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What are the Types of Modifier in Bitumen?

By Nurul Hidayah

INTRODUCTION
Bitumen is a black or dark brown non-crystalline solid or viscous material, composed principally of high molecular weight hydrocarbons, having adhesive properties, derived from petroleum either by natural or refinery processes and substantially soluble in carbon disulphide. Refer to Ali Akhber Yousefi (2002), bitumen in pure form is not suitable for modern roads and present traffic, therefore forced engineers to modify bitumen to improve its performance during service life.

The modified binder are more stable under heavy loads, braking and accelerating forces and shows increased resistance to permanent deformation in hot weather. It resists fatigue loads and having better adhesion between aggregates and binders.

TYPE OF BITUMEN MODIFIER AND ADDITIVE

There are 3 type of bitumen modifier, namely :
(1) physical modification
(2) chemical modification
(3) other type modification

The table 1 below showed the type of modifier and example of additive that being used to modify the bitumen.
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A Study of Axle Overloadings On A Rural Road In Nigeria

By
S.S. KOLO, (Civil Engineering Department, Federal University of Technology, Minna, Nigeria), Y.A.JIMOH (University of Ilorin, Nigeria) AND P. N.NDOKE(Civil Engineering Department, Federal University of Technology, Minna, Nigeria)

Abstract
This paper presents the outcome of the axle load survey on a section of a rural trunk road in Nigeria in order to ascertain the contribution of overloaded goods vehicles to pavement failure. Seven day classified traffic and axle load survey was conducted for the determination of ADT, percentage heavy vehicle and the imposed axle load at respective axle position for the traversing vehicles on the Old Jos –Kaduna road, Kaduna state Nigeria. The proportion of the vehicle laden weight carried by each axle and the corresponding standard axle load (sal) was computed with the index model of power 4. The percentage and magnitude of overloaded axles were respectively determined as an indicative measure of the extent of structural damage to the pavement. The studied pavement was overstressed up to five times beyond the Nigeria standard axle load of 80kN, which was too high and hence constituting the hindsight to frequent structural damage to road pavements in Nigeria. It was recommended that the axle load control with weigh-in-motion weighing bridges to assure protection of the road from failure be instituted that will impact less disturbance to normal traffic flow on the arterial.

Keywords
Commercial Vehicle, Average Daily Traffic, Design life, Axle Load, Gross Weight and Gross Vehicle Weight
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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.

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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.

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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.