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Peter Smith
Heating and ventilation engineer
Asked a question last year

What is the Diference between Semi Dense Bituminous Macadam (SDBC) and Bituminous Macadam (BM)?

What is the Diference between Semi Dense Bituminous Macadam (SDBC) and Bituminous Macadam (BM)?

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Bituminous Macadam is a Binder which is used for the 24-meter & 12-meter roads where the traffic movement is heavy. This can be laid in two or more courses for the better compressive strength. 

This shall comprise of 5 TO 7 percentage of bitumen. Semi Dense Bituminous Macadam is a binder that is laid after the BM course to obtain smoother finish on road surfaces. This is used in small roads of width less than 9 Meters. 

This course is laid directly on the wet mix macadam in smaller roads with a thickness of 25-30 mm. This shall comprise of 3 to 5 percentage of Bitumen.