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

  • Major Necaxa-Tihuatlan Highway project for Mexico
    October 1, 2014
    A new highway in Mexico is connecting Necaxa with Tihuatlan and the project features challenging terrain - Mauro Nogarin reports In Mexico a landmark highway project is now close to completion, having set a number of records for Latin America.
    Read More
  • Bitumen balance in RAP
    November 29, 2012
    *Bitumen from recycled asphalt can be rejuvenated using additives, according to Iterchimica The use of reclaimed asphalt pavement (RAP) is common in many countries. However, the aged bitumen from RAP has a lower penetration and is more viscous than when first mixed. This reclaimed bitumen is generally balanced by the addition of fresh binder that is softer than those typically used to produce hot mixes. But balancing penetration and softening point or viscosity will not deliver bitumen identical to the orig
    Read More
  • Plant advances for asphalt production boost efficiency
    May 30, 2018
    Advances in asphalt plant technology will boost efficiency for producers, while increasing the percentage of recycled materials that can be used in the mix - Mike Woof writes. Asphalt plant technology continues to advance as the rival firms fine-tune their technologies for greater performance. New plants can give higher quality output due to new control technologies, while also allowing for recycled asphalt pavement (RAP) to be used more efficiently, while still ensuring tight mix specifications are met. A
    Read More
  • Market development of low temperature asphalt in the UK
    November 20, 2014
    New developments in low temperature asphalt offer both cost and environmental benefits - Dr Nizar Ghazireh (Lafarge Tarmac) & Dennis Day (Nynas Bitumen) Low temperature asphalt (LTA) technology has considerable potential for reducing carbon emissions associated with road construction. The lower temperatures used to manufacture these materials mean that less energy is required and therefore lower emissions, which create better working conditions and result in lower impact on the environment.
    Read More

Highlighted Content