Q 4 You Work For A Highway Engineering Firm Where Your Role Is To Bring Benefits To Projects By Incorporating Non Specif 1 (74.64 KiB) Viewed 21 times
Q 4 You Work For A Highway Engineering Firm Where Your Role Is To Bring Benefits To Projects By Incorporating Non Specif 2 (14.02 KiB) Viewed 21 times
Q.4 You work for a highway engineering firm where your role is to bring benefits to projects by incorporating non-specified materials such as secondary aggregates into road pavement design. (a) State the design process that allows for use of non-specified materials in a road foundation and outline the key features of this process. [3 marks) (b) You identify two potential foundation materials for use in the foundation of a new single carriageway road pavement that is 5 km long, has an average paved width of 9.3 m, and has a design traffic loading of 16 msa. The two materials are: • Type 1 aggregate certified as foundation class 2 (E = 100 MPa), sourced from a distant quarry. • Locally available secondary aggregates with a stiffness of E = 56 to 60 MPa. i) For both potential foundation materials, use the Standard Upper Pavement Design method and nomograph in Figure Q4 to calculate the total thickness and total volume of upper pavement material, assuming this will be AC 40/60 asphalt material. [6 marks] ii) Discuss the relative merits and disadvantages of the two designs. [4 marks] Figure Q.4 Traffic (msa) . 30 HEM Category Foundation Class Asphalt Material AC 4010 EME b 150 300 200 250 Flexible with HBM Base Thickness (mm) of HOM Base MO 170 Flexible with HBM Base. Total thickness (mm) of asphalt 200 300 400 Flexible with Asphalt Base Total thickness (mm) of asphalt PLEASE TURN OVER
(c) State in which layer of the road pavement porous asphalt might be used and describe the benefits and drawbacks of porous asphalt. [4 marks) Explain why we only consider commercial vehicles when calculating design traffic and why commercial vehicles are divided into different classes. [3 marks1 (d)
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