Been to Bristol a few times and don't miss a race, never heard of any trouble with the concrete coming apart ever.
849362
It's way too funny.... Since you put it into perspective, I'm wondering why, since we technically pay for the roads, why are the roads around here full of potholes??? If I'm paying for them, I think they should be repaired as needed.......
258149
Sell them to a company that shreds them and mixes them with concrete to make highways.  It's good for the environment.