Given: the data shown in Fig. 5.4 Soil types 3 and 4 are mixed in the borrow area to some unknown extent. After a representative sample of the combined material is air dried to a uniform water content (hopefully on the dry side of optimum), a compaction test is performed and a value of 1.85 Mg/m3 dry density at 12.5% water content is obtained.

(a) Estimate the maximum dry density of the combined soils.

(b) If a field dry density of 1.54 Mg/m3 is obtained after compaction by a sheepsfoot roller, compute the relative compaction.?