In fact, now some asphalt roads will also stick feet, last year our local circle of friends went viral a video, a young man wearing slippers to cross the road every step of the shoe is stuck, three or four steps hard to walk for a minute, and finally the shoes are also stuck. The people who made the video laughed. But in general, the quality of the asphalt road should be better than before, and I think there should be these reasons.
The main material of asphalt road is asphalt, asphalt mainly comes from the by-product of petroleum refining, and some people may wonder when it comes to this, since it is asphalt, why is it called asphalt road? Because there is also a kind of asphalt that is a by-product of coal tar production, called coal asphalt. At that time, people used to call this thing asphalt. Coal asphalt is soft in summer and hard in winter, and its performance is not as good as petroleum asphalt. Although petroleum asphalt is better than coal asphalt, the refining technology is not good that year, and the oil asphalt wax content is high, resulting in high temperature and easy softness. Now that the refining technology is good, the performance of the asphalt has also been improved, and it is not easy to stick to the feet when paving the road.
Asphalt roads are paved and compacted with a mixture of asphalt and gravel. After paving, the surface sealing layer needs to be done according to the situation, that is, pure asphalt is coated on the surface of the road to fill the stone gap to achieve the effect of waterproofing, and this layer of asphalt is easy to become soft at high temperatures. Generally, the waterproof requirements are high and the surface sealing layer is needed, and the drainage conditions are good, and the asphalt-coated pavement is of course sticky.
In the past, such repair marks were often seen on the road, which were all traces of asphalt after the road cracked, and what was made up was pure asphalt, and some places cracked the area was too large or even covered with a large piece of asphalt, so that maintenance was very convenient, a tractor pulled a large pot of burning asphalt and then took a few scoops to dry the work. These asphalts become soft and sticky to the feet in the summer. I remember when I was a child, I often saw patches of black asphalt on the road. Friends like to wear sandals to step on the footprints, feel the asphalt sticking to the shoes crunching feeling. I used to cross the road and have my shoes glued off by asphalt. What a wonderful childhood.
And now the degree of mechanization is high, some of the road surface disease is serious, directly on the road milling machine, a trip to the past the old road surface will be cut off a layer, directly paved with a new layer of pavement, the roller pressed several times after the soon open to traffic. This was unimaginable at the time.
The above figure of this road roller after 80 friends should have the impression, the road construction is the most common this three-wheel roller, this is a static pressure roller, that is, can only rely on their own weight to compact the road surface, for this paving when the asphalt and stone mix can not be too hard, otherwise it is not good to compact, remember when I was a child to see the municipal paving, the asphalt and stones pulled are hot, some cars are even on fire, it is said that the asphalt content is high, so that it can ensure that the paving is not so hard, easy to compact.
Now there are too many construction machinery, and it is more convenient to build roads. For example, the tire roller in the picture above, its tire grounding area is smaller than the large steel wheel of the roller, so it can produce a large pressure, and when pressing the road, it can have a rubbing effect on the stones and asphalt, so that they are more tightly combined. And now the static pressure roller has long disappeared, replaced by a vibratory roller, the drum has a vibrator, can provide pressure several times greater than its own weight. So the material does not need to mix too much asphalt. I remember that a few years ago, I saw the repair of the national highway pull asphalt stone car unloading after the car unloading basically no large area attached.
From the road can also see the national economic level, a few years ago we built the national highway here, I actually followed the machine to see for an afternoon, that speed, that equipment, that efficiency, is really enjoyable.