Roads infrastructure: Composite pavement tops consideration on economic benefits
For its economic benefits, providers of roads infrastructure have been advised to consider composite pavement structure which is an overlay of asphalt on concrete road. The asphalt overlay may have been placed as the final stage of initial construction, or as part of rehabilitation or safety treatment.
For a developing nation, especially Nigeria where maintenance budget is always low or sometimes zero, this structure is more sustainable and desirable as it combines the advantages of concrete for high load carrying capacity and asphalt for safety.
Isa Usman Emoabino, chairman, Nigerian Institution of Highway and Transportation Engineers (NIHTE ), who gave these hints as guest speaker at the 20th annual Construction and Engineering Digest (CED) Forum/Award at the weekend, noted however, that composite pavement behaviour under traffic loading was essentially the same as rigid pavement.
The CED Forum-Award of Excellence and the Construct Skills Conversation, according to Kenneth Odusola-Stevenson, national coordinator, CED Forum Award and Publisher, CED Magazine, celebrate the achievements of companies and individuals with the mindset and objective of growth, development and excellence.
These were of utmost consideration in selecting the winners of this year’s award which included Iro-Vester Engineering Limited, Alfa Centuari Pumps Llimited, Automated Geotechnics Limited, Bow Dynamics Systems Limited, Global Sterling Products Limited, Natony Limited, Tegas Engineering Company Limited, Funmi Akingbagbohun, Adewale Ikotun Sam Nwosu, and Ogbonnaya Onu,the minister of science and technology.
Odusola-Stevenson noted that the CED Forum Award, established in partnership with the Federal Ministry of Works and organized by Century 21 Systems Communication Limited, remained the leading platform for the built environment, disclosing that the platform was powered by CED Magazine, the pioneer development journal for professionals in the construction, engineering, oil and gas and allied sectors.
Speaking on the theme, ‘Concrete Road in Nigeria: Durability, Acceptability and the Economic Benefit to a Developing Nation’ Emoabino noted that the alarming rate of deterioration of Nigerian roads infrastructure, despite the enormous amount of budgetary allocations, suggested strongly that the road sector was in dire need of attention, reforms, and alternatives.
He highlighted the strengths and weaknesses of other road pavements, pointing out that asphalt was still less costly compared to concrete and “it takes less time to build an asphalt road than a concrete road; asphalt dries faster as freshly laid asphalt can carry load immediately”.
“Asphalt is a recyclable material; it can be used again and again by melting it. Repairing just a part of the asphalt road is easily possible. Asphalt roads can even be relayed over the old layer, and provides better traction and skid resistance for vehicles. Asphalt tends to help keep roads free from ice and snow”, he said.
Asphalt road pavements are however not without their challenges as they are prone to damage by heavy rain and other extreme weather conditions; they need frequent repairs; excess axle load causes deflection and deformation on the road while melting asphalt produces lots of harmful greenhouse gases and is a costly petroleum product.
Emoabino also highlighted the two types of concrete pavements commonly used which, he said, were continuously reinforced concreted pavement used as deck on piles, bridges, ports, airports runways and also jointed concrete pavement used at petrol stations.
The advantages of this type road pavement is its durability and safety; It is less prone to wear and tear; has low maintenance requirements and long-term performance, about 40 years, depending however on proper pavement design, materials selection, good construction practices.
In spite these benefits, concrete pavements also have their drawbacks including initial cost of construction which is generally higher compared to asphalt paving. In the event of concrete road breaks, the whole concrete slab needs to be replaced leading to higher costs, and in rainy season, vehicles tend to slip or slide on concrete road due to rain and so could be prone to more accidents.
CHUKA UROKO