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6872690 
Journal Article 
Metakaolin, a solution for the precast industry to limit the clinker content in concrete: Mechanical aspects 
Cassagnabere, F; Mouret, M; Escadeillas, G; Broilliard, P; Bertrand, A; , 
2010 
Yes 
Construction and Building Materials
ISSN: 0950-0618
EISSN: 1879-0526 
ELSEVIER SCI LTD 
OXFORD 
1109-1118 
WOS:000278039400003 
The current trend to decrease the clinker content in cements through the use of mineral additions in order to limit CO(2) emissions into the atmosphere is of major concern for the precast industry as the resulting binders are generally not very reactive at early ages. Here, composed cements (clinker + slag) or combinations between clinker and mineral admixtures are studied with a view to investigating the compressive strength of cement-based materials at both early (1 day) and later (28 days) ages under steam curing conditions. Limestone and siliceous fillers, silica fume and four metakaolins differing in their production process and impurity content were investigated. Considering performance, economic and environmental criteria, results in the laboratory showed that metakaolin (MK) is a very promising solution at a clinker replacement rate of 12.5-25% by mass. Compressive strength was significantly increased (1-day age) or practically the same as for reference mortars incorporating cement only (28-day age). Thus, in comparison with a reference concrete containing no MK and for an identical granular skeleton, the combination clinker/MK was validated in the precast factory in full-scale trials for slip-forming (25% replacement) and self-compacting (17.5% replacement) concrete applications: compressive strength and porosity were not affected. (C) 2010 Elsevier Ltd. All rights reserved.