CASE STUDY
BATCH-MIX SOLUTION (VIA MOBILE MIXING UNIT)FOR THE REINSTATEMENT OF A SEWER SCHEME
EXETER, 2009
CLIENT: SOUTH WEST WATER, BALFOUR BEATTY
Industry: Civils
For civils industries, we offer a permanent and temporary Soil Stabilisationsolution, for projects where large areas of ground material needs treatment,without having to remove material from site.
Application: In-situ
Our ex-situ application is for large, open projects where there is an on-goingrequirement for stabilisation, or sub-base material in large quantities and thereis space for the stockpiling of batch-mix material and machinery onsite.
EXECUTIVE SUMMARY
This case study presents the successful use of SMR Batch Mix via a Mobile Mixing Unit toaddress the challenges faced by Balfour Beatty Utility Solutions (BBUSL) in the sewer schemefor South West Water’s Cranbrook development near Exeter, which was conceived to be the firststand alone, self sufficient, low-carbon development in Devon since the Middle Ages. Byutilizing the SMR batch-mix and reusing wet arising material, the project achieved substantialreductions in costs, carbon footprint, and landfill usage.
PROBLEM STATEMENT
The sewer scheme produced 4000m3 ofextremely wet arising, consisting of sand andclay. These wet arisings created complications,as they couldn’t be transported off-site. Due tohigh moisture content, local landfills anddisposal sites would not accept the material,and the material itself would be extremelydifficult to transport as the moisture could seepor leak out during transport. Therefore, theoriginal plan to dispose of the excavatedmaterial at landfill and then importapproximately 8,500 tonnes of primary orrecycled aggregates for reinstatement was notpossible, yet alone cost effective norenvironmentally friendly.
THE SMR SOLUTION
To address the challenges, BBUSL instructed SMR UK to deploy Conroys’ Stabiltech MobileBatching Plant on-site. The wet material was combined with SMR binder through the mobilebatching unit at a half dose through a blending / mixing bucket, producing a recycledreinstatement material. This material was utilised as backfill, eliminating the need for disposalof spoil and imported aggregates.
RESULTS
Around 430 lorry journeys, associated with transporting off-site and importing aggregates,were eliminated. This significantly reduced the carbon footprint, road congestion, and projectcosts. All excavated arisings were repurposed into recycled capping material, leading to zerolandfill usage and zero primary aggregate consumption. The recycled stabilised cappingmaterial replaced imported primary aggregates for the backfill layer, reducing the demand forquarried aggregates.
BENEFITS
Environmental Impact Mitigation: By avoiding landfill and reducing aggregate imports, theproject significantly minimized its environmental impact.
Cost Savings: The elimination of transportation costs, landfill fees, and aggregate procurementresulted in substantial financial savings.
Efficient Resource Utilization: The mobile batching unit maximized the utilization of existing on-site materials. Streamlined
Project Timeline: On-site recycling reduced project duration, minimizing disruptions andexpediting completion.
CONCLUSION
The use of the Batch Mix solution via a Mobile Mixing Unit effectively resolved the challenges ofthe sewer scheme for South West Water’s Cranbrook development. By reusing wet arisings,reducing landfill and aggregate usage, and achieving significant cost and time savings, thiscase study demonstrates the practicality and benefits of innovative solutions such as the SMRbinder and on-site recycling techniques.
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