QAQC CIVIL ENGINEERING

  DBM (Dense Bituminous Macadam) is a part of  flexible pavement and the work shall consist of construction of single or multiple layers on wmm or sub base. The thickness of single layer shall be 50mm to 100mm as per MORTH specification. According to MORTH 5th rev. Table 500-10 , There are Two grading are specified for DBM construction (1) DBM Grading-1  Grading-1 is suitable for layer thickness of 75 mm to 100 mm and 37.5mm nominal size of aggregate shall be used. Bitumen content by mass of total mix = 4 % minimum (2) DBM Grading-2 Grading-2 is suitable for layer thickness of 50 mm to 75 mm and 26.5 mm nominal size of aggregate shall be used. Bitumen content by mass of total mix = 4.5 % minimum Reference code and specification MORTH 5th Rev. Asphalt Institute Manual MS-2 ASTM-D6926 ASTM-D6927 ASTM-D5581 IS-73-2013 IS-1201-1220:1978 ASTM-D2041 AASHTO-T283 DESIGN MIX OF DBM GRADING-1 (Dense Bituminous Macadam)   Thank You for Visiting