Proctor compaction test in the laboratory on a borrow pit soil gives a maximum dry unit weight of 19 kN/m3 and optimum water content of 11.5%. The bulk unit weight and water content of the soil in the borrow pit are 17.2 kN/m3 and 8.2%, respectively. A highway fill is to be constructed using the soil. The specifications require the fill to be compacted to 95% Proctor compaction.

(a) How many cubic meters of borrow pit material is needed for 1 m3 highway fill (i.e., compacted soil)?

(b) The water content at 95% compaction is 11% on the dry side and 12% on the wet side of the compaction curve. What is the minimum additional weight of water per unit volume to
achieve 95% Proctor compaction?

(c) If the soil were expansive (i.e., volume increases with water content), what is the additional weight of water per unit volume to achieve 95% Proctor compaction?

(d) How many truckloads of soil will be required for a 100,000 m3 highway embankment? Each truck has a capacity of 10m3.

(e) Determine the cost for 100,000 m3 of compacted soil based on the following data:

Purchase and load borrow pit material at site, haul 2 km round trip, and spread with 200 HP bulldozer = $25/m ³ ; extra mileage charge for each km = $3.10/m3; round trip distance = 10 km; compaction = $1.02/m ³ .