The job site on the German A 48 motorway between Ochtendung and Mayen was a master stroke of productivity: a SUPER 2100-2 worked across a width up to 12.5m at a top pave speed of 4.5m/min. The machine laid some 4,200t of mix per ten-hour shift. This high laydown rate placed the drivers of the feed vehicles under great strain: roughly every three-and-a-half minutes, a feed lorry dumped its load into the MT 1000-1 Mobile Feeder’s storage hopper. However, everything went so smoothly that the job of paving a total of 51,000 tonnes of asphalt was wrapped up in just 18 days.

After about 40 years, the concrete pavement of the busy A 48 motorway was heavily damaged and needed reconstructing. The section concerned, running southbound to Trier, extended over 5,560m. The contract for pavement reconstruction was awarded to Heinz Schnorpfeil Bau GmbH. They began by removing the old pavement on the stretch passing through the Mayen-Koblenz district and then placed the new asphalt layers.

Daily laydown rate of 4,200 tonnes

The team from Schnorpfeil set themselves a breathtaking speed: “Our goal was to achieve a daily laydown rate of 4,200 t for the base course,” explained Thorsten Ragge, Senior Site Manager at Schnorpfeil. In order to meet this ambitious target, all parameters had to be co-ordinated perfectly. Two asphalt plants prepared the mix which was hauled to the job site by a fleet of 25 feed lorries. On average, a lorry transferred its load to the VÖGELE MT 1000-1 Mobile Feeder every three-and-a-half minutes, thus ensuring the SUPER 2100-2 was continuously replenished.

VÖGELE MT 1000-1 Mobile Feeder gets the job done

This was the first time that the Schnorpfeil team had used a material transfer vehicle. The MT 1000-1 Mobile Feeder from VÖGELE is an indispensable asset when it comes to ensuring smooth, uninterrupted paving. The shocks that may occur when the paver approaches a feed lorry are completely avoided, thus permitting the building of perfectly even asphalt pavements.

Paving in widths up to 12.5m

It was all down to the SUPER 2100-2 and the outstanding organization of contractor Schnorpfeil that this great feat was achieved. Equipped with a SB 250 Fixed-Width Screed in TP1 version, the heavy-duty machine operated across a width of 11.5m, with this even increasing to 12.5m in the areas of the motorway entrances and exits. The SB 250 Fixed-Width Screed is designed for large pave widths. Thanks to the screed frame’s high rigidity, absolutely even paving is always guaranteed. The unique VÖGELE pressure bar system which allows to achieve the highest possible degree of precompaction, can be used across the full pave width. This was amply demonstrated on the A 48 motorway, where base course was placed with a pressure bar operated at 80 bar. This resulted in a minimum need for subsequent compaction by rolling, which in turn had a positive effect upon pavement evenness.

Asphalt pavement designed for maximum loads

The asphalt layers for the motorway section under reconstruction were dimensioned in accordance with the German Directives for the Standardization of Traffic Area Surfaces (RStO) pursuant to Construction Class SV (for heavy traffic loads). For asphalt base, the mix type AC 32 TS (50/70) was used and placed in a thickness ranging from 9 to 28cm. For the 8.5cm asphalt binder course, mix of the type AC 16 BS (25/55-55A) was used and for wearing course stone mastic asphalt SMA 8 S (25/55-55A). The SUPER 2100-2 paved wearing course in a thickness of 3.5cm.

Outstanding evenness

Pavement evenness is crucial, primarily, for a road’s safety and ride comfort. With the reconstruction of the A 48 motorway section, the paving team achieved a genuine top-notch result in terms of evenness with the SUPER 2100-2 and SB 250 TP1 Fixed-Width Screed. At no point did the wearing course display a deviation from the specified value greater than ± 4mm -measured over a distance of 4m, thus fully complying with the specification.

A 48 fit for the future

“Thanks to the roadworks carried out, this stretch of the A 48 now fulfils the current Federal directives for busy motorways and is fit for the traffic loads of the coming decades,” explained Hendrik Hering, Minister of Transport for the State of Rhineland-Palatinate. “The reconstruction work has significantly improved both road safety and ride comfort on this motorway section”, he said.