Bangladesh’s high temperature besides seasonal floods led to road surface damage and bitumen corruption in many regions.
Road surfaces in several districts have melted due to what experts say is the use of bitumen that cannot resist such extreme heat.
Prof Hadiuzzaman, Roads and Highways Department Senior Engineer, says that in recent years, the authorities have been using bitumen grade 60/70 which is not performance-based and starts to soften at around 60C. even some contractors have used 80/100 bitumen, mostly imported, which is much more vulnerable to heat waves.
Furthermore, many other Bengali researchers have the same while they also have doubts about the quality of bitumen used on roads.
Following several early bitumen damages in roads, RHD (Roads and Highways Department) surveyed 18 roads and concluded to diagnose the problem of “undulation” which is made through using low-quality or impure bitumen and also construction deficiency.
Based on the Daily Sun report, Bangladesh demands “five lakh metric tons of bitumen annually” of which 70k tons were supplied domestically and “the rest is imported from Middle East countries”.
While exposure to high heat, reduces bitumen’s resilience, performance-grade bitumen would be a better choice for such a climate since the addition of polymer in bitumen can result in a higher melting point.
Hence the RHD has started using polymer-modified bitumen to repair the Dhaka-Chattogram highway and widen the Dhaka-Sylhet highway, as said its Chief Engineer Moinul. The cost of polymer-modified bitumen is around 15/20 percent higher than the 60/70 grade bitumen.
India, Bahrain and the United Arab Emirates are among the top 3 overseas suppliers of Bangladesh bitumen. Iran is also the other bitumen exporter who recently boosted its activity.
