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Planning Minister ANH Mustafa Kamal has recently raised a serious question of biasness towards the construction of bituminous (flexible) roads despite their poor performance. During a September 22 seminar organised by the Roads and Highways Department (RHD) in Dhaka, he asked for the construction of concrete (rigid) roads with expectation of no maintenance requirements even after 10 years of construction.
The question is: why is the RHD not opting for concrete roads? Is it for the scope of misappropriation of repair funds that come with the maintenance-hungry bituminous roads? Or, are there important technical and institutional issues that discourage RHD leadership to go for concrete roads?
Bangladesh is a country with heavy rainfall and recurring floods. Hydrophobic bituminous material easily strips off stone aggregates and eventually leads to road failure through the development of numerous potholes. A concrete road, on the other hand, performs better during the rain and flooding events because of strong bonding strength and spreading load distribution. It usually needs higher construction cost, but gives return over the design life due to much less maintenance needs and relatively longer life.
Road construction in Bangladesh is very expensive. General perception is that gross corruption in the sector is responsible for this. However, this is simplification of the problem which frustrates proper development of road projects in most cases. It hinders the development of local road science and ultimately leads to the delivery of weaker roads. In fact, the need for land acquisition; construction of high embankment, flood protection works and numerous bridges and culverts; import of road materials and equipment from abroad; weak procurement process; poor construction methodology; design reviews during construction because of changing requirements; construction delays due to fund shortage; natural calamities; political unrest; and skill shortage all have made road projects in the country significantly different from most other countries with consequent impact on project costs.
The scope for cost reduction in future is limited for the prevalent conditions. So, the cost of switching to concrete roads from bituminous roads would be minimal in the context of total project cost. Unfortunately, the pressure of cost rationalisation often leads to trimming the pavement with inadequate thicknesses and inferior material types for different layers as the scope of reduction in other components is difficult to find. So, the blame on poor performance of the conventional bituminous roads rather lies with the design decisions - not the pavement type itself.
Pavement design has advanced significantly in other parts of the world. Normal bitumen has now been replaced by polymerised bitumen that performs better under extreme stress conditions. Conventional bituminous surfacing has now been replaced by high-strength surfacing such as Stone Mastic Asphalt (Germany), Hot Rolled Asphalt (UK) and EME2 (France) surfacing. Unbound materials have now been replaced by cementitious, bitumen-treated or foam bitumen materials for road foundation. Inclusion of drainage layer and extensive surface drainage network are now widely in vogue for managing road waters, which should be the vital consideration for designing road pavements in Bangladesh.
Bangladesh needs to adopt the advanced pavement technology for building better roads. Otherwise, only moving to concrete roads would not ensure good roads. Concrete technology is rather complex from construction point of view. Any damage needing rectification is difficult to make and may disrupt traffic for a long time. Rehabilitation of concrete pavement after the end of design life is highly critical. Therefore, construction of concrete road needs the use of best available technology, strict quality control and continuous service life condition assessment and maintenance regime for the best possible longevity. This seems very difficult for Bangladesh to achieve as the RHD and the local contractors do not have any experience or expertise in the field.
So, how to overcome the impasse? Should the RHD be blamed for its failure to deliver concrete roads? As an implementing agency, RHD can be credited to have developed a 21,000-kilometre road network across the country with numerous bridges that allows ferry-free road transport from Teknaf to Tetulia. The RHD engineers and employees have been sacrificing their Eid holidays since 2011 for the countrymen to have Eid days with their near and dear ones. The failure to achieve advanced technology is thus not intentional, rather it could be institutional.
RHD has a traditional organogram. It doesn't have any specialised branch for developing or adopting new technologies, standard and specification. Most of the road agencies in the developed world have a big Engineering and Technology Branch that serves this very purpose. Highly educated engineers and specialists are appointed with higher positions, salaries and benefits for the services of importance. The policymakers of the country should give serious consideration to the matter.
To facilitate road research, many countries have separate organisations. The Transport Research Laboratory (UK), Australian Road Research Board (Australia), and Central Road Research Institute (India) are some of the examples. These research organisations with support from the road agencies' specialised branches provide the services of technology advancement. It involves significant tasks of identifying needs, finding potential solutions, conducting adoption study, laboratory works and a series of trial constructions for standards and specifications development, transferring knowledge to the industry through hands-on training, and follow-up evaluation and reviews.
It would not be advisable for Bangladesh to hazard constructing complex concrete roads without accomplishing the above reforms. It is not possible to build quality bituminous roads without improving the technology for local conditions?
Road engineering is mainly based on empirical science. Construction and management of an affordable good road network requires delicate considerations to the locally available road materials, local environment, social and economic conditions, traffic levels, traffic type, freight payloads, driving culture and many other aspects. So, adaptation of best practices from other countries is important before implementation of new technologies.
To explore all the available options and to allow different industries to grow, many countries promote both bituminous and concrete roads in a balanced way. There are composite pavement types as well - a blend of cementitious and bituminous layers - that serve the local conditions best. Bangladesh should progress in the same way?
Foreign consultants have been involved in all the major road projects since the country's independence. However, their lack of knowledge about local conditions and expertise failed them to deliver the designs Bangladesh needs. So, the road institutions should urgently be improved and in-house expertise developed. Otherwise, making of concrete roads or advanced bituminous roads are unlikely to bring in any difference.
The government is now implementing a number of big road projects. The perceived technical shortcomings indicate a significantly high level of maintenance and rehabilitation needs of the roads in near future. It will not only be a big financial burden on the nation, but also will hinder expected economic progress.
Finally, when policymakers like the Planning Minister expect RHD to deliver concrete roads, the department should be empowered to take major technical decisions and held accountable for their decisions.
Dr. Shafiq Alam, FIEAust CPEng IntPE (Aus), is a road infrastructure specialist working in Brisbane, Australia.