Mass Void Infill Case Study Leeds, Yorkshire
Regent Street Flyover Bridge
Propump placed 1,400m3 of light weight foam concrete in Leeds, Yorkshire to fill a void, this material had a wet density of 900kg/m3 and 28 day strength of 3N/mm2
this mass void fill involved tight site constraints as well as a strict density tolerance.
Regent Street Flyover
Regent Street Flyover Bridge, Leeds, Yorkshire
| Strength Requirement: | 2 N/mm2 – 3 N/mm2 |
| Density Requirement: | 900 kg/m3 (plastic wet Density) – 750 kg/m3 (Oven dried Density) |
| Volume Requirement | Entire project 1,400m³ |
Background:
Reinforced concrete structures contractor, CIDON GROUP were awarded the Concrete works package for the Regent Street Flyover Bridge refurbishment, in Leeds city centre. This involves building a new, enhanced structure to carry the A64(M). As part of these works, new supporting piers and abutment walls were poured in high quality concrete. Consequently, this involved replacing the section of bridge deck and constructing new obtaining walls to close off the old redundant spans.
A mass infill material that could be pumped and placed up-to 5 metres from ground level was required. as a result, of the works there were two redundant spans, each void equalled about 1,400 cubic metres.
The site at regent street, leeds was congested and there was very little room for plant and equipment as the city ring road was still running through the middle of site. Therefore, a requirement for a compact package that could produce and pump material was required.
Foam Concrete leeds flyover, Pre – construction site meetings to discuss the method and infill 
Foam Concrete leeds flyover, the first few deliveries of material being placed into the void 
Foam Concrete leeds flyover, the final pour of foam concrete to complete the void infill at leeds 
Material Specification
CIDON approached Propump engineering with the requirement for a 2 Newton aerated, foam concrete. However, they required an oven dried density of 750kg/m3. As a result, Propump Engineering leveraged their huge back catalogue of mixes and results to propose a foam concrete that would work for the application of filling the large void on regent street, Leeds.
The proposed foam concrete mix for Cidon in Leeds, Yorkshire, was a foam concrete “P950” with a target “plastic” density of 900kg/m3. Previous testing and oven drying trials had proven that this mix at this density as placed would oven dry to sub 750KG/m3. And produce a 28 day strength of at least 3 Newton. That’s right, foamed concrete with a 3 Newton strength and a dried density of 700kg/m3.
Foam Concrete Deliveries to site
Propump mobilised with their in-line foam concrete production system to be on-site for 2 weeks. Our operatives placed approximately 150 – 230 cubic meters per day to achieve an average 800mm daily lift.
Producing 200 cubic metres of foam concrete required only 15 deliveries of 6 cubic metres. Each delivery was processed into 13.6 cubic metres of foam concrete, using the in-line processing method. Therefore the overall number of on site deliveries were reduced, whilst simultaneously speeding up the rate of material production.
Our bespoke inline production method, and quality control, ensured that the 1400 cubic metre void was filled to within a 2% tolerance. Thats actual material placed versus theoretical volume.
This outstanding metric would have been impossible to achieve using any other production and placement method. CIDON had unfortunately already experienced this with another supplier during the phase 1 works.
Foam Concrete leeds flyover, pump line ready to start the mass infill 
Foam Concrete leeds flyover, the void is approaching the last fill marker Foam Concrete leeds flyover, the final pour of foam concrete to complete the void infill at leeds
Regent Street Flyover
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