Performance of micro surfacing on expressway

Micro surfacing is developed from slurry seal technique. It is a mixture of polymer modified bitumen emulsion with 9.5 mm chipping, quarry dust, cement, additive and water. The emulsion used in micro surfacing is CQS-1h and added with natural latex as its polymer modifier. This study was carried out to evaluate the performance of micro surfacing applied on expressway. In 2008, a number of preventive maintenance projects in North South Expressway used micro surfacing especially in the northern region. This study involved particular sections of expressways located at km 58.60 to km 59.60 south bound and km 84.60 to km 85.60 south bound from Bukit Kayu Hitam. The construction was completed on 7th January 2009. The performance of micro surfacing in this specific expressway sections was monitored for one year. The Portable Pendulum Tester was used to evaluate skid resistance performance while the texture depth of micro surfacing was measured using Sand Patch Test. The surface irregularities data was collected using a 3 m rolling straight edge while the rutting measurement was based on 3 m static straight edge. The measurement was carried out after 4, 6, 9 and 12 months period of operations starting from April 2009 to January 2010. The result shows that the skid resistance, texture depth, surface irregularities and rut depth for micro surfacing comply with the specification requirements after one year of operation. The pendulum test value obtained is greater than 46 with a texture depth of 0.50 mm. The average number of surface irregularities is below 4.0 mm while the rut depth average value is less than 5.0 m