Page 40 - Lecture Notes DCC3113

Bitumen or Asphalt

Asphalt or bitumen is a dark brown to black, highly viscous, hydrocarbon
produced from petroleum distillation residue. This distillation can occur
naturally, resulting in asphalt lakes or occur in petroleum refinery using crude
oil. The primary use (70%) of asphalt/bitumen is in road construction, where it
is used as the glue or binder mixed with aggregate particles to create asphalt
concrete. Its other main uses are for bituminous waterproofing products,
including production of roofing felt and for sealing flat roofs.

Bitumen is graded according to standardised testing methods. Bituminous binders preparations most
commonly used are:
 Penetration bitumen: Grade of bitumen is determined by Penetration and Viscosity Test.
 Cut-back bitumen: Bitumen (60-85%) + light solvent (kerosene, gasoline, and naphthalene)
 Bitumen emulsion: Bitumen (55-70%) + water, either penetration bitumen or cutback bitumen.

Penetration graded bitumen

Bitumen is classified by the depth to which a standard needle will penetrate under specified
test conditions. This “pen” test classification is used to indicate the hardness of bitumen, lower
penetration indicating a harder bitumen. Penetration grades are listed as a range of penetration units
(one penetration unit = 0.1 mm of penetration by the standard needle). Specifications for penetration
graded bitumens normally state the penetration range for a grade, e.g. 50/70.

In Malaysia, use of 80-100 PEN is very common. However, the 60-70 PEN is recommended in the new
JKR specification. For cold climate regions, softer grade is preferred whereas hot climate demands
harder grade. Typical range of pen value is 40 to 300 PEN.
Penetration Graded Bitumen Grades in correspondence to ASTM D946-09 and EN 12591-2009,
including:

ASTM D946-09 Grades:
Bitumen Penetration Grade 40-50
Bitumen Penetration Grade 60-70
Bitumen Penetration Grade 85-100
Bitumen Penetration Grade 120-150
Bitumen Penetration Grade 200-300
EN 12591-2009 Grades:
Bitumen Penetration Grade 20/30
Bitumen Penetration Grade 30/45
Bitumen Penetration Grade 35/50
Bitumen Penetration Grade 40/60
Bitumen Penetration Grade 50/70
Bitumen Penetration Grade 70/100
Bitumen Penetration Grade 100/150
Bitumen Penetration Grade 160/220

Cut-back bitumen

Cut-backs are bitumen preparations in which the viscosity of the binder has been reduced by the
addition of a volatile solvent, normally derived from petroleum (bitumen that is dissolved in a solvent).
Typically the solvents used are white spirit Naptha, gasoline, and kerosene. Cut-back products are
typically used for spraying and some mixing applications. The type of solvent controls the curing
time while the amount determines the viscosity of the Cutback Bitumen.

The advantage Cutbacks have over Emulsions is a much higher residual Bitumen percent, typically
over 80% compares with over 40-65% for Bitumen emulsions.
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