New advanced shotcrete admixtures: Internal curing
- MBT Holding, Zurich (Switzerland). Underground Construction Group
Tunnels and other underground construction projects have one of the worst curing conditions due to the ventilation that blows continuously dry (cold or hot) air into the tunnel. It can be compared with concrete exposed to a windy area. One would think that tunnels have ideal curing conditions with high humidity (water leakage), no wind and no sun exposure. However, this is not the case. MBT has developed a new system for more efficient and secure curing of wet shotcrete, repair mortars as well as concrete. Internal curing means that a special admixture is added to the concrete/mortar during batching as a normal admixture. This admixture produces an internal barrier in the shotcrete/concrete which secures safer hydration and better chemical resistance than the application of conventional curing agents. The benefits resulting from the new technology are impressive: The time consuming application and, in the case of various shotcrete layers, removal of curing agents are no longer necessary; curing is guaranteed from the very beginning of hydration; and there is no negative influence on bonding between layers. As a consequence of th is optimum curing effect, all other shotcrete characteristics are improved: density, final strengths, freeze/thaw and chemical resistances, watertightness, less cracking and shrinkage. In addition, MEYCO TCC 735 also improves pumpability and workability of shotcrete, even with low-grade aggregates. It particularly improves the pumpability of steel fiber reinforced shotcrete mixes. In combination with the MEYCO TCC system it contrives to even increase the beneficial effects of the slump killing system by further improving fiber orientation, reducing fiber rebound and thus raising toughness values.
- OSTI ID:
- 483906
- Report Number(s):
- CONF-9506349-; TRN: IM9726%%299
- Resource Relation:
- Conference: 7. conference on shotcrete for underground support, Telfs (Austria), 11-15 Jun 1995; Other Information: PBD: 1995; Related Information: Is Part Of Shotcrete for underground support 7: Proceedings; Klapperich, H. [ed.] [DMT, Essen (Germany)]; Poettler, R. [ed.] [Kling Consult, Krumbach (Germany)]; Willocq, J. [ed.] [Lafarge Fondu International, Paris (France)]; PB: 325 p.
- Country of Publication:
- United States
- Language:
- English
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