When the authorities of the Czech Republic town Brandýs nad Labem-Stará Boleslav, 25 kilometres to the southwest of Prague, decided to repair its roads, the works were conditional on two factors.
First, the roads had to remain open during the works. There were no other roads to handle diverted traffic. Second, the repairs had to be completed in five days, so normal traffic flows could resume.
Mladá Boleslav-based firm USK was commissioned to carry out the maintenance. The firm decided to employ cold planing and paving to repair the 4.2 kilometre-long, six metre-wide road.
In order to carry out the repairs on the still-open roads, the firm needed a paver capable of working within a width of three metres. It also had to lay down 800 tons of aspalt per day in order to complete the job within the tight timeframe. Accordingly, the firm chose the Caterpillar AP555E Asphalt Paver.
The paver was equipped with the Mobil-Trac system, which the manufacturer says keeps a strong grip on the surface to provide manoeuvrability and speed. The crews worked at a rate of eight metres of road per minute.
The paver worked for a half day in a single direction, then returned to that day’s starting point and laid down the second half of the road with a longitudinal joint. The time taken to return to the starting point is lost, especially since many comparable machines travel at around four kilometres per hour when not paving. The AP555E paver was able to travel up to four times that speed.
To complete the project running on time, USK also had to ensure there was a constant supply of asphalt. The asphalt plant was about 40 kilometres away and a round trip took around 90 minutes to two hours. Accordingly, the firm employed six haul trucks, each with a capacity of 30 tons, to make at least four runs a day.
There was also an array of spreader augers and conveyors fitted with four independent sensors to ensure the proper amount of asphalt was delivered ahead of the paver. The conveyors were also electrically heated to keep the mix at a temperature of 145 degrees Celsius.
A 12-ton Caterpillar CD534B vibration roller followed the paver to compact the asphalt.
The firm says the entire job was completed on time and surface smoothness and quality goals were met.