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red750
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Hey, Phil and Jerry, how are you dealing with the heatwave? Saw a picture on the TV of a guy buried up to his ankle in a bitumen road that gave way in the heat. Needed emergency services to chisel him out. A recycling truck also sank up to its axle.

 

 

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If the bitumen was so soft that he sank into it, why did he need to be chiselled out?

 

I think you will find it was a faulty batch of bitumen. I saw on TV that people were replacing their tyres. Funny that tyres on the trucks used for roadworks get a fair bit of bitumen on them with no problems.

 

 

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You have to realise that the roads in the UK, Europe and North America have a lot more tar in the mix than we do. We can't have so much for the obvious reason - heat.

 

As for people replacing tyres that have got a covering if bitumen - I bet that there's an ill-informed social media post behind the idea that the tyres need to be replaced.

 

 

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Bitumen & Asphalt are apparently one and the same thing but I always considered bitumen to be hot tar spread by spraying & gravel then laid on top & rolled in. It is generally fairly noisy to drive on. Also called Tar Macadam or Tarmac. Asphalt I thought was normally premixed and laid hot by a machine & the surface can be very smooth. I think this is sometimes referred to as Asphalt concrete & does not seem to suffer from extreme heat. This is what they put on motorways near built up areas as it is quieter to drive on than concrete. Am I right here?

 

 

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Bitumen is the black gooey stuff. Asphalt (USA) or macadam (British) is a mixture of bitumen and solids (usually stone, but any hard material like glass or shredded rubber can be used). Since it is a mixture of a binder and material to be bound, it could be more accurate to call it asphaltic concrete.

 

The finished surface's resistance to heat damage depends on the percentage of bitumen in the mix

 

The desirable properties of Asphalt mixes are:

 

1. Resistance to permanent deformation: The mix should not distort or be displaced when subjected to traffic loads. The resistance to permanent deformation is more important at high temperatures.

 

2. Fatigue resistance: the mix should not crack when subjected to repeated loads over a period of time.

 

3. Resistance to low temperature cracking. This mix property is important in cold regions.

 

4. Durability: the mix should contain sufficient asphalt cement to ensure an adequate film thickness around the aggregate particles. The compacted mix should not have very high air voids, which accelerates the aging process.

 

5. Resistance to moisture-induced damage.

 

6. Skid resistance. (That's where using rubber granules comes in.)

 

7. Workability: the mix must be capable of being placed and compacted with reasonable effort.

 

8. Low noise and good drainage properties: If the mix is to be used for the surface (wearing) layer of the pavement structure.

 

 

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Lastly, as far as I know,

 

All tarred road surfaces are plastic.

 

The composition must allow the surface to be gently massaged by the vehicles. Otherwise it cracks and fails prematurely.

 

So the blend is carefully chosen to suit the "normal" ambient temperature. Different mix for different climates.

 

 

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Once water gets underneath it's going to deteriorate The neatest stuff is hot mix. Flexing knocks any surface around. It cracks and then refer para 1. The extent of stabilization of the base depends on the load carried...For aircraft Runways, taxyways and parking areas the Pavement Depth Factor relates to max tyre pressures as well, as total mass.. If you run a heavier plane on an area that's not up to carrying it you won't be popular. . Nev

 

 

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Road design is taught in a subject called Flexible Pavement Design. Even big freeways are designed to flex under load without cracking. If load is too great (say big trucks on rural roads) then cracking and water penetration follow.

 

 

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Interesting thread; perhaps someone who has contributed here knows a bit about the "earth glue" used to stabilise gravel roads.

 

Our council used our 200m access lane as a test strip and I'm impressed. Despite its steep slope and regular traffic, there's very little wear, and (before the drought) heavy rain caused no erosion. I'd like to try something similar - but hopefully less pricey- on my steep driveway.

 

 

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Asphalt is usually considered to be a mix of bitumen or asphalt with stone and mixed hot, transported to site and laid with a machine to get an even finish. It is then rolled before traffic goes on it.

 

Spray seal is the other method which uses a sprayed coating on the road base, either hot or cold and then one or two coats of stone, layed in fine layers, a quick rolling and it is ready for traffic and windscreen smashing.

 

I am not sure what was used in N Qld and failed, but my guess is it was a spray seal with stone layers and it just stuck to the vehicle tyres.

 

 

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Last night I was stopped at an intersection on Camden Valley Way near Camden. Millions of dollars have been spent widening this road to four lanes. The road serves major new residential and light industrial areas. There is a high volume of traffic, including a high percentage of heavy vehicles. I noticed that the road surface in the left hand lane has collapsed and the surface seal has furrowed. Obviously forethought was not one of the criteria for the design of the road.

 

 

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Building roads to cope wit 85 tonne vehicles braking and turning, is going to be costly always.. There used to be limited access to light duty roads . I feel that is a good idea. They can't get around a lot of roundabouts either. Cars with "switched off" drivers mixing it with the heavies is a recipe for disaster. too. Nev

 

 

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Hey, Phil and Jerry, how are you dealing with the heatwave? Saw a picture on the TV of a guy buried up to his ankle in a bitumen road that gave way in the heat. Needed emergency services to chisel him out. A recycling truck also sank up to its axle.

Thanks for asking, Red... Well, I am enjoying it, although air conditioning in buildings in the UK are not built to actually work... The sun is shining, the grass is brown - we are rethinking our move to Aus! Typical though - weather is perfect and I need a renewal and my examiner is holidaying somewhere - where it is raining I believe (well, not really, but it would make me feel better). Yes, I can get another examiner, but this guy puts me through my paces pretty stiffly while others may be a little more cheek turning.

 

Gents - I have to be honest - when the sun is shining, London IS one of the best places in the world to go window shopping.. I live in Barnes during the week - leafy suburb and the people are very well groomed and kempt.. They are definitely more petite than Aussie girls in general and aren't as weather beaten..

 

Bring it on!

 

Yours Sincerely,

 

Lecherous Bar Steward...

 

 

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Been in London in a heat wave. They don't even have water bubblers you can get a drink from. All you can do is buy a sticky sweet sugary ice cream which makes you even more thirsty. Aussie girls are the most variable in the world because they come from all over the world.. Like a Chinese restaurant menu A big choice. Nev

 

 

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Like a Chinese restaurant menu A big choice. Nev

Reminds me of the young Chinese restaurant-owning couple on their wedding night - they hadn't had much experience at sex and neither knew what to do.

 

Finally the girl shyly says... "Maybe you like to try a number 69?"

 

To which the man, confused, says "What... beef with black bean??"

 

 

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Darn it, Red... Hope it gets back on the boil soon...

 

Dunno where in London you were, Nev, but most convenience stores sell a vast array of refreshing drinks (both alcy and non alcy), and have a seemingly endless variety of water... And the women out here come from an equally vast array of different backgrounds... I was walking around Cannon Street yesterday at lunch time - I can certainly vouch for that (although I have a stiff neck - and before that prmpts comments, let's keep it clean)...

 

This morning - cloudy and cool... bummer!

 

 

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Yeah, a bit cloudy an cool down here in Tassie, too. Hoping it warms up to nearly 8 degrees about lunchtime tomorrow. And the gales might ease up enough for me to take the chainsaw out to attack the gum tree that fell across my driveway.

 

 

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Even up here in the sub tropics 30 deg south we have had some very cold nights (1-2 deg) and light frost. The sea water temperature is still 20 deg but this time of the year the wind is from the west so it is pretty cold on my morning walks on the beach with the dog. The good thing is that with clear sunny days the temp peaks at about 20 to 22 deg & so long as you are out of the wind it is beautiful. Inland though they are getting -5 to -10 temps & that is real brass monkey stuff. People think that because I came from NZ I'd be used to that sort of cold but in reality the minimums there rarely fall below 0 due to proximity to the ocean & mostlly are around 4 to 6deg but the maximums rarely get over 15 deg. The real difference is that Winter in NZ is the wet season so it always feels way colder than it is.

 

 

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London Jerry. I think a public tap or bubbler isn't too much to ask. They are everywhere here. Nev

Things I notice when I walk through the Sydney CBD:

 

1. No garbage tins - Where do people put their take-away drink containers?

 

2. No directions signs pointing to public toilets - You need them after taking more than an hour to travel into the CBD from the suburbs.

 

3. No bubblers - Got to support the plethora of coffee shops.

 

 

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