compaction of bituminous material stoke jan 03.ppt

8/13/2019 COMPACTION OF BITUMINOUS MATERIAL stoke jan 03.ppt

1/15

COMPACTIONOF

BITUMINOUS MATERIAL

The HAUC Specification and the

Measurement of Air Voids

Phil Cartmail

Staffordshire County Council

evelopment Services


2/15

REASONS FOR

INTRODUCTION OF AIR

VOID SPECIFICATION

HAs have been left with a maintenance liability.

Allows retrospective judgement of workmanship. The appendix A8 method did not guarantee that

work was durable in the long term.

The rest of the industry, SHW,HAs, BS4987 now

specify voids.


3/15

Badly oxidised footway reinstatement


4/15

THE CHANGES

OLD CODE V REVISED CODE

METHOD

Materials Layer Thickness

Compaction Plant

Passes

END PRODUCT

Materials Lifts and Layers

Temperatures

Plantup to you !

Passesup to you !

AIR VOIDS !!!!!!!!!

But for work < 250mm wide a revised A 8 method still applies


5/15

HOW DO WE MEASURE

VOIDS ? Cut 150mm or 100 mm diameter cores

At least 75mm from reinstatement edge

1 core for small work < 2m2

Otherwise average of 3 values

Separate material layers

Measure density of material layer Measure material maximum density

Calculate air voids


6/15

CORE DENSITY

DETERMINATION

Weigh core in air(mass)

Seal core with wax, if needed, and weighagain.

Weigh core immersed in water.

Wt in air - Wt in water = Volume Mass / Volume = Density


7/15

Weigh corein air


8/15

Weigh corein water


9/15

Waterbath


10/15

MAXIMUM DENSITY

DETERMINATION Weigh sample in metal pressure vessel

Part fill vessel with water

Apply vacuum When all air has been removed top up with water

and re-weigh.

Empty and repeat process with water only

Volume of material is difference betweencontainer + material and container+material+water

Mass / Volume = Density


11/15

Maximumdensitysample

weighed intopressurevessel


12/15

Vacuumapparatus


13/15

AIR VOID

CONSIDERATIONS Maximum density samples may be bulk

samples taken at the time of supply or fromadditional cores.

For routine purposes it would be reasonablefor values from previous determinations tobe used.

In the event of dispute samples should betaken from the site in question.

Maximum density relates to a particularsource, mix and aggregate type.


14/15

Air Void Requirements:

Summary HRA & SMA -Surface Courses

c/way 2% - 8% : f/way 2% - 10%

CGWC - Surface Course

c/way 2% - 10% : f/way - NP HRA BC & DBC

c/way 2% - 10% : f/way 2% - 12%

PCSM c/way 2% - 10% : f/way 2% - 13%

DSC c/wayNP f/way 2% - 13%


15/15

Remember :so far as voids

are concerned

SIZE DOESMATTER !

compaction of bituminous material stoke jan 03.ppt

Documents