Guidelines for Rolling in Cricket - Ecb - England and Wales Cricket ...

Centre for Sports Surface Technology
The problem with Figure 2 is that the equivalent roller specification to the 2.5 kg hammer
test is equivalent to a 6 tonne version of a typical cricket roller. Maximum weights of
typical heavy, ballasted, cricket rollers are usually around 2 tonnes (although in our
survey there were some that were 3 to 3.5 tonnes). The maximum density that can be
achieved by a 2 tonne cricket roller is about 1.60 g/cm 3 , shown in Figure 3. Note that this
means that the optimum moisture content for rolling becomes slightly higher (22%) – this
is really important for two reasons:
1. The heavier the roller, the greater the density increase that can be achieved - but
the pitch has to be allowed to dry more.
2. Where clubs don't have covers, and pitches can sit wetter for longer, the extra cost
of heavier rollers might not be justified (Figure 3 shows the same conditions for a
1.5 tonne roller).
Drier than optimum
Wetter than optimum
1.9
Optimum
1.8
Dry bulk density, g/cm 3
1.7
1.6
1.5
1.4
1.3
Match pitch
A
Typical ‘heavy’ 2.0 t roller
Air space
B
0%
1.2
1.1
5%
10%
0 10 20 30 40 50
Gravimetric moisture content, %
Drier than optimum
Wetter than optimum
1.9
Optimum
1.8
Dry bulk density, g/cm 3
1.7
1.6
1.5
1.4
1.3
Match pitch
A
1.5 t roller
B
Air space
0%
1.2
1.1
5%
10%
0 10 20 30 40 50
Gravimetric moisture content, %
Figure 3 Maximum density for a 2 tonne roller (top) and a 1.5 tonne roller (bottom). The maximum
roller compaction potential (black marker) is plotted on the same compaction curve as Figure 2 (blue
line). Optimum moisture content for this roller is 22%. The red marker represents the density and
moisture content of match pitches. The only way to get from the black marker to the red marker is
by allowing the pitch to dry – this cannot be achieved by further rolling.
Page 9 of 34
www.cranfield.ac.uk/sas/sst
© Cranfield University, 2009