Q3. (a) Sketch and name the road structure layers including the bituminous coating layers. State the material's CBR value and the degree of compaction (DOC) for each road layer required by road works specification. (5 marks) (b) The following data were recorded from field density test (FDT) on road base using sand replacement method. From the laboratory compaction test, it was noted that the maximum dry density of the sample is 2650 kg/m. Calculate the degree of compaction of the road base. (c) Mass of sand in the bottle (before test) = 8165 g (after test) = 5161 g Mass of sample from test hole. = 3810 g Density of sand = 1230 kg/m3 Mass of sand in cone = 1275 g Moisture content of soil = 7% (7 marks) A state road with a cement-treated road-base has been constructed on 1st November 2022. A week later, binder course (AC28) and wearing course (AC14) layer has been laid. Five days after opening to traffic, several road defects have occurred. Longitudinal cracks and a few portholes appeared on the road surface along 300 meters. Discuss the important factors during the road construction process that would lead to the aforementioned situation. (13marks) (25 marks)