Retarder Application to Longitudinal Roller Compacted Concrete Pavement Joints

In the case of roller-compacted concrete pavements (RCCP) in spacious site like yard, harbor and so on, socalled fresh joint technique at longitudinal joints is widely used in order to achieve high load-transfer efficiency. However traditional fresh joint technique allowed the limited length of placing, because delay between the fresh preceding lane and new lane is restricted to within 90 minutes in Japan. One of the solution of it might be using the concrete with retarder mixed in mixing plants, but it is not economical because retarder is used in the full width of the preceding lane. Therefore the splaying and mixing of retarder at only longitudinal joints at the job site was developed to make the fresh joint technique the economical and rational solution. This paper covers developing process through the laboratory experiments and field tests, the results of loading test at the longitudinal joints made by this technique, and the examples of the application of this technique to RCCP jobs.