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DSE4 Final Year Project 2011/12. Concrete Mix D esign using Modern B inder M aterials. Brendan Cronin. Project Supervisor: Ted McKenna. The aim of this project is to develop mix design methods for modern day binder types. Objectives.
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DSE4 Final Year Project 2011/12 Concrete Mix Design using Modern Binder Materials Brendan Cronin Project Supervisor: Ted McKenna
The aim of this project is to develop mix design methods for modern day binder types
Objectives • Microsoft Excel based software solution for Concrete Mix Design • Comparison to the BRE design method for normal concrete mixes • Integrate the Wang and Ai formula • Compare and contrast the specification of a Total water content vs. a Free-water content
Modern Binders • Common concrete mix design guide • BRE Design of Normal Concrete Mixes • Based on Ordinary Portland Cement (CEM I) • Popular Modern Binders • More Sustainable • Better for the environment • CEM II/A-L – Portland-Limestone Cement • CEM III/A – Blastfurnace Cement (50% GGBS)
The Saturated Surface Dry Condition of Aggregates • Aggregates required to be in a SSD condition • Visual and physical inspection • IS EN 1907-6 Water Absorption of aggregates • IS EN 1907-5 Moisture Content of aggregates
Proportions of Aggregate Step 1: Grading • Particle size distribution tests – IS EN 933-1 (Sieve Analyses) • Grading limits – IS EN 12620
Proportions of Aggregate Step 1: Grading
Proportions of Aggregate Step 1: Grading
Proportions of Aggregate Step 1: Grading
Proportions of Aggregate Step 1: Grading
Proportions of Aggregate Step 1: Grading
Proportions of Aggregate • Combined grading curve • Compliance with industry standards
Proportions of Aggregate Roadstone Wood Limits
Proportions of Aggregate CEMEX Limits
Proportions of Aggregate Norman Palliser Limits
Proportions of Aggregate Norman Palliser Limits – Adjust curve to fit
Proportions of Aggregate Adjust curve to fit
Proportions of Aggregate Adjust curve to fit
Proportions of Aggregate Adjust curve to fit
Proportions of Aggregate Adjust curve to fit
Proportions of Aggregate Adjust curve to fit
Experimental Regime • Relationship between compressive strength of concrete and the free-water cement ratio. (BRE) • Applicable to modern binders?
Experimental Regime • Relationship between compressive strength of concrete and the free-water cement ratio. (BRE) • Applicable to modern binders? • Replicate for CEM II/A-L and CEM III/A. • Focus on shaded area.
Experimental Regime • 18 Different Concrete Mixes • Produced 180 Concrete Cubes • Tested for: • Slump • Wet Density • 7 & 28 Day Compressive Strength Tests
The Wang & Ai Formulae Sand-aggregate Proportion Where: C is the cement content per m3 of concrete ρC is the density of cement (kg/m3) W is the water content (10-3 kg)
The Wang & Ai Formulae Sand-aggregate Proportion
The Wang & Ai Formulae Water Content Equation Where: T is the slump (cm) W is the required water content (x 10-3 kg/m3)
The Wang & Ai Formulae Water Content Equation
Conclusions and Recommendations • The software solution simplifies the concrete mix design process and is accurate to within a margin of ± 4 MPa. • The Wang & Ai formula for aggregate proportions proves useful, however, the formula for water content proves inconclusive for the tested binders. • The results of the compressive strength tests show that the modern binders perform differently to the OPC, as used in the BRE, when plotted against the water/cement ratio. Recommend further suite of testing to substantiate this. • Including total water content with the specification of a concrete mix is not appropriate unless the aggregates and their proportions are constant.
Thank you for listening. Any Questions?