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HI Guys

First off, I am a resident of HK and been a member of SSC for many years. This is my first posting in HKSSC. I would like to know if anyone of you could give me the technical details as to what kind of concrete grade and other mixtures that are used to build concrete roads in Hong Kong?

The reason is that I have found HK roads are built at a very fast rate due to the quick drying of concrete after laying. In third world countries or developed countries, concrete used takes 3-4 days of curing with water paddies made on the surface to retain water.

Also - what kind of concrete is used for buildings exterior and interior walls? Observed that these too dry and set very quickly thus rate of build-up is quicker.

Any knowledgeable replies to this post will be highly appreciated.

Regds
p2p4
Hong Kong
 

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HI Guys

First off, I am a resident of HK and been a member of SSC for many years. This is my first posting in HKSSC. I would like to know if anyone of you could give me the technical details as to what kind of concrete grade and other mixtures that are used to build concrete roads in Hong Kong?

The reason is that I have found HK roads are built at a very fast rate due to the quick drying of concrete after laying. In third world countries or developed countries, concrete used takes 3-4 days of curing with water paddies made on the surface to retain water.

Also - what kind of concrete is used for buildings exterior and interior walls? Observed that these too dry and set very quickly thus rate of build-up is quicker.

Any knowledgeable replies to this post will be highly appreciated.

Regds
p2p4
Hong Kong
On the road portion, the typical for the surface slab is grade 40/20.
There are some more technical information on the Highway Department webpage:
http://www.hyd.gov.hk/eng/public/publications/guidance_notes/index.htm

The traditional concrete pavement is less used these days in Hong Kong. These are where you see they are grey surface. Although concrete pavement are more durable, and last longer with less maintenance; but they are more noise and take longer to construct. In HK, since so many roadways are close to people and always busy, keep the noise down and construction time down have become more important. Therefore, the trend has switched to use what calls bituminous concrete.

Bituminous concrete or asphalt, aka "black top", is where you see they are black surface. This is much easier to build using heat and pressure; and can be opened to use in only hours after it laid out.

Some more specific documents for what you are interested:
Design Guideline:
Unreinforced Concrete Slab for Rigid Pavement:
http://www.hyd.gov.hk/eng/public/publications/guidance_notes/pdf/gn013.pdf

Pavement Design
http://www.hyd.gov.hk/eng/public/publications/guidance_notes/pdf/gn017.pdf

Mix Design of Bituminous Materials
http://www.hyd.gov.hk/eng/public/publications/guidance_notes/pdf/gn022.pdf

Road Surface Requirements for Expressways and High Speed Roads
http://www.hyd.gov.hk/eng/public/publications/guidance_notes/pdf/GN032.pdf


Typical details:
http://www.hyd.gov.hk/eng/public/publications/stdraw/section1.htm

Materials:
Bituminous Materials
http://www.hyd.gov.hk/eng/public/publications/bituminous/index.htm

Not too sure about the building portion of your question, but I would say building aren't as standard as the road, since each building carries a different loading and requires different concrete strength. That's my two cents.
 

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EiGhT 5 & tWo
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Hey Eric,

I know in some other developed countries like Japan and Singapore, Bituminous is commonly used for building roadways. But as we can see In HK, Bituminous is obviously not widely used as the raw material of roadways and pavements (except highways), I wonder if it's because of the high construction and maintenese costs, or there are some other reasons that I don't know.

By the way, the traditional concrete pavement looks bloody shabby in my eyes, so I hope this kind of raw material will soon be replaced by Bituminous.
 

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Hey Eric,

I know in some other developed countries like Japan and Singapore, Bituminous is commonly used for building roadways. But as we can see In HK, Bituminous is obviously not widely used as the raw material of roadways and pavements (except highways), I wonder if it's because of the high construction and maintenese costs, or there are some other reasons that I don't know.

By the way, the traditional concrete pavement looks bloody shabby in my eyes, so I hope this kind of raw material will soon be replaced by Bituminous.
Even in the US, at least where I am in now, bituminous is basically the only choice of materials for roadway construction. Concrete is not even considered, except in extreme rare case.

For Hong Kong, I can't say my answer is 100% correct, but just from what I can think of...
The major problem of bituminous is it gets torn apart by heavy loading (vehicles) rather quick compare to using concrete. Our urban environment is full of these heavy double deckers, which probably is the world densest.
Although bituminous is more quite and easier to construct, but it requires constant maintenance years after years. This may actually be even more troublesome to shut down the busy urban roadways than just use concrete which last significantly longer and maintenance "free."

Would you rather see construction equipments and lane closure everyday on different part Nathan Road/Hennessey Road everyday? Or would you rather look at the less noticeable concrete? But away from the most important urban trunk roads, I do notice bituminous is more common in HK these days.

The other advantage that bituminous has over concrete is, bituminous provides better traction for skid resistance compares to concrete. Especially on high speed expressway.

I am sure there are guidelines from the Highway Department listing when to use concrete and when to use bituminous, just have to find it.
 

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I thought bitumen is more common.

Given that HK's roads are constantly dug up anyway... I suppose it's not a huge problem using bitumen?
That's what I thought at first; then I started to going through all these street pictures everyone posted in the forum. I realized all the small streets (e.g. Lockhart Rd, Sai Yeung Choi St etc.) and major trunk road (i.e. Nathan Road, Hennessy Road, Des Voeux Rd etc.) are all concrete pavement. But at the same time the expressways, tunnels, rural roads and other high speed urban trunk roads (i.e. Connaught Rd, Gloucester Rd) are all bituminous.

So both are common in place depends on the area and usage. I guess we have that wrong impression because we always see these heavy equipments doing milling and resurfacing on the roads for bituminous, but you don't see any for the concrete portion.
 

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EOS 40D
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HK has a disproportionately large amount of heavy vehicles using the roads. This is due to the prevalence of mass transit and goods vehicles.

I think the type, quality and grade of the asphalt is important too. In the US lots of roads are blacktop, but they still have decent lifespan even with heavy vehicles.
 
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