A Self-Learning Manual - Institution of Engineers Mauritius

A Self-Learning Manual
Mastering Different Fields of Civil Engineering Works (VC-Q&A Method) Vincent T. H. CHU
These beads are sprayed on the marking materials when the road is
marked. The beads are transparent and serve as lenses. When the light
passes through the beads, it is refracted through the beads and then
reflected back towards the original path of entry. The use of glass beads
enhances retroreflectivity which raises the safety level for night driving.
Fig. Glass bead in road marking
18. Why is hot applied thermoplastic road marking normally used
instead of cold applied road paint? (ORF6)
Hot applied thermoplastic road marking appears to be more commonly
used than cold applied road paint as road marking materials. For hot
applied thermoplastic road marking, it allows the addition of solid glass
head which enhances reflectorisation effect. This essentially makes great
improvement on the visibility of road markings at night time. Moreover, from
past experience the durability of thermoplastic road marking is higher than
that of road paint.
19. What are the advantages of using rockfill over earthfill to build
road embankment?
With the use of rockfill to build embankment, it is not a concern regarding
the build-up of pore water pressure during construction so that the
embankment can be filled at the faster rate. Moreover, the use of rockfill
allows a steeper angle in forming road embankment when compared with
earthfill so that it results in a small amount of fill. As such, it helps save the
cost of construction.
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