Pneumatic Delivery for Tunnel

LECA® LWA was specified for the disused Ratho Station in Edinburgh. This project required an urgent infill underneath the railway arch to maintain continued safety.

Selecting an aggregate infill was proving to be difficult for the construction team, with detrimental conditions including poor ground conditions and limited access to the railway arch. LECA® LWA was selected because of its lightweight properties, weighing 1/3 of traditional rock aggregate and also its ability to be pneumatically blown into place at a long distance through its piping system - resolving and solving these technical difficulties with ease.

Over 330m3 of LECA® LWA was pneumatically delivered through the blowing vehicle. This material was topped up with a local stockpile on site, making the delivery of material quick and efficient. Through this pneumatic delivery option, the speed of delivery ensured that the job was complete over a 2-day period, limiting the time required for a traffic controlled system above the railway arches.

LECA UK Sales Manager commented: “It was great to be a part of a project where LECA® LWA provided the problem-saving solution. Through discussing this with the engineers, it was quickly discovered that this project faced many uphill technical battles and this included poor ground conditions and limited access. Alternative aggregate media including traditional rock aggregate was proving to be too heavy and a logistical conundrum for the site engineers. It was recommended that LECA® LWA could provide a lightweight solution which could accomplish the geotechnical requirements to infill the railway arch, this included reduced settlement periods, increased stability and a significant reduction of horizontal earth pressure.”

“Furthermore, the unique option to pneumatically blow LECA® LWA through the LECA blowing machine with a pipe system which can be extended up to 50m ensured that the material could be delivered easily into the tunnel. Through stockpiling on site, this ensured that the required material could be delivered at an accelerated rate. The use of LECA® LWA also meant that traffic control was only required for two days and business as usual could be continued for the local community.”


Amount of material: 330m3 of LECA LWA (10-20mm)

Interesting Fact: This material was topped up with a local stockpile on site, making the delivery of material quick and efficient.

Delivery Method: Pneumatic Delivery

Main Contractor: 


Pneumatic Delivery


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