At least Tk 100 billion will be needed to transform the flexibly built road network into a durable one as per the desire of the prime minister, according to estimates done by experts.
The concrete roads have better life-span and require lesser maintenance compared to those of the bituminous roads, engineers said.
The roads and highways are usually cast in concrete since those take lots of wear and tear, particularly during rains and floods.
Experts, however, while suggesting transformation of the bituminous roads into concrete ones warn of the possibility of misuse of public money. They maintain that necessary surveys and studies are required before starting any major nationwide transformation work. Â
They argue that after the 80s, the country's entire 8,000-kilometre concrete road network was gradually reconstructed into flexible one, using bitumen. Funds worth billions of taka have been spent since then.
Sources said agencies, including Roads and Highways Department (RHD), Local Government Engineering Department (LGED) and city corporations, pourshavas, responsible for building national, regional, zila, upazila and city roads across the country -- have already started implementing the road-conversion projects.
On an average, 10-15 per cent of the roads belonging to these agencies are now being built in 'rigid' method that necessitates the use of concrete. They, however, admit that there is no guideline or standard for the agencies in this respect. Engineers and contractors concerned construct concrete roads the way they feel like.
A study paper prepared by Santosh Kumar Roy, executive engineer of RHD, showed that the construction a kilometre of standard 'rigid' pavement costs over Tk 60 million, slightly higher than that of 'flexible' road built with bitumen.
He, however, estimated that nearly Tk 55 million could be saved from per-km rigid pavement since the same, if constructed properly, needs far less maintenance work for a period of over 20 years.
In the current fiscal year, the division concerned placed demand for Tk 70 billion for repairing and maintenance of 200-km vulnerable bituminous roads. But the RHD got around Tk 14 billion.
Mr Santosh, also project manager of the Dhaka-Chittagong four-lane road project, told the FE that the demand for maintenance has increased fivefold in the last four years as it has become difficult to keep the bituminous road durable due to water-logging.
According to the latest official data, the allocation of funds for maintenance of national and regional highways has increased from Tk 5.6 billion to Tk 14 billion in last four years.
"In the country's context, we have no option but to go for rigid pavement. At least the national highways which are planned to be turned into four lanes should get priority," said Professor Shamsul Haque of Bangladesh University of Engineering and Technology (BUET).
In his view, the rigid pavement is suitable for highways where frequent digging would not be necessary for providing utility services.
As the government has planned to upgrade all the two-lane national highways to four-lane ones in next few years, the RHD itself would need at least Tk 200 billion to build extra two lanes with rigid pavement.
Of the ongoing four-lane projects, eight kms have been constructed with rigid pavement in bazar areas on Dhaka-Chittagong highway.
Talking to the engineers and officials of different agencies, this correspondent found that there is no consistency in constructing rigid pavement due to absence of guidelines. Â
The LGED prefers constructing rigid road in areas prone to flash -flood and it has already built over 2,554-km road with concrete -- both CC and RCC. But some city corporations do concrete finishing over the bituminous roads, lanes and by-lanes as they face difficulties in taking the bitumen-carrying heavy plant there.
The RHD has now 21,589-km road network, including 3,619-km national highways. The LGED has around 70,000-km flexible roads and only 2,554-km rigid roads.
Dr Shamsul Haque, however, admits that any mistake committed in maintaining the water-cement ratio causes damage to the rigid road because once a rigid road develop potholes it cannot be restored without total recasting.
So rigid pavement is not desirable in city or urban areas, he pointed out.
An engineer working with a government agency said it would not be wise for the government to make a U-turn on its decision. If it is done, the country would have to spend again billions of taka.
Officials said fresh directive from the Prime Minister came last year, in view of the country's reality, to recover bazar areas where water logging situation is uncontrollable. Despite having axle-control stations, the plying of overloaded vehicles could not be restricted in these years, making it necessary for transformation.
Rigid pavement is being recommended for its less vulnerability to water and capacity of taking load.
But the critics said today or tomorrow, the government would have to restore or reconstruct the drainage system even to save the rigid pavement.
They said water may cause severe damage to rigid pavement if it enters the sub-base, which is apparent for lack of drainage system and frequent floods in absence of dredging.
Dr Shamsul Haque said though rigid pavement has to ensure less compliance in comparison with flexible pavement, efficiency of engineers and contractors in all three stages is a must to get maximum benefit from the concrete road.
An engineer of the Public Works Department said due to lack of efficiency in ensuring compliance, flexible pavement or bituminous roads are found unfit for traffic within a year of construction.
"It is possible to keep the road network safe and smooth by ensuring efficiency. Without recovering roadside land, restoring drainage system or axle-load control on roads and highways, it won't be logical to shift road construction approach," the engineer said.
Once the RHD has a laboratory to test construction materials and suggest suitable way to construct roads but its performance cannot guide the engineers.
Santosh Kumar in his paper recommends forming a high-powered technical committee to examine the condition of the existing rigid pavement roads and collect and evaluate the design data to verify those with the international standards to set a universal guideline for the authorities concerned.
   smunima@yahoo.com
Casting in concrete to help extend life of highways
Munima Sultana | Published: February 16, 2015 00:00:00 | Updated: November 30, 2024 06:01:00
Share if you like