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: Materials and Structures
Abreviated Serial title: Mater. Struct.
ISSN: 1359-5997
Publisher: RILEM Publications SARL
Volume: 35
Issue: 252
Issue date: 2002-10-01
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: 2002-08-17
Classification: Scientific Reports
Publication type : full_text
Public price (Euros): 0.00
doi: 10.1617/12682