Project Reference: Shotcrete Slump Control
Location: Brisbane, Australia
Applicator/Contractor: Jemna/Transcity Joint Venture
Concrete Producer: Holcim
Market sector: Civil Tunneling
- MasterRoc HCA 20 a chemical admixture that controls the dynamics of cement hydration
- MasterSure 1008 a new generation super slump retaining aid for extended slump retention
- MasterRoc SA 167 a high-performance alkali-free set accelerator
- MasterSure 1008 retained the slump over an extended period of time.
- MasterRoc HCA 20 provided hydration control, ensuring security that the shotcrete would not hydrate throughout the extended period.
- MasterRoc SA 167 shotcrete accelerator was added to the mix while spraying the tunnel lining. This ensured high shotcrete early strengths were achieved.
Project Facts at a Glance
- Transcity Joint Venture consisted of Acciona, Ghella and BMD.
- Brisbane’s Lord Mayor Graham Quirk opened Legacy Way in July 2015.
- Extended slump retention technology has been utilised in other tunnel projects, including the Tintenbar to Ewingsdale Pacific Highway upgrade in Northern New South Wales.
- A number of underground mine sites have also successfully utilised this technology.
Product Facts at a Glance
- The liquid admixture MasterRoc HCA 20 can be used for wet and dry shotcrete mixes, therefore stabilising setting and hardening
- MasterRoc HCA 20 also controls hydration of all cement minerals
- The alkali-free set accelerator MasterRoc SA 167 is used for rock support, slope stabilisation and wet ground conditions
- MasterRoc SA 167 has quick setting properties allowing rapid work progress and has continual early-age strength development
- MasterSure 1008 is a slump retaining aid with the ability to work over a range of water binder ratios
- It has high workability, low shrinkage and creep, as well as being very durable in hot climates
The Customer's Benefit
- Shotcrete was able to be delivered to site during daylight hours but held for application throughout the evening.
- Less traffic to site during the night minimised the impact of tunneling operations to the neighboring residential community.
- Concrete supplier, Holcim, was able to minimise costly nightshift operations.
- The ability to control a constant working shotcrete slump minimised the need for re-tempering of the shotcrete mix, ensuring design compressive strengths would be maintained.
- Minimal traffic from concrete agitators allowed improved access to tunneling operations.