Header Ads



DisAdvantage of Expansivity on Africa Road


   It is no longer a new thing that United States has good road for vehicles over Africa country which makes there car last long compare to Africa. Good road is very important for cars to last long other things are left for the owner. 

 90% of damage cars in Africa especially in Nigeria, is due to bad road and Some bad road is as a result of expansivity.

   Expansion/Expansivity occur usually in solid, liquid and gas. It requires temperature gained from a particular system. It simply called gain of heat. Which lead to an increase in the physical and chemical properties of a system. Either artificial heat or natural heat i.e "Sunlight" which is the major cause of expansion on road which lead to bad road in Africa.  

    Note;  when heating sands, it loses some of its components  such as oxygen and silica which made up silica dioxide know as quartz. In this process, these sands expand slowly to around 1063F i.e 573°C where the quartz (silica dioxide) undergoes a phase change to beta-quartz 2.

   The volume of the phase change is approximately 4.74% and 1.56% of linear expansivity. Generally means sunlight during the day without going off, expansion will take place.

   That's one of the major reason why will have day and night, which means during the day mostly dry season, Sunset is about 95% °C compare to Wet or raining season which makes expansion to occur in dry season and Condensation at night.

The same principal applicable in most Africa roads. But the major difference is the movement of cars on the road. Bitumens contain 79–88% carbon; 7–13% hydrogen, traces to 3% nitrogen; 8% sulphur; 8% oxygen by weight, but during sunlight all the components of bitumen expand in Africa, which makes them losing their quality more compare to sunset in United States.

  By the time of Condensation, the content of each components in bitumen will reduce generally makes the bitumen to lose quality.. 

  Typical example is: land and Sea Breeze

              Sea Breeze

  During the hot weather, heat from the sun passes straight from the air with little effect. The land is heated by the sun more quickly (especially in dry season) than the sea.

              Land Breeze

   During the night or cold weather, land cools very quickly because is loses heat to its environment. Temperature of the sea drops only slightly and since it has been heated to a very high temperature it remains heat as a forms of energy. With this, the sea is warm than land at night.

   Simple practical of this: pouring of hot water in a glass cup and wait for the reaction to take place.

Note; make sure you maintain some distance away from the cup after pouring the hot water to avoid injury.

      Advantages of expansion

  • Red-hot rivet in ship
  • Expansion of metals used in bimetallic thermometer
  • Fire-alarms
  • Removal of tight glass stopper
  • Fitting of wheels in rims

    Disadvantages of expansion

  • Cracking of Road
  • Expansion of metals or concrete bridge
  • Cracking of glass cup when hot water is poured into it.
  • Expansion of railway line


Post a Comment