The prognosis of durability of concrete pavements made of the recycled aggregates from 80-year-old road concrete

Resumo

In the years between 1933 and 1937 at the western Polish border two sections of
highways were made of cement concrete. The first was Breslau - Liegnitz (12 December
1933-27 September 1936), the second one – Bunzlau – Sagan (21 March 1934 – 27November
1937) [Web1, Web2]. In 1995, the concrete surfaces were used to upgrade a 7-km into stretch
Golnice – Krzyżowa and a dual carriageway was built from the concrete surface (the former
A12). The authors of the paper were involved in the processing of the concrete debris and
assessed the quality of the recycled concrete. The demolition of the cement concrete surfaces
took place from 1995 to 1997, the cement debris was used to construct the lower layers of the
present A18 motorway. It is a well-known fact that recycled concrete is produced similarly to
traditional concrete. Implementation of the recycling techniques in the construction of the
motorway has been analyzed to give a clear picture of the issue. Old concrete panels with
resistance of approximately 80MPa were used in the recycling process. After breaking them
into pieces, the panels were crushed to separate fractions, which was further used to form two
kind of pavements: concrete lower layer – recycled concrete aggregate from the fraction 2/8,
8/16 and 16/32 and sand (original) 0/2 mm, upper layer all - in aggregate (original) of fraction
0/16. In 2012, the samples taken from the 80-year-old concrete and more than 15-year-old
recycled concrete, both stored in PUT laboratory, were re-examined. The physical and
mechanical characteristic of the two concrete groups were specified. The textures were
assessed by means of scanning electron microscopy.