There are many factors that determine pavement design. this includes the following :-
- Axle configuration – in car design providing more axles enables it to carry more load, this more load needs to be pre-determined in design. this ranges from single unit trucks, convectional combination vehicles & longer combination vehicles.
- Wheel load – this is very important in being able to determine pavement thickness. it is deemed necessary to know so that not to affect the sub grade during traffic.
- Contact pressure – Tire contact pressure on pavement is a key factor in pavement design since a pressure is created between pavement and tire. when the tire has low pressure then contact pressure will be higher than tire pressure. in a high pressure tire, then contact pressure will be less than tire pressure.
- Vehicle speed – vehicle speed is a determining factor in pavement design. high speeds case creep while small speeds cause small damage to roads.
- Type of sub grade – various tests are performed like tri-axle test, C.B.R test to test quality and structural integrity of sub grade and its thickness because its deemed necessary to pre determine it in design.
- Temperature – change in temperature causes expansion and contraction leading to cracks in asphalt roads. it is therefore an influencing factor in design.
- Precipitation – Moisture from rain affects depth of ground water table hence causing damage if exceeding a certain level. proper drainage must therefore be administered
- Repetition of loads – traffic and the repeated loads cause deformation in roads hence it is also deemed necessary in design to pre-determine this.
This are the few major factors that should be determined in design of a road. to find out more about road defects visit my pavement road defects article . if you want to know more about the types of roads visit my types of roads page.