Quality management of embankment, subgrade and unbound sub-bases/bases

Quality management systems are needed during the construction of embankments and the subgrade and roadbase of highways in order to prevent future problems. Quality management issues relating to site clearance during road widening are outlined. Quality management issues relating to the selection of a good soil for embankments and subgrade are considered with reference to soil formation, soil particle size, soil activity, soil sulphur content and soil characteristics, classification and identification. Quality requirements for embankment construction and compaction control are outlined. Quality issues relating to the selection of subgrade soil are considered: liquid limit and plasticity index, subgrade strength, compaction control, and California Bearing Ratio (CBR). The application of the MORTH specification to granular subbases is discussed. Quality issues relating to dismantling bituminous and subbase/base materials, drainage layers, wet mix macadam, and construction processes are considered.