Concrete deck rehabilitation with asphalt

Situation

In October 2011, Wundtstraße in Leipzig was renovated. The plan was to restore the existing concrete carriageway, which was in dire need of repair, by overlaying it with asphalt. Wundtstraße is the main access road from the south into the city centre of Leipzig and a main exit road towards Borna/Altenburg and Chemnitz. According to the inventory data from the City of Leipzig’s Transport and Civil Engineering Office, Wundtstraße is classified as construction class I and, in parts, construction class SV.

Solution

In accordance with the rehabilitation plan, 12 cm of the existing concrete was first milled off. The milled concrete layer was cleaned, oversized joints were filled with hot, pre-bituminised 5/8 aggregate, and open concrete joints were filled with a crack-sealing compound. To effectively delay the expected future penetration of the expansion joints into the new asphalt superstructure, the Transport and Civil Engineering Office of the City of Leipzig decided to install an asphalt reinforcement made of PVA. To this end, approximately 2.00 kg/m² of emulsion (C69BP4-OB) was first sprayed onto the milled concrete base. The asphalt reinforcement was then laid in accordance with the installation instructions. The laid asphalt insert was overlaid with an 8 cm binder course (AC 16 BS) and a 4 cm asphalt surface course (SMA 11 S).

Advantages

PVA exhibits excellent resistance to alkaline environments. For this reason, it is particularly suitable for the rehabilitation of concrete surfaces with asphalt. The use of asphalt reinforcement has proven effective in the rehabilitation of concrete carriageways for the long-term prevention of reflective cracking. The associated savings lead to a significant reduction in maintenance costs for asphalt carriageways.