It often is impossible in the construction industry to adhere to cost estimates, as too many unknown factors may complicate the building projects and make them end up much more expensive than expected. However, the opposite can also happen as proved Altmarkbau, a German building contractor. Instead of using Roller Compacted Concrete as a construction material the company chose PCC, supplied first-class quality and managed to even cut cost.

Convincing the client of PCC’s advantages
In the first instance it was a challenge to Altmarkbau, a subsidiary of German contractor Matthäi Bauunternehmen GmbH & Co. KG. They had been invited to bid for a road building contract on the premises of a cellulose factory at Stendal, Germany, roads which after completion should be used by heavy lorries transporting timber. Although the invitation to tender had specified Roller Compacted Concrete as a construction material, Altmarkbau preferred Paver Compacted Concrete (PCC).

Point load of 200 tonnes
At first the client, a Swiss investment group, had to be con-vinced of PCC’s advantages. In order to do so, Altmarkbau built a test section with a layer thickness of 26cm for which a density of 98% was achieved. This was absolutely convincing and the client’s OK was given for PCC paving. The roads on the 60,000m2 of factory grounds have to carry a point load of more than 200 tonnes, which is roughly double the load calculated for German motorways. Altmarkbau combined their VÖGELE SUPER 1900 paver with the SB 250 B Fixed-Width Concrete Screed in TVP2 version for high compaction. Over many years VÖGELE have gathered knowledge and know-how in PCC paving. In order to suit concrete paving, the screed normally used for asphalt comes with several modifications. The depth of the tamper bar, for instance, is 58mm instead of 43mm and the bevel of the edge is smaller (30° instead of 45°), which makes concrete compaction much more effective.

The Altmarkbau team paved the 7.5m wide roads at a relatively low speed of 0.8m/min. and a density of 98% was achieved alone by the High Compaction Screed. No need for extra compaction by rolling.

PCC beats Roller Compacted Concrete
When all cost factors are considered, paving Roller Compacted Concrete (RCC) calls for a much higher expenditure of labour and time, which makes the method more expensive. As it requires subsequent compaction by rolling, the concrete layer risks to be deformed in the lateral areas so that the edges need trimming. When paving in small widths, this may result in a waste of material up to 10%.

“VÖGELE is the Mercedes among the pavers”
Jürgen Weinhold, Managing Director of Altmarkbau, is happy knowing that prime pavement quality has been delivered and PCC has increased his profits. “We carried out the job without any major problems”, he said. “VÖGELE is the Mercedes among the pavers”. VÖGELE meanwhile easily manages to comply with specifications that were hard to be met in the past. The evidence: when paving PCC, the only pavers able to achieve the final density are those with the yellow canopies.

A close-textured surface along the sides and well shaped edges are evidence of a pavement’s high quality.