[ChiragM]

The first concrete road in India is said to have been built by the British in Chennai in 1914.

Today, we are seeing a lot of arterial roads converted from asphalt to concrete roads. Most driving enthusiasts prefer asphalt, but the government seems determined to convert as many roads as possible to concrete.

Concrete Roads

Made of aggregates (crushed rock, sand & gravel), cement and water. Often reinforced with steel bars within the concrete.


Advantages

• Concrete roads have a lifespan of between 20 to 40 years, which is two to four times longer than asphalt
• Since concrete roads handle weight well by being less prone to dips & rutting, they are better suited to roads with high truck volume
• As there are lower chances of potholes forming, traffic flows smoother, and it's safer for motorists too
• Vehicles have been tested to return between 1-7% better fuel efficiency on concrete roads, since the road doesn't deflect as much under weight
• Production of concrete roads is a relatively more environment friendly process
• These roads do not get weakened or damaged by oil leaks, unlike asphalt
• Concrete is more resistant to the freeze-thaw cycle and can hence be used in cold temperatures
• Can be considered recyclable, to the extent that the old concrete road slabs can be ground up and used as gravel

Disadvantages

• Repairing concrete is a pain. Holes and cracks can't be patched. Entire slabs need to be re-worked
• It costs more and takes longer than asphalt for both construction as well as repair
• Concrete roads result in a bumpy drive, as slab levels can differ slightly and expansion joints are felt too. Worse if you have a car with a harsh ride
• Texture is brushed onto the surface of the concrete, so in addition to the rhythmic bumping of the slab joints, this also creates a lot more road noise
• These roads don't offer as much grip as asphalt does. Vehicles are likely to lose traction slightly sooner on concrete
• Due to improper laying of the roads, some concrete roads have wide longitudinal joints between slabs. This has become extremely dangerous for two-wheelers
• Harsh reflectivity of concrete roads can make driving on them a strain on the eyes on extremely sunny days
• The surface does not absorb spills, chemicals and other pollutants like asphalt does
• In winter and rainy conditions snow does not melt as fast and water does not evaporate as quickly due to its lower heat absorption

Asphalt Roads

Made up of aggregates (crushed rock, sand & gravel), binder (bitumen) and filler.


Advantages

• Asphalt roads are cheaper to build and the entire process takes less time
• It is easier to repair and maintain them as well, since they can be repaired in patches
• The road surface offers better traction and skid resistance than concrete roads, thus making them safer in certain dynamic situations
• Driving on asphalt roads generates less road noise and is much quieter than concrete roads
• Higher heat absorption helps snow melt faster and moisture evaporate faster
• Asphalt is also recyclable, as it can be melted down and re-used for road surfacing

Disadvantages

• Asphalt roads have a 10-year lifespan, so they need to be re-laid or repaired more regularly than concrete roads
• Heavy rains can cause significant damage to the road surface, which is something we have all witnessed during the monsoons
• Oil leaks on the road eventually weaken the binding agent in the asphalt, making the paving softer and more prone to damage
• Melting asphalt during the construction stage emits greenhouse gases. It causes more pollution while building when compared to concrete roads
• In harsh winters the freeze-thaw cycle can destroy asphalt roads. The road becomes less flexible and more brittle in cold weather

A closer look at the section of a concrete slab. Note the thickness of the slab, and the reinforcing steel bars:

Image Source

One of the main reasons why the government is shifting to concrete roads - longevity and lower chances of potholes:

Image Source

Most driving enthusiasts love the look & feel of perfectly smooth black-top. However, do you think the advantages of having concrete roads outweigh the advantages of asphalt roads?

Reference 1
Reference 2
Reference 3

[Rehaan]

Thread moved out from the Assembly Line. Thanks for sharing!


I'm a big fan of smooth black tarmac. Concrete roads just don't have any charm in comparison.

I think if the government just did a better job of the actual construction of the asphalt roads, they'd last a lot longer and wouldn't look like uneven patchwork quilts.

I can certainly see the push for concrete roads coming from an eco-friendly standpoint. A 1~6% increase in mileage is massive when you look at the number of cars that ply on these roads daily, and the distances involved. Pretty amazing that the tiny difference in the rigidity of the road can affect the rolling resistance of tyres so significantly!

[batish]

You missed the tyre heating point. Concrete tends to generate more heat in tyres than bitumen. So in a way it is way less forgiving then asphalt if the tyre pressures are low. One of the reasons why Yamuna Expressway has higher than usual rate of tyre failure.

[Thermodynamics]

Nice thread. Concrete roads have merits but nothin like well laid asphalt road when it comes to driving long distances. Can’t imagine the tyre noise for 10 hours straight.

I have a second thought on eco friendly argument. Asphalt is a byproduct of refinery that is put to some good use, whereas cement has to be produced and that is not eco friendly. So much carbon goes into calcining limestone. Wear and tear of tyres will be faster on concrete roads and production/disposal of tyres aren’t eco-friendly either.

Also from a safety perspective, Concrete roads cause higher frequency of accidents due to tyre bursts, inadequate braking/traction and even due to exposed steel bars.

On the other hand, concrete roads are more reliable, fuel efficient and also more weather-able for example in a heavy rain/water flow asphalt is more likely to cave in.

[speedmiester]

I would any day prefer a tarmac road over concrete road.
If the tarmac roads are built properly with proper excavation, they can last a long time.
Longevity should not be the only reason to shift to concrete.

The lack of grip and road noise on concrete roads really spoils the fun of relaxed driving. The tyre wear is also higher on concrete roads.

[GTO]

As other BHPians said, I love a pure, clean asphalt road as well . Superior grip, especially in the rains too. Nothing quite like pushing a tight hatchback or fast handler on tar roads. The tyre noise is also lesser.

Imagine a 300 BHP 6-cylinder AWD on such a road?


Even better, a Cooper S on WET asphalt

[Axe77]

I HATE concrete roads, even more so on a motorcycle. I somehow feel far less confident on a sweeping turn on concrete than I do on asphalt.

The tyre noise is annoying and the quality of some of our flagship expressways isn’t anything to write home about (on the flip side I wonder how bad it would have been if it was undermaintained asphalt).

Finally, I also find concrete tiring on long rides because of its color - I find asphalt easier on the eye if I am doing a LONG road trip. Not sure if that makes sense to everyone.

[Malyaj]

I have driven on some badly laid out concrete roads (can't remember which stretch). The problem was that the surface cement was spread longitudinally (in the direction of drive) as if with a fork, which caused the car to shimmy left and right at the slightest steering input. This was extremely dangerous at high speeds. Think of a train constantly changing tracks.

Asphalt roads, while not as durable as concrete have a worse reputation than deserved in our country. I remember Old Airport Road in Bangalore being a terrible patchy surface until one day a VVIP visited ISRO and the road was relaid with asphalt. Knowingly or unknowingly they did such a good job that the road survives till today without potholes, despite crazy traffic and heavy rains.

[Prowler]

The dumb earlier state government laid concrete roads in our locality. Many people complained at that stage that the concrete surface will start shedding cementitious dust which when airborne will affect our lungs resulting in increased incidence of asthma, emphysema and COPD. May be concrete roads are preferred in highways but surely not for residential areas.

Probably one of the oldest concrete roads in India is the road from Coimbatore to Mettupalayam laid some time during the 1960 when PM Nehru visited Nilgiris along with Canadian Engineers for the Kundha and other Power projects. They repaired the concrete roads with asphalt all these years.

[gkveda]

As a driver, Ride quality and road grip are two most important factors while driving. These are 100 times better on asphalt roads compared to cement roads.

But, as a road construction engineer, the longevity is definitely a most important factor to be considered while choosing the road. Longevity is definitely 5-10 times more for cement roads compared to asphalt roads. I have seen cement roads, in the same new condition even after 40 years of initial construction.

In fact, maintenance cost for reconstruction of asphalt roads over a duration of 10 years will almost equate the construction cost of the road.

So, my thoughts on striking a balance is, to have an asphalt layer of required thickness on cement road. This might cost more initially but considering the longevity of the road, this may work out cheaper. Also, it gives the smoothness of asphalt roads to the drivers.

[Raghu M]

I have one more very important point. Falling from a bike while doing reasonable speeds, you tend to get badly hurt on concrete roads. Even a small fall will make for a great damage. While the asphalt roads tend to be a bit smoother when you have a fall. That's my observation as I have had personal experience too. I scraped my knee badly while running on concrete road, it would have definitely not been that bad on a normal road.

[SmartCat]

Mod note: Poll added. Please vote!

Originally Posted by ChiragM

Concrete roads have a lifespan of between 20 to 40 years

We need to put a star here with the fineprint: "not applicable to concrete or asphalt road between Bangalore & Mangalore". That's why we have a thread titled "the art of travelling" between..
https://www.team-bhp.com/forum/route...ore-udupi.html (The art of travelling between Bangalore - Mangalore/Udupi)

[Yusha]

Originally Posted by ChiragM

A closer look at the section of a concrete slab. Note the thickness of the slab, and the reinforcing steel bars:

Attachment 2147216
Image Source

Concrete roads do not have steel rebars. The steel rod you see protruding out of the side is provided for expansion and is known as a dowel. They will put a round plastic sleeve when they cast the other slab and the steel bar is inserted in the plastic sleeve which allows for movement.

[V.Narayan]

Asphalt roads in India suffer from the connivance of contractors and municipal {or other relevant Govt department} officers. In parts of Delhi NCR such as Faridabad, Gurgaon the nexus works as follows - Step 1 - build road to a poorer standard than needed. Step 2 - Wait for the rains. One strong shower and roads in these areas get full of potholes because they are designed for it. Step 3 - Contractor get a fresh work order in 6 to 9 months. Step 4 - see Step 1. By re-building or paving the same stretch 4 times in 2 years instead of once in 5 years all parties benefit, more loot to go around. More happy smiles. Did I say all - oops sorry forgot the taxpayer, that stupid chap.

For this reason I prefer concrete roads. For some reason they seem less amenable to fudging the quality. Not sure why but that is my observation.

Yes, asphalt roads have superior grip and are less slippery when wet. But I don't drive at 80 kmph in the rains so at least for me concrete works just fine.

[PPS]

Prefer a well laid Asphalt road anytime. Have driven on the Mumbai-Pune Expressway several times but had a lot more fun & enjoyment while driving from Lonavla to Talegaon on the Old Highway. The levelling of that road was brilliant compared to the Expressway! Even Mumbai-Nashik was an enjoyable experience.