September_1966 — Page 69

Fig. 2. Measuring the transient deflection of road surfaces

ed by the Laboratory for use in tro- pical countries, are being used in the investigation in Malaya (Fig. 2).

The big advantage of the deflection beam as a method of test is that it provides a quick and convenient way of testing the whole road structure, including the effect of the strength of the subgrade soil underneath.

Preliminary results obtained from the investigation in Malaysia indicate that the roads now being built with dense crushed-stone bases are gener- ally of very good quality and will be capable of carrying the heaviest for- seeable traffic for at least the next 20 years. The roads constructed with bases of dense crushed-limestone are particularly good in this respect.

The Road Research Laboratory team is also working on the produc-

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tion of an engineering materials map of Malaya. This map will include in- formation on the types of soil occur- ring, the likely sources of roadstone, natural gravels, sands, laterites, etc.. and will be drafted with the needs of the road engineer principally in mind, A similar map covering Sabah. Brunei, and Sarawak was published in 1964.

A study is also in progress of the methods of constructing deep cuttings in tropical countries with high rain- fall such as Malaysia. Steep slopes are normally possible in the stiff soils that commonly occur in the areas of igneous rock, but the twin effects of surface erosion and the rapid soften- ing of newly exposed rock raise diffi- culties in some of the sedimentary rock areas.

T

Recently the Road Research Lab- oratory co-operated with Shell Malay- sia Ltd. in mounting two two-week courses in road engineering in Kuala Lumpur. The courses were attended by engineers of the Public Works De- partment from all over Malaysia. Lectures were given on topics rang- ing from road planning to road main- tenance and practical laboratory sessions in soil testing were held at the University of Malaya.

Acknowledgement

This article is contributed by per- mission of the Director of Road Re- search of the United Kingdom. Crown copyright. Reproduced by permission of the Controller of Her Britannic Majesty's Stationery Office.

Skid resistance value

80

7C

60

50

40

Granite in England

Granite in Malaya

Limestone in Malaya

30

2

3

t

5

5

Weeks

Far East Architect & Builder September, 1966

Comparison of the rate of polish- ing of roadstone in Malaya and England (heavily trafficked roads)

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