Hot mix asphalt - the "paving under sub-zero temperatures" experience

Rijkswaterstaat’s recent “Asfalteren onder het vriespunt (Paving under sub-zero temperatures)” provided an interesting research opportunity for the Asphalt Paving Research and Innovation (ASPARi) unit. The participating contractors both chose to adopt ASPARi’s Process Quality improvement (PQi) methodology to monitor their paving and compaction work. This presented a number of challenges for the construction teams and presented an opportunity to compare the operational strategies employed by the two contractors. The conditions at the time of construction were the same for both contractors; and the goals and objectives were the same given RWS’s requirements. It would therefore be interesting to see whether the approaches to construction would be the same. The results show that whilst the contractors used similar equipment and introduced several innovations to counter the effect of the cold conditions, the adopted operational strategies and approaches are different. From a research perspective, the main challenge was being able to deal adequately with monitoring two construction teams simultaneously and being able to organise sufficient resources and personnel within the 48-hour window after the “Frost-Go” notice was given.