Concrete paving: Potential game changer in road construction

Ready-mix concrete is on a truck. An excavator carries and pours it onto the surface of an under-construction road. Then an automatic concrete-paving machine joins in and does the rest.

This German-made slip-form paver machine levels the surface seamlessly, giving it a complete look of a paved road.

This correspondent saw the process in Dhaperhat area of Gaibandha's Saduallapur upazila on Monday as the authorities of an RHD project is using the state-of-the-art technology for the first time in the country to construct concrete pavement.

The authorities of SASEC Road Connectivity Project-2, under which 190km highway is being expanded into four-lane from Elenga of Tangail to Rangpur, are using two such paver machines for constructing 60km concrete road there. The highway has also service lanes.

Construction of such a large portion of highway with concrete pavement is also new in the country, where flexible pavement using bitumen is common.

The project authorities said taking the climate of Bangladesh into consideration where rainy reason is relatively longer, concrete pavement is more durable and cost effective and the ride quality will improve due touse of paver machines.

Transport expert Prof Shamsul Hoque, who led a Buet team for the design works ofjointless concrete pavement, said the road authorities have to go for concrete pavement gradually for sustainable development.

He said as overloaded vehicles run onthe Dhaka-Tangail-Rangpur highway, they recommended jointless  reinforced concrete pavement instead of bituminous pavement. Besides, considering climate issues, the prime minister on several occasions directed the authorities concerned to go for concrete pavement to reduce maintenance cost, he added.

The authorities have to consider life cycle costs, including construction and maintenance costs, before going to implement a project. Considering the aspect, concrete pavement is more viable, he told The Daily Star yesterday.

The Roads and Highways Department is implementing the project at a cost of Tk 16,662.38 crore with loan from Asian Development Bank. The project deadline is December 2024.

In Bangladesh, flexible pavement is being constructed on almost all roads. But lately, concrete pavement or rigid pavement is being built on some parts of highways, especially in market and toll plaza areas and the places prone to waterlogging.

Santosh Kumar Roy, additional project director, said they decided to construct concrete pavement keeping various benefits in mind.

He said Bangladesh experiences rainfall for five to six monthsa year while temperature relatively remains high during the summer. But bitumen is vulnerable to water and heat, Santosh said, adding that overloaded vehiclescause serious damage to bituminous pavement.

He said although thedesign life span, the life expectancy of a structure, for bituminous road is 10 to 15 years, it has to be repaired every two-three year after the construction due to waterlogging, plying of overloaded vehicles and some other reasons, which need a huge amount of money.

On the other hand, the design life span of concrete pavement is 20 to 25 years and its maintenance cost is very minimal, the project official told The Daily Star.

Replying to a question, Santosh said the construction cost of concrete pavement is 10 to 15 percent higher than that of bituminous pavement, but the total life cycle cost of concrete pavement is 50 percent lower than the bituminous pavement due to nominal maintenance cost.

Besides, the high price of bitumen is now a major challenge for project implementation, he said.

He added that except stone, materials used for concrete pavement are available in the country and that's why concrete pavement is helpful in context of the current US dollar crisis.

Considering all these issues, Santosh said they have decided to build concrete pavement and out of 81km road from Bogura's Mokamtola to Rangpur, they will construct some 60km concrete pavement. Besides, around 20km of concrete pavement would be built in market areas on the other part of the highway, he added.

This correspondent found that construction of concrete pavement in a major portion has already been completed.

Santosh said construction of concrete pavement manually causes roughness on the surface, which impacts on the ride quality. But their Chinese contractor is now using automatic concrete-paving machines, which ensure smooth surface, he added.

He said they are building two types of concrete pavement -- continuous reinforced concrete pavement and joint reinforced concrete pavement.

Asked if concrete pavement is comparatively cost-effective and durable, then why other road project authorities are not using this construction method, Project Director Waliur Rahman said, "It is difficult to change a long-time practice. We hope other project authorities concerned will build concrete pavementsafter knowing about our 'positive experience'."

RHD sources said officials of the road transport and bridges ministry and Implementation, Monitoring and Evaluation Division visited the road.

They recommended carrying out an inspection by the third party as this is something new in Bangladesh.