Effectiveness of Breaking and Seating of Reinforced PCC Pavements Before Overlay

摘要

Four sections, each a mile long, were broken and seated prior to constructing anasphaltic concrete surface layer. Five control sections were constructed, adjacent to the Breaking and Seating (B/S) sections. The test sections were all Jointed Reinforced Concrete Pavements and carried a large amount of traffic. The original pavements selected in the study were fairly uniform with respect to their structural and surface conditions. The thickness of the concrete layer was the same (22.5 cm or 9 in.) throughout and the subbase and subgrade exhibited very little variation. The AC overlay thickness was the same for the B/S and the control sections (16.5 cm (6.5 in) in one area and 21.6 cm (8.5 in) in the other area). Two types of pavement breakers were used in this study, namely guillotine and pile hammer. The goal was to break the slabs into segments of 045 m x 0.45 m (18 in. x 18 in.). The extent of breaking was closely monitored. The performance of the test sections was monitored for a period of about two years. Performance evaluation was made based on (1) structural response and (2) reflection cracking. The results of this study confirm the previous findings regarding (1) the effectiveness of breaking and seating in delaying reflection cracks, and (2) reduction in structural capacity, increase of surface deflection and loss of flexural strength. It is observed that type of breaking equipment and extent of breaking are the most important factors that govern the early behavior of break and seat sections.