Posts Tagged ‘road layers’

Rain

January 20, 2011

Wet weather always makes work on a construction site far trickier, even simple operations like digging trenches for the electrical supply to the lighting columns become harder and take longer.

On the southern half of the scheme the ground is mostly clay – when it gets wet it tends to stick to the buckets of the excavators and if the excavated soil gets wet it doesn’t compact very well when it is placed back in the trench.

The rain since Christmas has made the clay in the verges very soft and sticky which then gets carried onto the road surface, and makes regular scrapping and cleaning of the surface necessary to minimise the build up of mud on the carriageway.

To minimise the risk of the finished surface being damaged, the final top layer of the road surfacing is left until as much of the work as possible is complete.

Before laying the top layer of surfacing, the road needs to be thoroughly cleaned to ensure that it bonds well to the lower layers. 

Once a section of the project is prepared for surfacing it has to be closed to site traffic to ensure it remains clean, this creates logistical problems in moving plant and materials around site.

Road widening

January 14, 2011

Littlemoor Road widening (large version)

On the north side of Littlemoor Road, opposite the Co-op, stone is being put in place as part of the road widening between Bincombe Bumps Roundabout and the start of the new Littlemoor Road. This will also enable the footpath on the supermarket side to be widened to form a shared cycleway / footway.

The stone is being levelled with a machine called a grader. It ensures that there are no hollows, which would have to be made up with bituminous material, or high points that would weaken the pavement design.

It is also easier to get a smooth surface on the final level if the top of the stone is uniform.

The widening work is steadily progressing eastwards towards Preston.

Last base layers

January 12, 2011

 Jurassic Roundabout (top) and Bincombe Bumps Roundabout (large version)

The Littlemoor roundabouts are now clearly visible.

Last week the base layers around Bincombe Bumps Roundabout were laid, and this week Jurassic Roundabout is having the base layers laid around it.

These are the last sections of base layer to be laid on the main carriageway.

November update

November 12, 2010

Littlemoor roundabouts Oct 2010 (large version)

During the rest of November surfacing works will continue across the scheme.

The surface course on the northern section – the main road from Dorchester end to Icen Lane – has been finished, and the white lining, road studs and barriers will be completed by the end of the month.

Kerbing and road construction will progress within the Littlemoor pond area with tarmac programmed to be laid at the end of November.

The Jurassic and Bincombe Bumps roundabouts are taking shape. There is still a significant amount of drainage work to be completed in the area, however, kerb and drainage kerb installation has started, which help mark out the form of the roads and roundabouts in the area.

The middle section of Littlemoor Road will be surfaced to binder course by the end of November, and work will then start on footpaths, street lighting and signage.

The Littlemoor corridor has been surfaced and work is progressing southwards completing the verge works.

At Two Mile Coppice the road formation is being completed. The main line around Veasta Roundabout and on to Manor Roundabout is programmed to be surfaced in the early part of December.

The science bit

November 9, 2010

Whatley Quarry (large version)

The asphalt (tarmac) for the Weymouth Relief Road is being produced at Hanson’s Whatley quarry near Frome in Somerset.

It is made up of three different materials, AC32HDMbase, AC20HDMbinder and Tuffgrip.

The AC32 and the AC20 are the lower layers, which are produced using limestone aggregate from Whatley quarry and the bitumen (tar) is supplied by Petroplus from their Coryton refinery in Essex.

Tuffgrip is one of Hanson’s branded products, it is a thin surfacing system that is produced using gritstone aggregate from Hanson’s Brayford quarry in North Devon, the bitumen is a polymer modified bitumen which is also supplied by Petroplus from their Coryton refinery.

The gritstone from Devon has better properties to improve skid resistance.

And if that makes no sense, at least you can appreciate the scale of the operation by looking at the aerial photo above.

Final surface

October 28, 2010

Work will begin next week to lay the final road surface on the road between Ridgeway to Icen Lane. Although this covers nearly two miles and three lanes, our contractors, Hanson are confident this work will take just over a week to complete, weather permitting.

(more…)

Weekend work

September 17, 2010

Littlemoor Gap tarmac (large version)

Lorton Lane chalk stabilisation (large version)Surfacing of the road has gone well so far. In the left photograph you can see the first strip of tarmac through the Littlemoor Gap.

This weekend there will be some work to ‘trim’ the rest of the surface to the correct level in preparation for more tarmac next week.

Hours of work will be from 8am to 5pm on both Saturday and Sunday.

Elsewhere in the south of the scheme, chalk stabilisation to create the foundation layer for the road is almost complete.

After the chalk is stabilised a thin layer is put on top of it to protect the surface, this is the black layer you can see in the right photograph taken south of the Lorton Lane bridge.

September focus

September 7, 2010

This month the focus in the south of the scheme is to complete chalk stabilisation (which forms the base of the road) and start surfacing.

Work will also continue on drainage for the links between the relief road, Manor Roundabout and Mercery Road. 

On Lodmoor, the drainage basin and most of the final top-soiling will be finished and the foundation layers of the new park and ride will continue to be laid. 

In the north section tarmac has now been placed from the Ridgeway to Icen Lane, and work is continuning to complete all the kerbs and road drainage. 

Surfacing of footpaths and bridleways in this area will be almost complete by the end of the month. 

For Littlemoor Road and the area by the Littlemoor roundabouts work will be focussed on completing the drainage.

Surfacing latest

July 28, 2010

Chapel Lane surfacing (large version)

The first layers of tarmac for the Relief Road have been laid from the Ridgeway south towards Icen Lane – here you can see the section underneath Chapel Lane bridge heading north.

Chapel Lane bridge is also currently being surfaced, and there are only a couple of weeks of work remaining to put in kerbing and drainage before this bridleway can be reopened.

July

July 2, 2010

Ridgeway balancing pond (large version)

June was a good month for the project, with fine weather meaning the bulk earth moving for the project has been finished.

During July the earthworks will be ‘trimmed’ to get the final levels for embankments and roundabouts correct. The main areas for this are Ridgeway, the balancing ponds at Littlemoor and the southern part of the scheme by Manor Railway bridge, Two Mile Coppice and Lodmoor. (more…)


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