You have one of the largest opportunities of your career within reach but you lack the tools to take advantage. Would you throw up your hands and miss out because you aren’t prepared? Or would you take a leap of faith and get the best tool for the job even if you aren’t sure how it works. Udomsak Chiang Mai Company of Chiang Mai, Thailand has plenty of paving experience using fixed forms and a roller screed. Khun Pisit Trakarnsiri, Managing Director, had a chance to pave the large four-lane, 5.6-mile job near Korat. However, the deadlines on the job were too tight for forms and a screed. To seize the opportunity, a slipform paver would be required. After considering all the options, Khun purchased a Power Curber 7700 Multipurpose Slipform Machine because its advanced control system is easy to operate and its designed to excel at standard and offset paving.

The job conditions were challenging for a slipform paving machine. Historically, Udomsak prepares their paving jobs with a compacted subgrade and a ten-centimeter (four-inch) subbase of low-compaction sand. While that works well when using forms and a screed, the heavy, four-track 7700 required additional compaction. Thananut Trakan, Project Engineer, describes the International Roughness Index (IRI) specifications saying that “the road authority required less than 2.5, but we achieved an average of 1.9.” The road used continuous reinforcement, so placing the concrete was a concern.

Using the cross-slope function, the 7700 was able to save setup time by running on a single stringline and allowed the mixer trucks to pour from the opposite side. The single stringline was remarkable considering the job’s frequent transitions from a two-percent to over seven-percent super elevation. The twenty-eight-centimeter (eleven-inch) thick lanes were slipformed in two passes at 3.5 meters (11.5′) wide with a third pass of 2.5 meter (eight-foot) wide offset paving for the left shoulder, and a fourth pass of 1.5 meter (five-foot) wide offset paving for the right shoulder. To join the slabs together, a side tie-bar-inserter was used to add tie-bars on sixty-centimeter (two-foot) centers.

While the versatile 7700 overcame the site challenges, Udomsak succeeded with thorough training and support. Power Curbers’ commitment was absolute, with multiple support technicians instructing on site. Italthai Industrial Co Ltd, Power Curbers’ Thailand dealer was a valuable asset as well. They were essential in coordinating the mix design, concrete supply, and ensuring continuous support. On their best days, Udomsak managed over 730 linear meters (2400 linear feet) with the 7700 compared to the 215 linear meters (700 linear feet) with their forms and screed. Khun compared that “the cost of labor broke down to sixty to seventy baht ($ 1.95 – 2.27) per square meter, but with the 7700 it is reduced to twenty-five baht ($ 0.81) per square meter. The leap of faith is working out for Udomsak. Khun shared his thoughts on the purchase, “I see that it is very effective. I use it and it delivers. We can see the cost savings and I can trust in the quality of work.”