Article

La méthode du mortier de béton équivalent (MBE)—Un nouvel outil d’aide à la formulation des bétons adjuvantés

Materials and Structures (Impact Factor: 1.71). 04/2012; 33(8):475-482. DOI: 10.1007/BF02480524

ABSTRACT

This paper deals with a new method to design concrete containing admixture. Its principle is to design a mortar, deduced from the concrete composition and called concrete equivalent mortar (CEM), for which the rheological properties display correlation with those of concrete. The aim is to reduce the amount of concrete batches. This article presents the scientific approach which has led to this method, its field application and limits. The test procedure and the apparatus are detailed. An example of correlation between the rheological properties measured on CEM and on the corresponding concrete is presented. After monitoring fluidity versus time relationship, thermal measurements on CEM were carried out. These measurements allow to anticipate the effects of different admixtures on the setting time. One shows that the setting delays obtained on CEM are in good agreement with the difference of compressive strengths measured at early age. With rheological and thermal results, the CEM method permits to select between numerous admixtures, which is the most likely to fit in with the specifications of effectiveness (proportion/cost ratio), capacity of keeping the rheological properties over time and delay of formwork removal.

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    • "In this work, the second option was used. Schwartzentruber and Catherine [18] proposed the use of the concrete equivalent mortar (CEM) concept to study the rheology of fresh concrete with the assumption that the rheological properties of CEM should be correlated with those of the corresponding concrete. For CEM design it is considered that all friction phenomena take place at the cement paste/aggregate interface. "
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    ABSTRACT: This work studies the effect of incorporating fine recycled aggregates on the rheology of self-compacting concrete over time (at 15, 45 and 90 min). The fine fraction of the natural aggregates was replaced at 0%, 20%, 50% and 100% with recycled sand. The fresh-state properties were studied by empirical tests (slump-flow, J-Ring, L-Box) and fundamental ones in an ICAR rheometer. The mixes with 50% and 100% recycled sand lost their SCC characteristics at 90 min. Contrarily the mix with 20% replacement maintained suitable passing and filling ability. The causes of this trend were an initial increase of plastic viscosity and afterwards an increase of yield stress. The compressive strength of the 50% and 100% replacement mixes decreased significantly and that of the 20% replacement mix less than 10%.
    Full-text · Article · Oct 2015 · Construction and Building Materials
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    • "In this work, the second option was used. Schwartzentruber and Catherine [18] proposed the use of the concrete equivalent mortar (CEM) concept to study the rheology of fresh concrete with the assumption that the rheological properties of CEM should be correlated with those of the corresponding concrete. For CEM design it is considered that all friction phenomena take place at the cement paste/aggregate interface. "
    [Show abstract] [Hide abstract]
    ABSTRACT: This work studies the effect of incorporating fine recycled aggregates on the rheology of self-compacting concrete over time (at 15, 45 and 90 min). The fine fraction of the natural aggregates was replaced at 0%, 20%, 50% and 100% with recycled sand. The fresh-state properties were studied by empirical tests (slump-flow, J-Ring, L-Box) and fundamental ones in an ICAR rheometer. The mixes with 50% and 100% recycled sand lost their SCC characteristics at 90 min. Contrarily the mix with 20% replacement maintained suitable passing and filling ability. The causes of this trend were an initial increase of plastic viscosity and afterwards an increase of yield stress. The compressive strength of the 50% and 100% replacement mixes decreased significantly and that of the 20% replacement mix less than 10%.
    Full-text · Article · Aug 2015 · Construction and Building Materials
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