Recently, a call was made to the Federal Government to consider FactFile switching from asphalt to concrete roads as a measure towards solving the problem of road durability in the country. Nwakaego Ohaegbulam looks at the pros and cons of concrete road
Overtime, the President of Dangote Group of companies, Alhaji Aliko Dangote, has made suggestions to the Federal Government on how to solve the problem of road durability which has made mockery of efforts and massive funding of roads by past administrations. His suggestion has caught the attention of stakeholders to become a key issue raised at the on-going 21st Summit of the Nigeria Economic Summit Group.
This formed the fulcrum of the speech delivered by the Executive Director Stakeholders Relations and Corporate Communications, Eng Ahmed Mansur, Dangote Group at the summit. He said that for a country like Nigeria, concrete roads made more economic sense as the use of asphalt had left the roads in deplorable conditions. Asphalt he said, was no longer in vogue in developed climes. The construction of concrete road was faster while boasting of a durability of half a century.
While asserting that concrete roads were 20 per cent cheaper to build, Engr. Ahmed explained that compared to asphalt, the material needed for the construction of concrete roads which is cement, was readily available unlike the asphalt which had to be imported and maintained that concrete road is a choice which the country must make.
In his earlier contribution to the matter, the Chairman, Dangote Group, Aliko Dangote had recently in Lagos, pleaded with the Federal Government to consider the use of concrete roads in the country. According to him, concrete roads will be to the benefit of Nigerians because apart from being very cheap, concrete roads are more durable with a near zero maintenance cost. “We are pushing for Nigeria to do a concrete road. It is cheaper to do a concrete road that will last 50 years than to do a bitumen road. It will also eliminate corruption because if you go and build a bitumen road, it will have to be adequately maintained unlike a concrete road that is very durable, “he said.
Road surface, Wikipedia said is the durable surface material laid down on an area intended to sustain vehicular or foot traffic. In times past, gravel surfaces, cobblestone and granite setts were extensively used these were later replaced by asphalt or concrete laid on a compacted base course. Experts have identified three major road types to include asphalt, concrete and earth or earthen roads (graded roads in the lay mans terms). While these roads all sustain vehicular and foot traffic, the earth road is the least durable of them all.
Asphalt on the other hand, has been widely used since the 1920’s mainly because it was easier to construct roads made of aggregates comprising stone, sand, gravel and hot liquid asphalt evenly spread on the earth surface. Such roads usually glittered while appearing to be durable unfortunately; most of them do not stand the test of time especially when subjected to the tires of heavy duty trucks.
In a paper presented to the Department for International Development, DFID, titled ‘Concrete Roads in Developing Countries’ J.D Parry observed that in the past, bituminous surfaced roads had been cheaper to build than concrete ones, but the rapid rise in oil prices during the last decade greatly reduced the construction cost differential. “Additionally, the normal maintenance operations on the two types of road are different in character and experience from the industrialized counties suggests that concrete roads require substantially less maintenance than bituminous surface roads. In view of the difficulty that many developing countries are experiencing in maintaining their road networks, the prospect of roads that are comparatively maintenance free is very attractive.
” According to a US based construction company, Bright Hub Engineering, concrete roads have a long service life of forty years whereas asphalt roads may or not last for ten years. This is coupled with the fact that during the service life, concrete roads unlike asphalt do not require frequent repair or patch work. Also vehicles that run on concrete roads consume 15-20 percent less fuel than they did while on asphalt roads. This the company said was because a concrete road does not get deflected under the wheels of loaded trucks. Unlike asphalt roads, concrete roads do not get damaged by the leaking oils from the vehicles or by the extreme weather conditions like excess rain of extreme heat.
Furthermore, asphalt derived from imported petroleum, produces lots of highly polluting gases at the point of being melted for paving thus making it expensive when compared to concrete that is produced from abundantly available limestone. Contrary to widely held belief that concrete is not recyclable, construction experts say that concrete is 100 percent recyclable because the components or slabs taken out during repairs can actually be broken down and reused for other construction purposes.
A 2007 study conducted in the United States proved concrete is light and naturally reflective unlike asphalt which is black and absorbs more heat. This the study said means that the light nature of the concrete helps keep the areas around the pavement cooler which translates to a reduction in the consumption of electricity for air conditioning.
These advantages notwithstanding, concrete roads have its down sides too. For instance should there be any break on a concrete road, the entire slab would be replaced secondly, during the wet season, vehicles tend to slip or slide on concrete roads.
Evidently, the advantages of concrete roads over asphalt outweigh its disadvantages by far, could this be the reason for the clamor. As Parry put it “from the evidence available, concrete should be considered as an alternative form of construction, particularly in those – developing countries with indigenous cement manufacturing capability. Some countries are net importers of cement and some produce only sufficient supplies for their building trade, but world-wide there is surplus capacity, particularly in south-east Asia.’ Even where the initial cost of construction is higher than for a comparable bituminous surfaced road, the reduced maintenance requirement over the design life and may make this type of construction more economic in the long term. This should be considered particularly in those countries experiencing difficulties maintaining their road network to an economic standard.”