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Optimization of ternary cementitious mortar blends using factorial experimental plans

Title: Optimization of ternary cementitious mortar blends using factorial experimental plans
Author(s): M. L. Nehdi, J. Sumner
Paper category : journal
Serial title: Concrete Science and Engineering
Abreviated Serial title: Concr. Sc. Eng.
ISSN: 1295-2826
Publisher: RILEM Publications SARL
Volume: 4
Issue: 15
Issue date: 2002-09-01
Publication year: 2002
Pages: 495 - 503
Total Pages: 9
Nb references: 13
Language: English

Abstract: Producing cements incorporating high-volume
replacement of ordinary portland cement (OPC) by recycled
industrial by-products is perceived as the most
promising venture for the cement and concrete industry
to meet its environmental obligations. However, the twocomponent
(binary) cements thus produced are often
associated with shortcomings such as the need for
extended moist-curing, increased use of chemical admixtures,
low early age strength, increased cracking tendency
due to drying shrinkage, and de-icing salt scaling problems.
There is need for research to investigate whether
high-volume replacement multi-component (ternary and
quaternary) cements could be optimized with synergistic
effects allowing component ingredients to compensate for
any mutual shortcomings. This study uses factorial experimental
plans to investigate the performance of OPC-silica
fume (SF)–class F fly ash (FA) and OPC-SF-ground granulated
blast furnace slag (GBFS) ternary cementitious
blends. Response surfaces for the superplasticizer requirement
to achieve a constant f low, setting time, drying
shrinkage up to 112 days, compressive strength at 1, 7, 28
and 56 days, and for the sulfate expansion up to 9-months
were obtained for up to 20%, 60%, and 60% replacement
levels of OPC by SF, FA and GBFS, respectively. A multiparametric
optimization is used to establish response surfaces
for a desirability function, which is used to rate
ternary cementitious blends. Results indicate that when
rheological, mechanical, durability and cost requirements
are combined; the use of costly mineral admixtures such
as silica fume is not economic in ternary OPC-SF-FA or
OPC-SF-GBFS blends beyond levels of about 3 to 5%.
Moreover, it is shown that the major hurdle for high-volume
replacement of OPC with class F fly ash is compromising
the early age performance. Results also indicate
that a good quality high-fineness GBFS can be used at
replacement levels of OPC up to 60% without major disadvantages.

Online publication: 2002-06-20
Classification: Scientific Reports
Publication type : full_text
Public price (Euros): 0.00

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