Description
Thames Tideway is a 25km, deep level super sewer in London. It follows the route of the Thames through London; Chelsea Embankment is one of the Thames Tideway project sites. Joseph Gallagher Ltd. were responsible for the delivery of the Sprayed Concrete (SCL) primary tunnel lining, utilizing a fiber reinforced sprayed concrete mix batched from dry silos on site.
Challenges
Contract requirements mandated the testing of the water-cement ratio of the spray concrete lining to ensure it met the strength and durability specification for the tunnel. The only solution available to the project team was to continuously run a gas-fired kiln and take water-cement ratio tests once per day. These tests were costly, unsafe, and didn’t provide the accuracy needed to make timely decisions about the quality of the concrete. Joseph Gallagher Ltd. And PERI worked with specialists from Vemaventuri to set up a trial of the SONO WC as an alternative to the current testing, and secured a contractual change to utilize the SONO in place of current measurement practices.
Solution and results
The SONO WC is a fully mobile, handheld device that provides a reading for the actual water content of the concrete within minutes. The team were able to carry out multiple measurements of each batch, replacing the kiln test which took 8 hours.
The probe provides a quick, repeatable measurement series for concrete sampling throughout the delivery of a pour. The information is available as the concrete is batched, ensuring that decisions regarding the quality of each concrete batch can be made before concrete is placed. The SONO WC provides a sampling methodology that is a significant improvement on other solutions; the trial demonstrated the accuracy of the probe and the equivalence to other testing methods with the improved speed and useability.
