NRSWA Reinstatement Compacting & Backfill Practice Questions – Set 1
#1. What class of Backfill is Graded Granular?
#2. What is the maximum compacted lift thickness for GSB 1?
#3. How many passes would be carried out when using a 56Kg Vibrotamper on 100mm of GSB 1?
#4. What is the weight of a percussive rammer?
#5. The class C material being stored on site for re-use becomes extremely wet, what class would it then become if a field ID test was carried out?
#6. If using a class B material in the backfill layer, what would be the minimum depth of the sub-base layer in a flexible carriageway?
#7. What would be the structural layer thickness tolerance if using an unbound material?
#8. What should be placed immediately on top of the fine fill layer surrounding a utility service?
#9. Why do you add a surcharge of material (approx. 25%) to each layer prior to compaction?
#10. What would be the overall depth of excavating the construction layers in a Type 4 Flexible Carriageway, if a Class B backfill had been used?
