2.3   STRUCTURAL DEVELOPMENT OF PAVEMENTS AND EXPERIENCES

 

The pace of progress cannot be overlooked - it was not achieved easily or cheaply. The problems and difficulties which the Roads Department in its first 28 years and thereafter the Department of Transport since 1980 and the Ministry of Works, Transport and Communication since the date of independence encountered were sometimes demoralising, often unique and always onerous. Namibia is a land of many faces: from inhospitable desert and hard rocky outcrops to rugged mountains and undulating plains. Each of these presented different problems to the road builder - some areas, barren and waterless, while others offer -one of the biggest structural problems- no conventional road building materials. Substitutes had to be found, new techniques had to be devised and applied and many innovations had to be developed. Due to its experience in unused and widely diversified conditions the Ministry is today recognised as a world authority on certain aspects of road construction.

In the German colonial times no roads with structured layerworks were built, only some ox-wagon tracks here and there improved by "pick and shovel" methods. This situation remained unchanged deep into the 1920s during the South African colonial times. In the reports to the League of Nations no mention is made of roads until the year 1925, when an amount of R 766,44 was provided for under the Public Works Vote [10] (One British Pound is taken as two South African Rand, as has been the official Pound/Rand relationship when the Rand was firstly introduced in 1961. Currently 1 US $ equals R 2,63 (December 1989)). During 1927 [11] it was, for instance, stated: "... that nobody should expect that South West Africa's roads system would be the best in the world because the character of the country would be against the construction of first class roads. Responsible for this would be an abundance of mica schist and sand and the scarcity of good road building materials. In Owamboland, for instance, not a single stone could be encountered, except in the vicinity of the Kunene River. The building of a modern highway from the north to the south of the territory would cost hundred thousands of pound sterling, which the administration never could afford to spend".

The first roads which were improved by mechanical means were earth roads which were graded by mule drawn and later tractor drawn graders. No structured layerworks were applied at this stage. The first tractor drawn grader was purchased during the financial year 1932/33 by the Works Branch of the Administration for South West Africa for the maintenance and repair of Namibian roads. In 1932 two maintenance units were brought into being with the help of two second-hand lorries, a 5 ton " Federal" and a 2 ton " Reo" in the Windhoek district. The first light motor grader, a Galion, was purchased in 1936. The exact distances of main and district roads in existence at this stage were not recorded [10].

In 1937/38 the first two Caterpillar II motor graders were purchased as well as a motor driven three wheel roller. An additional Caterpillar II grader was purchased in 1939. By 1940, four heavy motor graders, one crawler tractor, one 5/8 cub.yds. truck mounted loader, several tractors towing 3 ton drawn graders and a number of trucks were in operation.

After the Second World War the South African " Public Service Commission" for the first time made professional and technical personnel available to the Work's Branch of the Administration. This enabled the detailed survey, location and design of roads and bridges and marked the beginning of programmed road building activities in Namibia. To this point of time the construction and maintenance of roads was restricted to the grading of earth roads and tracks. No detailed records of the improvement of earth roads by selected road building materials exist.

In spite of an amount of R 615.000,00 spent out of the Roads Fund in 1950 there were still many shortcomings in the roads system of Namibia so that the Executive Committee appointed a commission to go into this matter. Speaking of paved roads the Commission recommended as follows:

"Although tarred roads are more expensive than gravelled roads, the Commission feels that tarred roads would be a boon to the country, and would advance the attempts of real road-building already being made. Elsewhere we mention that a sound start has been made with 500 miles of road, and we now recommend strongly that these 500 miles should be tarred immediately". It was not possible, however, to make a start with this work until 1956.

The Commission also recommended the establishment of a soils laboratory for the testing of soils, gravel and stone types for the purpose of road construction. On gravel roads they recommended one motor grader for every hundred miles on main roads. Towards the end of 1953 testing of materials for gravel roads and two years later for paved roads started at the Central Laboratory.

By Executive Committee Minute No.256 of 22.02.1956 it was approved that two construction units be equipped, including the conversion of the existing first unit, to start with the construction on the first paved roads in Namibia. The building of a double lane paved road from Windhoek firstly to Brakwater, secondly to Aris and thirdly to Kapp's Farm was to be set as a target. Additional it was resolved by Executive Committee Minute No.1156 of 17 October 1957 that one, already built gravel road in the north, i.e. the Otavi- Tsumeb road (trunk road 1/9) and another, entirely new trunk road in the south, from Keetmanshoop in a northerly direction for approximately thirty miles (trunk road 1/3), be given out under contract in order to be paved. The structure of the layerworks for these first paved roads in Namibia and typical examples highlighting the further development of structural pavements for paved roads are shown in table 7.

A proposed long term policy to pave 2.000 miles of trunk roads was accepted in principle by the Executive Committee by Resolution No.670 on 16 July 1958. It was suggested to provide the whole Namibian trunk road system with a 20 feet wide bitumen surface and the cost in those days for 2.000 miles were estimated with R 60 million [10].

Also the tempo of re-gravelling of existing gravel roads increased considerably. From the financial year 1957/58 to 1964/65 the mileages of gravel road construction increased from 188 miles to 682 miles. No detailed data for these first gravelled roads on a big scale are available. Normally it was left to relatively untrained people like " Roads Superintendents" and " Roads Foremen" to select gravel materials. In most cases these road building materials were not properly controlled during the selection and the construction/compaction process by soil mechanical means. Where no water was available dry compaction was applied. Normally a 6" (150 mm) gravel layer was applied without applying any quality and cost optimising methods. In most cases calcretes, quartzitic and mica schist materials as well as shales were used. This practice continued more or less to the present point of time.

That Namibia's unique " salt-gravel roads" came into being in the late forties happened almost by chance. Heavy trucks bringing salt blocks from the salt mines north of Swakopmund to Namibia's harbour town, Walvis Bay, used the poor tracks along the Atlantic coast. The sandy desert sections could only be crossed with great difficulties, and it was duly decided to repair the tracks with the freely available salt/clay material under supervision of the Roads Branch of the SWA Administration. No material specification for this unique gravel mixture existed at this time, but the unsaturated rejected low-salt content material from the salt mines and salt pans north of Swakopmund was placed on the road by trial and error, distributed and levelled by hand and then traffic-compacted by the same trucks which caused the damage. In many cases, during their empty return trips, these trucks were used to haul some of the salt-concentrate. The new innovative road building and maintenance method resulted in a road type which was dust-free and looked nearly as a black-top road, long time before the first bitumen surfaced roads came into being in Namibia (Verbal information supplied by Siegfried Engels, one of the oldest, still living Namibian "Padmakers" (road builder). Engels was one of the last witnesses of a memorable era of road building in Namibia when, for instance, it was normal practice to improve the dangerous crossing of the Omaruru River north of Hentiesbay by paving the riverbed with "sealskins" to get the traffic across.).

During the 1950s the newly created " Salt Maintenance Unit SMU 1" began with serious construction of a high standard salt-road from Walvis Bay in a northerly direction. In the early 1960s the 'SMU 1' reached a point just north of Cape Cross at km 140 (Mile 87, north of Swakopmund). Simultaneously the " salt-road-technique" was also used to build the first section of the trunk road 2/2 from Swakopmund in the direction of the inland towards Usakos which proved to be a successful experiment as long as the salt-gravel method was applied in the moist mist-belt region of the Atlantic coast. At the end of the 1960s a point 209 km north of Swakopmund (Mile 130) at the Ugab River mouth was reached.

Most of the trunk roads and some of the main roads are in the mean time paved roads. All the layerwork data of these paved roads are stored in an extensive databank, the " Pavement Management System", in the Central Computer System of the Ministry of Works, Transport and Communication. Generally these paved roads consist of light blacktop applications ( surface dressings) on natural gravel bases and subbases. Typical examples are shown and explained in table 7, sorted according to their ages from 1957, when the first paved road in Namibia came into being, until 1985. Most of the unpaved main roads are improved roads with gravel wearing courses and most of the district roads improved earth roads. No historical, structural layerworks data are available for unpaved roads. A generalised summary of all Namibian roads according to their pavement types is shown in table 6:

 

TABLE 6  NAMIBIA: ROADS ACCORDING TO THEIR PAVEMENT TYPES

 

|==================================================|
| DESCRIPTION DISTANCE (km)                        |
|--------------------------------------------------|
| PAVED ROADS TOTAL                       4.402,01 |
| TRUNK ROADS                             3.291,36 |
| MAIN ROADS                              1.057,97 |
| DISTRICT ROADS                             52,68 |
|--------------------------------------------------|
| UNPAVED ROADS                                    |
| GRAVEL ROADS TOTAL                        23.505 |
| TRUNK ROADS                                  749 |
| MAIN ROADS                                 7.692 |
| DISTRICT ROADS                            15.064 |
|--------------------------------------------------|
| EARTH ROADS TOTAL                         13.019 |
| TRUNK ROADS                                    - |
| MAIN ROADS                                    15 |
| DISTRICT ROADS                           12.1904 |
|--------------------------------------------------|
| GYPSUM/SALT ROADS TOTAL                      228 |
| TRUNK ROADS                                    - |
| MAIN ROADS                                    71 |
| DISTRICT ROADS                               157 |
|--------------------------------------------------|
| SANDSPOOR ROADS TOTAL                        418 |
| TRUNK ROADS                                    - |
| MAIN ROADS                                     - |
| DISTRICT ROADS                               418 |
|--------------------------------------------------|
| TOTAL 41.572 km                                  |
|==================================================|
NOTA: Departmental statistics for the period between March 1986
and September 1986 and including Walvis Bay

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