Speed hardening system improves tunnel construction

BASF claims that its latest innovation will help improve efficiency in tunnel construction operations. Developed by BASF's Construction Chemicals division the new Crystal Speed Hardening system (CSH) is an advanced admixture technology aimed directly at the tunneling market.
February 14, 2012 Read time: 2 mins
The new concrete concept from BASF will help cut curing times
2645 BASF claims that its latest innovation will help improve efficiency in tunnel construction operations. Developed by BASF's Construction Chemicals division the new Crystal Speed Hardening system (CSH) is an advanced admixture technology aimed directly at the tunneling market. This product offers increases in efficiency for concrete casting, both for precast segments and cast in-situ linings. The fast-curing concept allows the removal of formwork at an earlier stage of the casting process and increases productivity. The product can shorten the length of time that formwork or shuttering has to be kept in position or by reducing the number of sets of formwork required. In addition to supporting efficiency, the system helps reduce CO2 emissions, optimises material use and meets high quality specifications according to the firm. It does so by providing high early strength development whilst balancing the requirement for an optimum mix through the use of more binding material and reduced clinker content.

The CSH concept uses a new hardening accelerator, X-SEED, to boost early strength development by modifying the action mechanism of cement hydration. X-SEED is made of suspended CSH-seeding crystals: the material added is of the same nature as the final hydration products from the cement reaction with water. As the suspended crystals are considerably smaller than microsilicas, the surface is much more beneficial for accelerating the crystal growth during the early stages of concrete hardening. The product has already been tried and tested in a number of tunneling trials. The abbreviation CSH also refers to calcium silicate hydrates; the cement hydration products responsible for the compressive strength of concrete. Hydration speed depends on the chemical composition of clinker and other cementitious materials. To simplify the science, by using BASF's X-SEED admixtures, a liquid suspension of synthetic crystal seeds on the nano scale, the growth of calcium silicate hydrate crystals is significantly accelerated.

Road Structures

For more information on companies in this article

Related Content

  • Brisbane's highway of distinction
    August 2, 2012
    A massive AU$2 billion update of the Gateway Motorway in Queensland is underway to improve an infrastructure stretched by population boom. Report and photographs by Adrian Greeman Just 20 years after the Australian city of Brisbane built its Gateway Motorway with a high slim signature bridge dominating the river skyline, the road is being completely revamped. Some 12km of urban route on the south of the Brisbane River is being expanded to take much increased traffic levels; the north is getting a completely
    Read More
  • New Midtown Tunnel open in Virginia
    January 30, 2017
    A project to construct the second Midtown Tunnel link in the US state of Virginia alongside the original connection has taken an important step forward – Mike Woof writes Commuters in the US state of Virginia will be pleased that the new Midtown Tunnel is now open to traffic, as it will help to boost capacity and cut congestion on the busy US 58 route connecting Norfolk and Portsmouth. The 1.13km tunnel link has been built to link with the interchange at Brambleton Avenue and Hampton Boulevard in Norfolk
    Read More
  • Beijing construction exhibition will break records
    February 16, 2012
    BICES organisers say a growth in the number of exhibitors, space and scope of the 2011 event assure it of success As the new US$33 billion Beijing-Shanghai 300km/hour bullet train swings into action the organisers of BICES 2011 are also claiming a world-class success. They say that the 11th Beijing International Construction Machinery Exhibition & Seminar 2011 has achieved what it planned with a 25% growth from the previous event (2009) in the number of exhibitors and floor space.
    Read More
  • Innovative solutions to earthmoving needs
    January 3, 2013
    Several manufacturers are offering improved earthmoving machines, with more to come - Mike Woof reports. One of the most notable developments comes from Caterpillar, with the unveiling of a hybrid excavator in the shape of its 336E H model. The machine is having its public launch at the bauma exhibition in Spring 2013 and will start rolling out of the factory in March 2013, while customers will be able to place orders from February 2013. Unlike other hybrid excavators on the market at present, the Cat 336E
    Read More

Highlighted Content