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U nited A rab Emirates U niversity F aculty of E ngineering. Design Concrete Mixture Incorporating SCM Graduation Project (II) Advisor :- Dr. Amr. El- Dieb Coordinator : - Dr. Tamer El Maaddawy Fahd Saeed Shehhi 200512722 Talal Ahmed Shehhi 200510258
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United Arab Emirates University • Faculty of Engineering • Design Concrete Mixture Incorporating SCM Graduation Project (II) Advisor :- Dr. Amr. El-Dieb Coordinator : - Dr. Tamer El Maaddawy Fahd SaeedShehhi 200512722 Talal Ahmed Shehhi 200510258 Khalid Al Hammadi 200507181 Saeed Al Ajmi 200440229 2010 Spring
Introduction (1/2) • Huge trend in the construction all over the world has proved the necessity of additives materials (SCM). • New challenges created by innovative engineers with spectacular designs of the structures ( BurjKhalifa ).
Introduction (2/2) • SCM must be used to enhance the quality of the concrete. • Raise new concerns regarding their impact on the economy and environment.
Purpose for this project • To establish a better understanding for fully utilizing of these materials in concrete production. • Optimizing the percentage of replacement of ordinary Portland cement with the suitable SCM to achieve the required properties.
Objectives • To apply concrete mixture design to concrete mixes with variable qualities. • Incorporating supplementary cementing materials (SCM) to further investigate their utilization in advanced application. • To be able to handle real life implementation and application of concrete incorporating SCM.
Supplementary Cement Material (SCM) • Materials that when used in conjunction with Portland cement contributes to the properties of hardened and fresh concrete through hydraulic or pozzolanic activity. • Typical examples are: • Fly Ash. • GGBS. • Silica Fume. • Metakaolin.
Proposed Conceptual Designs • Plan for casting 18 different mixes. • 108 cubes (10x10x10cm) are required for compressive strength test at 7, 28. • Also, we have planned to cast 18 cubes (15x15x15cm) for the resistivity test. • 36 cylinders (10x20cm) for RCPT.
Selected Conceptual Design (1/3) • We have reduced the mixes to be only 12 mixes. • For instance, regarding the Fly Ash we are only concerned about High Volume Fly Ash (HVFA). • The practical amount for GGBS was between 30% and 75%, and we have decided to go up to 90% to examine its effects.
Final Deliverables • In GP I, we have studied the properties of SCM. • In GP II, we have conducted experiments to asses the mixtures in order to: • Emphasize on the significant role of reducing the amount of cement by using SCM. • Achieving green environment.
Resistivity (1/3) Ability of the concrete to resist the flow of current especially the corrosion current associated with reinforcement corrosion.
Resistivity (2/3) Copper plate Ohm meter Sponge
How to Calculate Resistivity (3/3) • Diameter = 10 cm • Thickness = 5 cm
RCPT Test Stands for Rapid Chloride Permeability Test. This name is inaccurate as it is not the permeability that is being measured but ionic movement Electrical Indication of Concrete’s Ability to Resist Chloride Ion Penetration. Assessing concrete quality
Preparation Before RCPT Test 1 cm Epoxy 1 cm Cutting the specimens with the specified dimension. Sealing the concrete specimens with a layer of epoxy. Vacuuming for 24 hours.
RCPT Test Concept (1/2) Concrete specimen is subjected to a 60 V DC for 6 hours. In one reservoir is a 3.0 % NaCl solution and in the other reservoir is a 0.3 M NaOH solution. The total charge passed is determined and this is used to rate the concrete.
Charge Passed RCPT rating [6] Five levels are identified to classify the charge passed as corresponding to chloride ion penetrability of ‘‘high, moderate, low, very low, or negligible’’.
Tests Used • Slump to asses fresh concrete workability. • Compressive Strength Test (at 7, 28 Days). • RCPT Test (at 56 Days). • Resistivity Test (at 28, 56 Days).
RCPT (1/3) High Slope Low Slope
RCPT (2/3) • Control Mix: • Charge passed were less that 3909 Coulombs • Chloride Ion penetrability is moderate
RCPT (3/3) • Other mixes • Charge passed were less that 1000 Coulombs • Chloride Ion penetrability is very low. • Combination Mix [ GGBS 60% + SF 10%] • Charge passed = 50 Coulombs !!!! • Chloride Ion penetrability is Negligible.
Discussion of detailed design alternatives (1/2) • Concrete mix could be designed based on the requirements of the project. • These requirements could be strength, durability, workability, the cost any combination.
Discussion of detailed design alternatives (2/2) • The design alternatives could be one of the following: • Workable concrete mix • Concrete mix with high durability and strength (Early or late strength) • Concrete mix with low cost
Matrix Decision (1/2) • If you have several conceptual ideas, then the decision matrix helps you to select the best one, based on multiple evaluation criteria. • The conceptual ideas are rated against criteria the designer decides as relevant to the task.
Matrix Decision (2/2) The designer decides on importance ratings for each design criteria. Durability = 35 % Late Strength = 30 % Early Strength = 5 % Workability = 10 % Appearance = 5% Cost = 15 %
Formal Decision-Making Process on Selection of Final Details (1/3) Conceptual Design Ideas Design Criteria Weighting Factor
Durability = 20 % Late Strength = 15% Early Strength = 5 % Workability = 40% Appearance = 5% Cost = 15 %
Formal Decision-Making Process on Selection of Final Details (2/3)
Durability = 20 % Late Strength = 15% Early Strength = 5 % Workability = 10% Appearance = 5% Cost = 45 %
Formal Decision-Making Process on Selection of Final Details (3/3)
Analysis and Optimization (Relevant Standards & Codes) • Several tests were done to evaluate concrete quality • Some of these tests followed standards. • Compressive strength BS • RCPT ASTM C 1202 • Sorptivity ASTM C 1585.
Sustainability • SCM can reduce the embodied energy of precast concrete products by substituting waste materials for relatively high energy hydraulic cement • For each ton of supplementary cementing materials used in place of pure Portland cement, approximately one ton of greenhouse gas emissions is avoided . • Reduces air pollutant emissions • Reducing energy consumption