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)
Approach to Concrete Mix Design
Approach to Concrete Mix Design
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
Concrete Mix Design Spreadsheet
Concrete Mix Design Spreadsheet
Concrete Mix Design Spreadsheet
Concrete Mix Design Spreadsheet
Concrete Mix Design Spreadsheet
Concrete Mix Design Spreadsheet
Concrete Mix Design Spreadsheet
Concrete Mix Design Spreadsheet
Concrete Mix Design Spreadsheet
Experimental Regime
• Relationship between
compressive strength of
concrete and the freewater cement ratio. (BRE)
• Applicable to modern
binders?
Experimental Regime
• Relationship between
compressive strength of
concrete and the freewater cement ratio. (BRE)
• Applicable to modern
binders?
• Replicate for CEM II/A-L
and CEM III/A.
• Focus on shaded area.
Experimental Regime
CEM II/A-L
Mix No.
Binder
Content
(kg/m3)
A1
300
A2
350
A3
CEM III/A
Mix No.
Binder
Content
(kg/m3)
B1
300
B2
350
400
B3
400
A4
300
B4
300
A5
350
B5
350
A6
400
B6
400
A7
300
B7
300
A8
350
B8
350
A9
400
B9
400
Water-cement
Ratio
0.4
0.5
0.6
Watercement Ratio
0.4
0.5
0.6
Experimental Regime
• 18 Different Concrete Mixes
• Produced 180 Concrete Cubes
• Tested for:
• Slump
• Wet Density
• 7 & 28 Day Compressive Strength Tests
Compressive Strength Test Results
Comparison with the BRE
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
Water
Content
(kg/m3)
Wang & Ai
Expected
Slump
(mm)
Results of
CEM II/A-L
Tests
(mm)
Results of
CEM III/A
Tests
(mm)
120
-206.4
0
0
140
-111.7
20
20
150
-70.6
15
25
160
-33.1
30
40
175
16.7
30
55
180
31.8
140
Collapse
200
85.3
50
Collapse
210
108.2
Collapse
Collapse
240
164.7
Collapse
Collapse
Comments
Outside
Range of Wang
& Ai
Within
Range of Wang
& Ai
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?