ABSTRACT
In this article the short-term aging of bituminous sealing compounds for bridge deck joints is described with respect to both laboratory tests and field performance. Four different products containing elastomers as a modifying agent were applied under controlled conditions to four test fields in Switzerland. Constructions of the plug joints consisted of three layers of sealants, which were placed successively and reinforced with aggregates. From each layer a sample was collected to study the aging during construction.
In addition, different laboratory aging methods were applied to the bituminous joint sealing compounds in the state of delivery: Rotating flask at 165°C (DIN 52016 [1]) and 180°C, rolling thin film oven test (RTFOT) at 180°C and storage in the oven at 70°C for 14 days (SN 671’904 [2]) and 80°C for 7 days.
Laboratory aged and non-aged samples, as well as samples from the field were characterised by penetration, ring and ball softening point and thermogravimetric analysis. The state of polymer in the sealants was investigated using gel permeation chromatography (GPC). The short-term aging methods were compared using the results from the different characterising methods described above. The states of the joint sealants from the field objects were compared and correlated.
The change of physical parameters during installation of the bridge desk expansion joints corresponds approximately to the change found for laboratory thermal oxidative aged samples. According to GPC the degree of polymer degradation in the polymer bitumen joint sealants during installation corresponds approximately to thermal aged laboratory samples.
