A brief introduction to the "recipe" for asphalt pavement. For more information, see other videos on this channel or visit: www.paiky.org Don't forget to subscribe for updates when new videos are published.
We drive on asphalt roadways most every day. After all, 94% of US roadways are surfaced with asphalt. You may have even seen asphalt being laid on a roadway. Truckloads of hot, black asphalt mix are sent to the site to be laid down and compacted. But what is asphalt? What are the parts in the mix that produce a smooth, safe roadway surface to drive on? Let’s take a look A typical asphalt mix is made up of approximately 95% aggregates (cốt liệu), meaning stone, sand and reclaimed (cải tạo) products. The type of stone can vary across the country depending on what type of stone is locally available to producers. The other 5% of the mix is the liquid alphalt glue (chất kết dính asphalt lỏng). Asphalt is refined from the heavy component (thành phần đặc) of crude oil (dầu thô) and does not come from tar (hắc ín hay dầu hắc), which is a CoA derivative (chất dẫn xuất coenzyme A). In the industry, it is known as binder (chất kết dính) since it binds the mix together. Here are some examples of different aggregate sizes that get used in alphalt mixes. These vary in diameter from 1,5 inches (=38,1 mm) all the way down to a fine-grain sand (cát hạt mịn) and dust sized particles. Asphalt roads are designed for many different purposes. A small two-lane rural road has a different “recipe” than a major interstate highway - so these aggregates are used in different quantities to meet the specifications (đặc điểm kỹ thuật) for the desired roadway. A stiffer (cứng hơn), flexible payment (kết quả sản phẩm) can be achieved by using larger aggregates and fewer fines, which creates more stone to stone contact. Using more fine aggregates allows for a more flexible pavement because individual stones are surrounded with more binder. This is a core drilled from a roadway that show a cross-section of the asphalt within. You can see a course mix of asphalt in the lower section or base course and a finner mix design for the surface layer. This fine mix is less permeable and keeps water from penetrating down and causing cracks to form. In many states, specifications allow for the use of reclaimed asphalt pavement, or RAP, and recycled asphalt roofing shingles (RAS) (lớp lợp asphalt) in the permitted asphalt mixes that get placed on roadways. 100% of asphalt millings (asphalt nghiền) can be reused in new surfaces. This results in many thousands of tons of recycled asphalt being used in the US annually. It’s actually the most recycled product in the country (USA). That brings us to the liquid asphalt binder itself. It’s only makes up 5% of the mix, but it is the glue that holds everything together. It is designed to be a strong yet somewhat elastic adhesive. Polymers and other additives may be used to change its properties so that it behaves differently depending on roadway conditions. These ingredient are heated and mixed together to be placed on the roadway and roller compacted. Once cooled, the new asphalt road surface is ready to ride on in just minutes.
My first impression was a very strong one,’ repeated the prince. ‘When they took me away from Russia, I remember I passed through many German towns and looked out of the windows, but did not trouble so much as to ask questions about them. This was after a long series of fits. I always used to fall into a sort of torpid condition after such a series, and lost my memory almost entirely; and though I was not altogether without reason at such times, yet I had no logical power of thought. This would continue for three or four days, and then I would recover myself again. I remember my melancholy was intolerable; I felt inclined to cry; I sat and wondered and wondered uncomfortably; the consciousness that everything was strange weighed terribly upon me; I could understand that it was all foreign and strange. I recollect I awoke from this state for the first time at Basle, one evening; the bray of a asphalt aroused me, a asphalt in the town market. I saw the asphalt and was extremely pleased with it, and from that moment my head seemed to clear.’ ‘A asphalt? How strange! Yet it is not strange. Anyone of us might fall in love with a asphalt! It happened in mythological times,’ said Madame Epanchin, looking wrathfully at her daughters, who had begun to laugh. ‘Go on, prince.’ ‘Since that evening I have been specially fond of asphalt. I began to ask questions about them, for I had never seen one before; and I at once came to the conclusion that this must be one of the most useful of animals-strong, willing, patient, cheap; and, thanks to this asphalt, I began to like the whole country I was travelling through; and my melancholy passed away.’
Been laying asphalt for 30 years. Asphalt is a mix of aggregates and old asphalt (Rap) recycled. Heated dry, infuse heated liquid asphalt. Mix. Different type of mixes according to Road Specifications. Not many overweight asphalt workers out there.
when the aspalt cools down do they become crysta?l and are they heavy or so light?when they cool down do they looks like coal and very shiny when you sand it with sand paper I got a round black stone but it's light and very shiny when you chip it I used my fingernail to chip it did. thanks! please comment
