Title: Performance of Transverse Joints in Prestressed and Reinforced Concrete Airfield Pavements
Author(s): Michel Sargious
Publication: Journal Proceedings
Appears on pages(s): 359-366
Keywords: airports: concrete pavements: concrete slabs:control joints; dowels;joints (junctions); ioint sealers;prestressed concrete: reinforced concrete; runways: shrinkage;taxiways; thermal expansion.
The movements at the expansion joints of prestressed concrete pavements and at the contraction and expansion joints of dowled reinforced concrete pavements were measured every 3 hr for some taxiways of an airport during different months of the year. The widths of lanes and spacing between expansion joints were the same for both types of pavements. The results are reported for eadings taken during a 1 year period. Due to concrete shrinkage, the contraction joints of the dowled concrete pavements started to open after a few days from casting. However, it took several moths for many of these contraction joints to open for full slab thickness. At that times, these joints started to act patially as expansion joints and decreased the movements due to temperature variation at the actual expansion joints of the dowled pavements. On the other hand, the daily and seasonal movements at the expansion joints of prestressed concrete pavements were considerably larger tha the corresponding ones for the dowled concrete pavements. During the fist few months after casting, the ratio between daily slab length changes at the expansion joints in prestressed and reinforced concrete pavements having the same length between the expansion joints and subjected to the same temperature variations was about 2:1. Later on, this ratio increased rapidly, when the contration joints of the dowled pavements opened for full slab thickness and satred toabsorb a large part of the individual slab length changes, thus releasing the expansion joints from taking the full slab movement. The performance of different types of poured-in-place joint sealants, poured during various times of the day, was also checked during this study. While the sealents gave satisfactory results at the contraction and expansion joints of dowled concrete pavements, their use in prestressd concrete pavemens, even with short lengths, was not ucessful. The bond between the joint sealant and the sides of the prestressed concrete slabs, although improved by using lubricant adhesiv, was not sufficant to resist he tearing forces caused by the continious large movement of prestressed concrete pavements.