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A Comparison of Marshall Properties of Various Types Of Cold Mixes Found In Nigeria

By
S.S.Kolo(1)andy.Ajimoh(2)
Dept.Ofcivilengineering
1. Futminna
2. Unilorin

ABSTRACT
This study present, the Marshall properties of the cold mix asphalt produced with the DPWS modified bitumen were compared with those of the commercial cold mixes in use in Nigeria. The following Stability and flow result were obtained after careful laboratory experiment; for the DPWS modified cold mix Asphalt a stability of 5.8KN and flow of 4mm were obtained when using the normal hot mix method of testing, while stability of 9.58KN and flow of 4.5mm were obtained when air dried method was used. The Portland Emco shows stability of 2.21KN and flow of 3.95mm when it was subjected to test using the normal hot mix method of testing, while a stability of 4.37KN and a flow of 4.85mm were obtained air dried method was used. The Carboncor shows stability of 4.27KN and flow of 5.5mm when it was subjected to test using the normal hot mix method of testing, while a stability of 9.79KN and a flow of 5.5mm were obtained when air dried method was used. The UPM could not be tested for stability when it was subjected to test using the normal hot mix method of testing, but using the air dried method a stability of 1KN and a flow of 6.85mm were obtained. This shows that the modified cold Asphalt has a good strength when subjected to worst condition.

Keywords: Marshall Properties, Stability, DPWS, Cold Asphalt
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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.

This question is taken from book named – A Self Learning Manual – Mastering Different Fields of Civil Engineering Works (VC-Q-A-Method) by Vincent T. H. CHU.

Why is hot applied thermoplastic road marking normally used instead of cold applied road paint?

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.

This question is taken from book named – A Self Learning Manual – Mastering Different Fields of Civil Engineering Works (VC-Q-A-Method) by Vincent T. H. CHU.

What is the importance of glass beads in road markings?

Retroreflectivity refers to the part of incident light from headlights of a vehicle being reflected back to the driver. Retroreflectivity is normally achieved in road marking materials by using glass beads or ceramic beads.

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.

glass-bead-on-roads

This question is taken from book named – A Self Learning Manual – Mastering Different Fields of Civil Engineering Works (VC-Q-A-Method) by Vincent T. H. CHU.

What is the purpose of road studs in roads?

In nighttime, car drivers could not see where the road ends and where the alignment of road changes in direction. Without sufficient number of road lightings, it is necessary to provide some means to guide the drivers along dark roads. Hence, in 1933 Percy Shaw invented the cat’s eye (i.e. road studs) which is based on the principle of cat’s eyes. When a ray of light enters the eyes of a cat, the light shall be reflected back towards to the emitting source. As such, with the reflection of car’s headlights by road studs, it is possible to identify road conditions and alignment in darkness.

However, the provision of cats’ eye is not without problem. For instance, there have been reported accidents arising from loosely installed cat’s eye. Some new design of cat’s eye uses LEDs which flash at about 100 times per second. However, it is claimed to cause epileptic fits of drivers.

This question is taken from book named – A Self Learning Manual – Mastering Different Fields of Civil Engineering Works (VC-Q-A-Method) by Vincent T. H. CHU.