The rising trend of setting fire on roads during demonstrations is worrying authorities due to the cost of repairs to the damaged roads.

Officials at Blantyre City Council (BCC), which is one of the cities affected by demonstration road fires, say the council is grappling to find money to maintain roads that have since been destroyed in the course of residents exercising their right to freedom of expression.

Since the July 20, 2011 nationwide demonstrations, roads in the city of Blantyre have come under increased attack during a number of protests by disgruntled groups who usually set alight old car tyres on the roads.

BCC Director of Engineering Francis Namonjeza told The Sunday Times in an emailed response that the practice is causing a lot of damage to road infrastructure in the city.

“When a road surface is subjected to excessive heat, material properties of the binder component of the wearing course are altered resulting in disintegration. This leads to emergence of potholes,” he said.

Namonjeza said the potholes may not appear immediately and their emergence will depend on traffic load and frequency which varies from spot to spot.

He, however, said the council is finding it difficult to find a way how to mitigate the effects of the damage which he said is expensive to maintain.

“In most cases, such things occur during civil unrest as such that is difficult to control. Current market rates for pothole repair are at K12, 000.00 per square metre,” he said.

Both BCC and National Roads Authority (NRA) confirmed that they have not carried out an assessment of road defects as a result of road surface being exposed to excessive heat emanating from burning of tyres on the roads.